Crossover Fungal Pathogens: the Biology and Pathogenesis of Fungi

YFGBI 2598 No. of Pages 12, Model 5G 12 September 2013

Fungal Genetics and Biology xxx (2013) xxx–xxx 1 Contents lists available at ScienceDirect

Fungal Genetics and Biology

journal homepage: www.elsevier.com/locate/yfgbi

5 6

3 Crossover fungal pathogens: The biology and pathogenesis of fungi

4 capable of crossing kingdoms to infect plants and humans

⇑ 1 7 Q1 Gregory M. Gauthier , Nancy P. Keller

8 University of Wisconsin – Madison, Madison, WI, USA

9 10 article info abstract 2412 13 Article history: The outbreak of fungal meningitis associated with contaminated methylprednisolone acetate has thrust 25 14 Available online xxxx the importance of fungal infections into the public consciousness. The predominant pathogen isolated 26 from clinical specimens, Exserohilum rostratum (teleomorph: Setosphaeria rostrata), is a dematiaceous 27 15 Keywords: fungus that infects grasses and rarely humans. This outbreak highlights the potential for fungal patho- 28 16 Crossover fungi gens to infect both plants and humans. Most crossover or trans-kingdom pathogens are soil saprophytes 29 17 Q3 Trans-kingdom fungi and include fungi in Ascomycota and Mucormycotina phyla. To establish infection, crossover fungi must 30 18 Plant pathogenic fungi overcome disparate, host-speciﬁc barriers, including protective surfaces (e.g. cuticle, skin), elevated tem- 31 19 Human pathogenic fungi perature, and immune defenses. This review illuminates the underlying mechanisms used by crossover 32 20 Pathogenesis 21 Iron fungi to cause infection in plants and mammals, and highlights critical events that lead to human infec- 33 22 Velvet protein complex tion by these pathogens. Several genes including veA, laeA, and hapX are important in regulating biolog- 34 23 ical processes in fungi important for both invasive plant and animal infections. 35 Ó 2013 Published by Elsevier Inc. 36

37 38 39 1. Introduction highlights the ability for a subset of fungal pathogens to cause 56 infection in members of plant and animal kingdoms. 57 40 The outbreak of meningitis associated with contaminated Human fungal infections range from superficial nail and skin 58 41 methylprednisolone acetate from the New England Compounding infections (1.7 billion infections/year worldwide) to mucocutane- 59 42 Center has thrust the importance of invasive fungal infections into ous candidiasis (>85 million infections/year worldwide) to invasive 60 43 the public consciousness (reader is referred to companion piece by fungal infections (>2 million infections/year worldwide) (Brown 61 44 Andes and Casadevall, also Kainer et al., 2012; Smith et al., 2012). et al., 2012). Invasive fungal infections (IFI) in humans typically af- 62 45 Exserohilum rostratum (teleomorph: Setosphaeria rostrata), which fect persons with impaired immunity such as those undergoing so- 63 46 belongs to a group of dematiaceous (highly melanized) fungi that lid organ or hematopoietic stem cell transplantation. In this 64 47 cause necrosis of grasses (leaf spot, crown and root rot; reader is population, the incidence of IFIs is increasing (Pappas et al., 65 48 referred to companion piece by Turgeon), is the predominant 2010; Kontoyiannis et al., 2010; Bitar et al., 2009). The establish- 66 49 organism isolated from patient samples (Smith et al., 2012; Pratt, ment of the transplant-associated infection surveillance network 67 50 2005, 2003). Moreover, other potential phytopathogens (e.g., Clad- (TRANSNET), which tracks IFIs in the United States, has enabled a 68 51 osporium cladosporioides, Rhizopus stolonifer) have been identified deeper understanding of the epidemiology of fungal pathogens. 69 52 in contaminated methylprednisolone lots (Smith et al., 2012; In solid organ transplant recipients (SOT), Candida spp. (53%) and 70 53 Holmes, 2002; CDC). Before this outbreak, human E. rostratum Aspergillus fumigatus (19%) are the most common agents of IFI; 71 54 infections were rarely reported in the medical literature and lim- whereas dematiaceous fungi, Fusarium spp., mucormycetes, and 72 55 ited to persons with impaired immunity. Moreover, this outbreak other molds collectively represent 10% of IFIs (Pappas et al., 73 2010). In hematopoietic stem cell transplant (HSCT) recipients 74 Aspergillus fumigatus (44%) and invasive Candida spp. (28%) are 75 the most common pathogens (Kontoyiannis et al., 2010). IFI from 76 ⇑ Corresponding author. Address: Department of Medicine, Section of Infectious mucormycetes (8%), dematiaceous fungi (7%), Fusarium spp. (3%), 77 Q2 Diseases, School of Medicine and Public Health, University of Wisconsin – Madison, 78 1550 Linden Drive, Microbial Sciences Building, Room 3472, Madison, WI 53706, and unspecified molds (6%) occur at a higher frequency in HSCT USA. Fax: +1 (608) 263 4464. recipients than SOT recipients. Although non-Candida, non-Asper- 79 E-mail addresses: [email protected] (G.M. Gauthier), [email protected] gillus fungi represent a small proportion of IFIs, mortality associ- 80 (N.P. Keller). ated with these pathogens is substantial—39% mortality for SOT 81 1 Current address: Department of Medicine and Public Health, Department of recipients and 72–95.7% mortality for HSCT recipients (Pappas 82 Medical Microbiology, University of Wisconsin – Madison, 1550 Linden Drive, 83 Microbial Sciences Building, Room 3476, Madison, WI 53706, USA. et al., 2010; Kontoyiannis et al., 2010).

1087-1845/$ - see front matter Ó 2013 Published by Elsevier Inc. http://dx.doi.org/10.1016/j.fgb.2013.08.016

Please cite this article in press as: Gauthier, G.M., Keller, N.P. Crossover fungal pathogens: The biology and pathogenesis of fungi capable of crossing kingdoms to infect plants and humans. Fungal Genet. Biol. (2013), http://dx.doi.org/10.1016/j.fgb.2013.08.016 YFGBI 2598 No. of Pages 12, Model 5G 12 September 2013

2 G.M. Gauthier, N.P. Keller / Fungal Genetics and Biology xxx (2013) xxx–xxx

84 Epidemiologic data for agriculture fungal pathogens on a na- Ungerminated conidia of plant pathogenic fungi attach to the 146 85 tional scale is hindered by the complexity of monitoring diverse cuticle, which forms a hydrophobic surface composed of hydroxyl 147

86 types of food crops and limited resources for diagnostic testing. and epoxy fatty acids (C16,C18), waxes (epicuticular, intracuticu- 148 87 Thus, knowledge is primarily limited to large outbreaks of disease lar), phenolic compounds (e.g., cinnamic acids, flavonoids, lignins), 149 88 and global monitoring of wheat rust pathogens. Outbreaks of agri- and polysaccharides (Dominguez et al., 2011). The cuticle covers 150 89 cultural fungal pathogens are multifactorial in etiology and can in- stems, leaves, fruits, flowers, and seeds to protect the plant against 151 90 volve introduction of a novel pathogen, increased host susceptibility biotic and abiotic stresses (Dominguez et al., 2011). Conidial adhe- Q4 152 91 from reduced genetic diversity, and changes in climate (Vurro et al., sion prevents displacement by water or wind currents, and is asso- 153 92 2010). Cochliobolus species have been responsible for widespread ciated with germination and invasion (Mercure et al., 1994a,b). 154 93 destruction of important agriculture crops such as corn, which has Colletotrichum graminicola conidia adhere to plant tissues using a 155 94 resulted in famine and economic instability (Rossman, 2009). Global multi-stage process that involves (i) attachment of ungerminated 156 95 monitoring of the pathogens responsible for stem (Puccinia gramin- conidia to hydrophobic surfaces within 30 min of contact; (ii) re- 157 96 is), leaf (Puccinia triticina, Puccinia tritici-duri), and yellow (Puccinia lease of a glycoprotein containing matrix at the site of conidial 158 97 striiformis) rust diseases of cereal crops using field surveys has facil- attachment; and (iii) strengthening of the initial attachment by re- 159 98 itated interventions to minimize economic losses, which can be lease of glycoproteins from the appressorium (Mercure et al., 160 99 substantial—U.S. $1.12 billion/year (Pardey et al., 2013; Park et al., 1994a,b; Mercure et al., 1995; Sugui et al., 1998). Mucilage associ- 161 100 2011). In the United States, the establishment of the National Plant ated with conidial production provides protection from dessication 162 101 Diagnostic Network by the Agricultural Bioterrorism Act of 2002 (in but does not promote attachment to plant surfaces (Mercure et al., 163 102 response to the 9/11 terrorist attacks), has facilitated identification 1994a,b). Similarly, Fusarium solani conidia release an extracellular 164 103 and tracking of emerging plant pathogens including Phakopsora matrix upon contact with plant surfaces (Kwon and Epstein, 1997). 165 104 pachyrhizi, the etiologic agent of soybean rust. Within this matrix is a 90 kDa glycoprotein (mannoprotein) that is 166 105 Of the 1.5–5.1 million fungal species, an estimated 270,000 spe- postulated to function as an adhesin (Kwon and Epstein, 1997). 167 106 cies are associated with plants and 325 are known to infect hu- Attachment by this glue-like mechanism is shared by other patho- 168 107 mans (Blackwell, 2011; Hawksworth and Rossman, 1997; Robert genic ascomycetes including Magnaporthe oryzae (etiologic agent 169 108 and Casadevall, 2009; Woolhouse and Gaunt, 2007). A small subset of rice blast disease) and Blumeria graminis (powdery mildew of 170 109 of plant pathogens such as E. rostratum can cross kingdoms and in- cereals and grasses), and aquatic saphrophytes such as Lemonniera 171 110 fect humans. These crossover pathogens include fungi from Asco- aquatica (Hamer et al., 1988; Nielsen et al., 2000; Au et al., 1996). 172 111 mycota and Mucoromycotina phyla (Table 1)(Krishnam et al., Genes that regulate or contribute to conidial adhesion are poorly 173 112 2009; Pearson et al., 2010; Dignani and Anaissie, 2004; Nucci and understood. However, recent identification of TRA1, which encodes 174 113 Anaissie, 2007; Revankar and Sutton, 2010; Ribes et al., 2000; a transcription factor in M. oryzae, is beginning to provide insight. 175 114 Gomes et al., 2011; USDA ARS, 2013; Horst, 2008). The majority Deletion of TRA1 results in reduced spore tip mucilage, impaired 176 115 of ascomycete crossover pathogens belong to a group of highly adhesion to plant leaves, and altered transcript abundance for 177 116 melanized fungi collectively referred to as dematiaceous fungi in 100 genes in ungerminated spores (Breth et al., 2013). Deletion 178 117 the medical literature (Table 1). The majority of the dematiaceous of two of these differentially expressed genes, TDG2 and TDG6, also 179 118 fungi that cross kingdoms are in the dothideomycetes class (Table reduces conidial adhesion (Breth et al., 2013). Collectively, these 180 119 1). Despite the importance of basidiomycete fungi, none crossover data suggest TRA1 is an important regulator for genes involved 181 120 to cause infection in both plants and humans; however, human with pre-penetrative pathogenesis. 182 121 Cryptococcus pathogens can infect plants under laboratory condi- To initiate human infection, conidia must be internalized by 183 122 tions (Warpeha et al., 2013). The majority of crossover fungi are inhalation or directly penetrate the epidermis (Table 2). Structural 184 123 soil saprophytes capable of causing disease in plants (e.g., hemibio- constraints of the upper and lower respiratory system effectively 185 124 trophs, necrotrophs) and humans. In general, crossover fungi are restrict the size of particles that enter the alveolar space (Mullins 186 125 weak human pathogens that cause infection in persons with im- and Seaton, 1978). Because the epidermis is resistant to fungal 187 126 paired immunity or those who have sustained penetrating trauma invasion, conidia or mycelial fragments must enter through breaks 188 127 including iatrogenic (accidental medical) inoculation (Sexton and in the skin from trauma or iatrogenic inoculation. Similarly, dam- 189 128 Howlett, 2006; Dickman and de Figueiredo, 2011). age to the epithelial layer of the cornea is often a prerequisite for 190 fungal keratitis. Once inside the body, fungal conidia can interact 191 and bind to epithelia or basement membrane components such 192 as laminin and type IV collagen (Ibrahim, 2011). Conidial adhesion 193 129 2. Acquisition of infection and conidial adherence is thought to be a critical step involved with infection because it al- 194 lows direct access of the infectious propagule to host tissue and 195 130 To establish infection, fungi must attach to a susceptible host, minimizes physical removal by ciliated epithelia (Peñalver et al., Q5 196 131 germinate, penetrate tissue, replicate, and evade host immune de- 1996; Hernández et al., 2010). The conidia of Fusarium solani, a fre- 197 132 fenses (Table 2). Both plants and humans have developed protec- quent cause of keratitis, can adhere to the basement membrane of 198 133 tive barriers against IFI. Plant defenses include the cuticle, cell the cornea following damage of the epithelial layer (Dong et al., 199 134 wall, basal immunity, and effector-triggered immunity. Human de- 2005). Rhizopus oryzae conidia, which cause mucormycosis, can di- 200 135 fenses include an intact epidermis, architecture of the respiratory rectly adhere to laminin and type IV collagen, but not glycosamino- 201 136 system, core body temperature of 37 °C, innate immune defenses, glycans or fibronectin, prior to germination (Bouchara et al., 1996). 202 137 and cell mediated (adaptive) immunity. Aspergillus flavus weakly binds to fibronectin (Wasylnka and 203 138 The ability of fungal spores to adhere to the host is important Moore, 2000). 204 139 for the pathogenesis of plant and human pathogenic fungi. Mech- For the vast majority of crossover fungi (Table 1), mechanisms 205 140 anisms for adhesion to plant surfaces and mammalian tissue are that promote conidial attachment in human tissue have not been 206 141 heterogenous and include binding via preformed adhesives (se- investigated. On the basis of studies on Aspergillus fumigatus, 207 142 creted mucilage or extracellular matrix), hydrophobic interactions, Penicillium marneffei, and Paracoccidioides brasiliensis, mechanisms 208 143 and specific protein–protein or protein–carbohydrate interactions that mediate conidial adhesion for crossover fungi are likely to be 209 144 (Tucker and Talbot, 2001; Ibrahim, 2011; Srinoulprasert et al., diverse. A. fumigatus conidia bind to basal lamina components 210 145 2009). including fibronectin, laminin, types I and IV collagen, and 211

G.M. Gauthier, N.P. Keller / Fungal Genetics and Biology xxx (2013) xxx–xxx 3

Table 1 Invasive infections in plants and humans caused by crossover fungal pathogens.*

Ascomycota Plant disease Human disease Aspergillus spp. A. ﬂavus Seedling blight Ocular (trauma); otitis externa (trauma); sinus, lung, and SSTI infections (Trauma, SOT, HSCT, PI, Malignancy) A. niger Rot, seedling blight Otitis externa (trauma), cutaneous (HSCT, ALL, AML, AA), lung (PI, pre-existing cavity) Fusarium spp. F. oxysporum Wilt disease, stem canker, rot Ocular (trauma); sinus, lung, SSTI, and disseminated infections (Trauma, SOT, HSCT, PI, (root, bulb, stem) Malignancy) F. solani Wilt disease, rot (root, stem, Ocular (trauma); sinus, lung, SSTI, and disseminated infections (Trauma, SOT, HSCT, PI, crown) Malignancy)

Dematiaeceous Acrophialophora A. fusispora Secondary invader of plants Keratitis (trauma), brain abscess (ALL), lung infection (SOT) Aureobasidium A. pullulans Fruit russet Keratitis (post-operative), Lung (SOT), SSTI (HSCT, SOT), CAPD peritonitis, CRBI, disseminated (AML) Alternaria A. alternata Blight, leaf spot, fruit rot Post-traumatic keratitis, Cutaneous (SOT) A. dianthicola Blight, leaf spot, rot (stem, branch) SSTI (trauma) A. infectoria Black point on wheat SSTI (SOT) A. longipes Leaf spot SSTI (PI) A. tenuissima Blight, leaf spot SSTI (SOT, PI) Bipolaris B. australiensis Leaf spot, leaf blight Keratitis, brain abscess (AFS) B. hawaiiensis Leaf spot, seedling blight and wilt Keratitis (trauma), endopthalmitis, sinusitis, CNS infection B. spicifera Leaf spot, root rot Ocular, sinus, CNS (SOT), cutaneous (ALL), CAPD peritonitis Cladosporium C. Blight SSTI (PI, HIV, healthy), CNS (healthy), Lung cladosporioides C. oxysporum Leaf spot SSTI (trauma, Cushing syndrome) C. Secondary invader SSTI (healthy) sphaerospermum Colletotrichum C. coccodes Anthracnose, leaf spot, blight, root SSTI (NHL), disseminated (NHL) rot, wilt C. crassipes Fruit rot Cutaneous (SOT) C. dematium Anthracnose, blight, leaf spot Keratitis (trauma) C. Anthracnose, seedling blight, leaf SSTI (trauma, ALL, PI) gloeosporioides spot, rot C. graminicola Anthracnose, stalk rot, fruit rot Keratitis Coniothyrium C. fuckelii Graft canker, Cane blight Hepatic (AML) Corynespora C. cassiicola Leaf spot SSTI (DM) Curvularia C. geniculata Root rot, leaf mold, blight CAPD peritonitis C. inequalis cranberry rot, root rot, seed mold CAPD peritonitis C. lunata Blight, leaf spot Ocular, SSTI (SOT, ALL, PI), disseminated (SOT), CNS (healthy), prosthetic valve endocarditis, lung (healthy), breast implants (healthy) C. pallescens Leaf spot, rot Keratitis, CNS and lung (healthy), SSTI Dichotomophthoropsis D. Leaf spot Keratitis nymphaearum Exserohilum E. rostratum Leaf spot, blight, rot (root, crown) Keratitis (post-operative, trauma), sinusitis (AA, healthy), SSTI (trauma, lymphoma), disseminated (AA, ALL); meningitis, bone, joint, soft tissue due to contaminated methylprednisolone Lasiodiplodia L. theobromae Blight, canker, dieback, gummosis, Ocular (trauma) SSTI (trauma), sinusitis (healthy); pneumonia (SOT) rot (collar, root, stem-end) Macrophomina M. phaseolina Blight, damping-off, rot SSTI (HSCT, AML), disseminated infection (SOT) Microascus spp. M. cinereus Branch dieback Brain abscess (HSCT), SSTI (CGD), prosthetic valve endocarditis. M. cirrosus Leaf spot, seed rot Disseminated infection (HSCT) Mycoleptodiscus M. indicus Leaf spot SSTI (PI, SOT); myositis (PI); septic arthritis (trauma) Neoscytalidium N. dimidiatum Blight, canker, gummosis, leaf Endophthalmitis (trauma), Disseminated infection (neutropenia, SOT); cerebritis (healthy) spot, rot Phaeoacremonium P. krajdenii Petri disease SSTI (healthy) spp. Phoma spp. P. eupyrena Needle cast and blight of fur trees SSTI P. minutella Leaf spot SSTI (PI) Ulocladium U. chartarum Fruit spoilage SSTI (SOT)

Basidiomycota None – –

Mucoromycotina Mucor M. circinelloides Rot SSTI (DM, AML), Sinus (DM) M. hiemalis Rot SSTI (DM) Rhizopus R. arrhizus Rot CNS, sinus, lung, SSTI, GI and disseminated infections (Trauma, DM, SOT, HSCT, PI,

(continued on next page)

4 G.M. Gauthier, N.P. Keller / Fungal Genetics and Biology xxx (2013) xxx–xxx

Table 1 (continued)

Ascomycota Plant disease Human disease (oryzae) Malignancy) R. microsporus Rot CNS, sinus, lung, SSTI, GI and disseminated infections (Trauma, DM, SOT, HSCT, PI, Malignancy) Rhizomucor R. pusillus Rot CNS, sinus, lung, SSTI, GI and disseminated infections (Trauma, DM, SOT, HSCT, PI, Malignancy)

* This table lists the most common crossover pathogens and their associated diseases; thus, this table may not be all-inclusive. Denotes fungi belonging to the dothideomycetes class of fungi. Underlying medical conditions are listed in parentheses. AA is aplastic anemia; ALL is acute lymphoblastic lymphoma; AML is acute myelogenous leukemia; CAPD is continuous ambulatory peritoneal dialysis; CGD is chronic granulomatous disease; CNS is central nervous system; CRBI is catheter-related bloodstream infection; DM is diabetes mellitus; Healthy indicates no known immunosuppression; HSCT is hematopoietic stem cell transplant; NHL is non- Hodgkin’s lymphoma; PI is pharmacologic immunosuppression (e.g. prednisone, methotrexate, etc.); SOT is solid organ transplant; SSTI is skin and soft tissue infection.

Table 2 Mechanisms for infection for crossover pathogens in plants and humans.

Mechanism Plants Humans

Acquisition of Infection Conidial adherence to plant stems, leaves, roots Inhalation of aerosolized conidia into lungs or sinuses Conidial entry into wounded tissue Traumatic penetration into the skin and soft tissues Conidial germination Factors inﬂuencing germination: Thermotolerance (37 °C) Plant surface hydrophobicity Suppression of host immune defenses Plant surface hardness Evasion of immune cells Water activity Conidial density Ambient temperature Plant derived compounds (e.g. ﬂavonoids) Invasion and destruction of tissue Penetration through intact tissue or openings Uptake of germinating conidia by pneumocytes Hyphal invasion Hyphal invasion of intact tissue Appressorium formation Iron acquisition and homeostasis Iron acquisition and homeostasis Velvet protein complex Velvet protein complex

212 fibrinogen (Peñalver et al., 1996; Gil et al., 1996; Tronchin et al., defenses (Linder et al., 2005; Aimanianda et al., 2009; Dagenais 246 213 1997; Yang et al., 2000; Upadhyay et al., 2009). Binding of fibronec- et al., 2010). Recent analysis of Hyd2, which encodes a hydrophobin 247 214 tin is mediated by 23 and 30-kDa polypeptides on the conidial cell found on the conidial cell surface of Beauveria bassiana, demon- 248 215 surface, whereas 23-kDa, 72-kDA, and CalA proteins facilitate bind- strated that Hyd2 is important for adherence of ungerminated con- 249 216 ing to laminin (Peñalver et al., 1996; Gil et al., 1996; Tronchin et al., idia to insect epicuticle (Zhang et al., 2011). B. bassiana is a plant 250 217 1997; Upadhyay et al., 2009). In addition, negatively charged carbo- endophyte capable of infecting several species of insects (Zhang 251 218 hydrates (e.g. sialic acids) on the conidial cell surface may also et al., 2011). Thus, it is tempting to speculate that hydrophobins 252 219 mediate attachment (Wasylnka and Moore, 2000; Wasylnka et al., may promote the ability of conidia to adapt to different environ- 253 220 2001). Moreover, affinity for extracellular matrix components is ments (plant surface, insect epicuticle, mammalian lung) to facili- 254 221 species specific. A. fumigatus conidia have a greater affinity for fibro- tate adhesion. In fact, there is interest in exploring the potential of 255 222 nectin than less common agents of invasive aspergillosis such as A. fungal hydrophobins as orthopedic implant coatings due to their 256 223 flavus and A. wentii, or non-pathogenic A. ornatus (Wasylnka and native adherent properties (Boeuf et al., 2012). 257 224 Moore, 2000). The conidia of P. brasiliensis, the etiologic agent of par- 225 acoccidioidomycosis, possess a 32-kDa protein, PbHAD32, on the 226 conidial surface that mediates binding to laminin, fibronectin, 3. Conidial germination: physicochemical stimuli, structural 258 227 fibrinogen, and pulmonary epithelial cells (Hernández et al., barriers, and temperature adaptation 259 228 2012). Silencing PbHAD32 by RNA interference resulted in attenu- 229 ated virulence in a murine model of infection (Hernández et al., The conidia of crossover fungi can germinate on seed, root, or 260 230 2010). The conidia of Penicillium marneffei, which causes penicillio- aerial plant surfaces and in lung, corneal, or cutaneous tissues. 261 231 sis in immunocompromised persons in Southeast Asia, are capable Conidia are capable of remaining in a dormant state until the prop- 262 232 of adhering to different pattern recognition receptors including er stimuli induce germination, which consists of isotropic spore 263 233 mannose receptors, toll-like receptors (TLR1, 2, 4, 6) and integrins swelling, development of cell polarity, germ tube formation, and 264 234 (CD11b, CD14, CD18) (Srinoulprasert et al., 2009). infection structure differentiation (e.g. appressorium, haustoria, 265 235 Despite the substantial differences between substrates encoun- or hyphae). Moreover, the conidia of plant pathogenic fungi can 266 236 tered by conidia from crossover fungi, the presence of hydropho- contain inhibitory molecules to inhibit germination until specific 267 237 bins on the conidial surface may represent a shared, although environmental and host conditions are met (Leite and Nicholson, 268 238 largely unexplored mechanism that may affect adherence. 1992). The diverse host-ranges for these crossover fungi reflect 269 239 Hydrophobins are amphipathic proteins characterized by 8 con- the ability of these pathogens to adapt to and sense a wide range 270 240 served cysteine residues and are located on the surface of conidia of stimuli to promote germination and subsequent infection. 271 241 and hyphae. The functions of these proteins are diverse and include Factors that induce conidial germination on plants include the 272 242 reduction of water surface tension to promote aerial growth of hy- surface architecture, water activity, ambient temperature, conidial 273 243 phae, dispersal of conidia in water droplets, enhancement of adhe- density, and plant-derived compounds such as flavonoids, waxes 274 244 sion for germinated conidia, formation of appressoria, protection of and root exudates (Bagga and Straney, 2000; Barhoom and Sharon, 275 245 conidia against phagocytosis, and evasion of innate immune 2004; Srivastava et al., 2005; Nanguy et al., 2010)(Table 2). Nutri- 276

G.M. Gauthier, N.P. Keller / Fungal Genetics and Biology xxx (2013) xxx–xxx 5

277 tional signals such as exogenous glucose are postulated to play a and soil saprophytic fungi demonstrated that for every 1 °C in- 343 278 minor role in germination of plant pathogenic fungi. Architectural crease in temperature above 30 °C, the number of fungi that could 344 279 features that induce germination include hydrophobicity and hard- grow progressively declined (Robert and Casadevall, 2009). The 345 280 ness of the plant surface (Chaky et al., 2001; Kim et al., 1998; Liu conidia of crossover pathogens such as A. niger, B. australiensis, 346 281 et al., 2007). The ability to sense surface hardness or thigmotro- B. hawaiiensis, C. clavata, C. pallescens, C. senegalensis, F. solani and 347 282 pism, is important for germination and formation of infection L. theobromae (Table 1) are capable of germination and hyphal 348 283 structures for many plant pathogens (Kim et al., 1998; Liu et al., growth at 37 °C in vitro; however, hyphal development and replica- 349 284 2007). The conidia of Colletotrichum species including C. graminico- tion is suboptimal when compared to lower temperatures (Alma- 350 285 la and C. gloeosporioides preferentially germinate on rigid rather guer et al., 2013; Yang, 1973; Araujo and Rodrigues, 2004; Mehl 351 286 than soft surfaces (Chaky et al., 2001; Kim et al., 1998). The combi- and Epstein, 2007; Saha et al., 2008). In contrast, A. flavus 352 287 nation of a hard, hydrophobic surface along with plant-derived germination frequency is enhanced at 37 °C compared to 30 °C, 353 288 compounds affects the number of germ tubes that emerge, forma- but germination kinetics are substantially slower than A. fumigatus, 354 289 tion of appressoria, and virulence (Barhoom and Sharon, 2004). which is the predominant pathogen for invasive aspergillosis (Ara- 355 290 Germination of C. gloeosporioides in soft media prior to plant inoc- ujo and Rodrigues, 2004). The ability for humans to maintain body 356 291 ulation results in decreased pathogenicity when compared to con- temperature higher than the surrounding environment creates a 357 292 idia directly inoculated onto the plant surface or pre-germinated in ‘‘thermal exclusionary zone’’ that can inhibit or impede germina- 358 293 pea extract (Barhoom and Sharon, 2004). Moreover, C. gloeosporio- tion and growth for the vast majority of fungi (Casadevall, 2012). 359 294 ides uses different germination strategies for saprophytic and path- However, temperature is not uniform throughout the body; 360 295 ogenic growth (Barhoom and Sharon, 2004). extremity and corneal tissues are lower than core body tempera- 361 296 The molecular mechanisms underpinning conidial germination ture of 37 °C(Kessel et al., 2010). This slight reduction in temper- 362 297 are slowly being elucidated. In C. gloeosporioides, calcium-calmodu- ature has the potential to allow for infection by fungi whose 363 298 lin signaling promotes germination and formation of appressoria germination and growth would otherwise be compromised at 364 299 following physicochemical stimulation (hard surface plus ethylene) 37 °C. 365 300 (Kim et al., 1998). Contact with hard surfaces induces transcription The concept that core body temperature can influence host sus- 366 301 of calmodulin and protein phosphorylation by calmodulin kinase ceptibility to fungal infection is not limited to humans and is rele- 367 302 (Kim et al., 1998). In addition, specific sets of genes that encode vant to other mammals, insects, and amphibians. Geomyces 368 303 Colletotrichum hard-surface induced proteins (CHIP1-8) are induced destructans (recently renamed as Pseudogymnoascus destructans 369 304 following contact with hard surfaces; however, they are not known (Minnis and Lindner, in press)), the etiologic agent of white nose 370 305 to impact conidial germination or formation of appressoria (Kim disease in insectivorous bats, is a psychrophile (cold loving) fungus 371 306 et al., 2002). Investigation of thigmotropism in the grass pathogen that infects the nose, muzzle, ears, and wings leading to hypotonic 372 307 Magnaporthe has demonstrated that RGS1, a GTPase accelerating dehydration, electrolyte disturbances, disordered acid–base bal- 373

308 protein that directly interacts and inhibits MagA (Gas), is involved ance, and premature fat depletion (Lorch et al., 2011; Warnecke 374 309 with the genetic program in response to germination on hard sur- et al., 2012, 2013). White-nose disease has killed >5 million bats 375 310 faces (Liu et al., 2007). in 19 U.S. states and 4 Canadian provinces since it was first discov- 376 311 In addition to their role in thigmotropism, G protein signaling ered in New York state in 2006 (Blehert, 2012). G. destructans rep- 377 312 affects conidial germination. Deletion of Fgb1, which encodes a lication is optimal at 12.5–15.8 °C with an upper limit of 19.0– 378 313 G protein b subunit in the plant vascular wilt fungus F. oxysporum, 19.8 °C in vitro (Verant et al., 2012). Bats are susceptible to 379 314 results in higher germination frequency and elevated intracellular white-nose syndrome only during hibernation, which is when they 380 315 cAMP levels (Jain et al., 2003). Conidia of F. solani germinate in re- drop their core body temperature to a level that is permissive for G. 381 316 sponse to various flavonoid compounds, which are lipophilic and destructans growth (Blehert, 2012). Several species of insects 382 317 can easily penetrate the conidial cell wall. The mechanism under- including the housefly (Musca deomestica), locusts (Locusta migra- 383 318 lying flavonoid-mediated germination involves inhibition of cAMP toria, Schistocerca gregaria), and grasshoppers (Oedaleus senegalen- 384 319 phosphodiesterase, which results in elevated conidial cAMP sis, Melanoplus sanguinipes) can induce fever by basking in warm 385 320 concentrations (Bagga and Straney, 2000). Moreover, higher germi- temperatures to combat invasive fungal infections (Anderson, 386 321 nation frequency is often associated with stronger inhibition of 2013; Ouedraogo et al., 2002). These behavioral fevers are postu- 387 322 cAMP phosphodiesterase (Bagga and Straney, 2000). In contrast lated to impair fungal growth by elevating core body temperature 388 323 to F. solani, deletion of CGB1, which encodes a G protein subunit and stimulating a robust immune response (Anderson, 2013). 389 324 in the corn blight pathogen Cochliobolus heterostrophus (anamorph: Houseflies infected with Beauveria bassiana or Entomophthora mus- 390 325 Bipolaris maydis) impairs conidial germination (Ganem et al., cae seek locations with high ambient temperature when compared 391 326 2004). In addition to cAMP-mediated pathways, other signaling to uninfected flies (Anderson et al., 2013; Watson et al., 1993). For 392 327 cascades such as RAS/MAPK cascades are involved with the germi- flies infected with B. bassiana, behavioral fever delays death and al- 393 328 nation of agricultural pathogens. Genome-wide gene expression lows females more time to lay eggs (Anderson et al., 2013). In 394 329 analysis of the cereal pathogen Fusarium graminearum has shown contrast, elevation in core body temperature facilitates cure and 395 330 that substantial alteration in gene transcription occurs at different increases survival following E. muscae infection (Watson et al., 396 331 stages of conidial germination (Seong et al., 2008). 1993). Behavioral fever in L. migratoria locusts infected with Meta- 397 332 To cause infection in humans, conidia must not only overcome rhizium anisopliae serves to maintain hemocyte concentration in 398 333 structural barriers that impede entry into the host (e.g. skin, lung the hemolymph, increase phagocytic activity, and inhibit fungal 399 334 architecture), but need to germinate under conditions of elevated growth (Ouedraogo et al., 2002, 2003). To combat the beneficial ef- 400 335 temperature, slightly alkaline pH of 7.4, and evade the immune fect of elevated temperature, Metarhizium robertsii produces a sec- 401 336 system (Table 2)(Casadevall, 2005; Robert and Casadevall, 2009). ondary metabolite, destruxin A, which interferes with behavioral 402 337 Core human body temperature (37 °C) is postulated to serve as a fever and leads to the death of S. gregaria locusts (Hunt and 403 338 major defense mechanism against IFI by restricting growth (Robert Charnley, 2011). 404 339 and Casadevall, 2009). Computational modeling predicts that Similar to behavioral fever, external application of heat can be 405 340 36.7 °C provides the greatest degree of protection against invasive used to treat certain fungal infections of amphibians and humans. 406 341 fungal infection with the least metabolic cost (Bergman and Casa- Batrachochytrium dendrobatidis, the etiologic agent of chytridiomy- 407 342 devall, 2010). Analysis of a large collection of animal, insect, plant, cosis, which is devastating amphibian populations worldwide, 408

6 G.M. Gauthier, N.P. Keller / Fungal Genetics and Biology xxx (2013) xxx–xxx

409 grows between 6 and 28 °C with optimal replication at 17–23 °C of plant damage depends on the invasive lifestyle of the fungus. 472 410 (Voyles et al., 2009; Woodhams et al., 2003). This pathogen infects Following penetration of the cuticle and plant cell wall, biotrophs 473 411 keratinized epithelial cells resulting in disordered electrolyte (Na+, such as mildews and rusts cause minimal damage and live inside 474 + À 412 K ,Cl ) balance and H2O absorption, which culminates an asystolic the plant cell (intercellular, intracellular, subcuticular) without 475 413 cardiac arrest (Voyles et al., 2009). In addition, diseased frogs dis- causing death (Mendgen and Hahn, 2002). In contrast, necrotophs 476 414 play elevated corticosterone concentrations, increased resting met- such as Alternaria and Fusarium spp. kill the host before an effective 477 415 abolic rate, suppressed appetite, reduced body mass, and altered immune response can be generated and feed on the dead plant 478 416 leukocyte counts (Peterson et al., 2013). Exposure of infected frogs material. Plant death is mediated by hyphal invasion, secretion of 479 417 to 37 °C for 16 h or 30 °C for 10 days results in 100% and 96.4% cure degradative enzymes, phytotoxins, and reactive oxygen species 480 418 rate, respectively (Woodhams et al., 2003; Chatfield and Richards- (Horbach et al., 2011). Some fungi such as Colletotrichum spp. have 481 419 Zawacki, 2011). In humans, the dimorphic fungal pathogen Sporo- a hemibiotrophic lifestyle in which they infect the host as a bio- 482 420 thrix schenckii causes cutaneous nodules and ulcers following trau- troph and then switch to necrotrophic growth to kill the plant 483 421 matic inoculation. Local hyperthermia (42–43 °C) can be used as (Münch et al., 2008). 484 422 adjunctive therapy for patients with fixed cutaneous sporotrichosis Mechanisms for invasion of crossover fungi are diverse and in- 485 423 (Kauffman et al., 2007). The elevation in temperature is postulated clude entry through natural openings (e.g. stomata), wounds, or 486 424 to inhibit growth of S. schenckii and enhance killing by neutrophils penetration through intact plant tissue by hyphae or appressoria 487 425 (Hiruma and Kagawa, 1986). The utility of local hyperthermia for (Table 2). The hyphae of F. oxysporum surround and invade the pri- 488 426 other human fungal pathogens remains limited; however, it has mary and lateral roots without forming specialized structures. 489 427 been successfully used to treat cutaneous Alternaria alternata infec- Invasion results in plant cell collapse from loss of turgor pressure, 490 428 tion and chromoblastomycosis (Torres-Rodriguez et al., 2005; cessation of root growth and eventual collapse of root structure 491 429 Hiruma et al., 1993). (Czymmek et al., 2007). Following entry into the root, F. oxysporum 492 430 The molecular mechanisms underlying thermotolerance are invades vascular tissue, grows rapidly (>2.8 lm/min), and chokes 493 431 complex and poorly understood. Research on temperature adapta- off nutrient and water transport leading to wilt and plant death 494 432 tion has primarily focused on the most common agents of invasive (Czymmek et al., 2007). In addition, the phytotoxin fusaric acid 495 433 mycosis. Gene expression analysis of A. fumigatus following an in- contributes to water loss and high concentrations can be detected 496 434 crease in temperature from 30 °Cto37°C identified 726 differen- in leaves, which are not invaded by F. oxysporum (Dong et al., 497 435 tially expressed genes with many involved with translation, 2012). The molecular mechanisms underlying Fusarium invasion 498 436 amino acid, carbohydrate, lipid, and energy metabolism (Do and virulence involve activation of Fmk1 MAPK, cAMP-PKA and 499 437 et al., 2009). Temperature elevation also induced increased gene G-protein signaling pathways, proper regulation of nitrogen 500 438 expression of heat shock proteins which was associated with a metabolism by Fnr1, assimilation of alternative carbon sources by 501 439 transient decrease in transcripts involved with carbohydrate and Frp1 and Snf1, peroxisomal biogenesis, Zn(II)2Cys6 transcription 502 440 energy metabolism during the early stages (<60 min) of germina- factors (Fow2, Ftf1), and detoxification of plant derived compounds 503 441 tion (Do et al., 2009). Similarly, Lamarre and colleagues identified by Tom1-mediated hydrolysis or the b-ketoadipate pathway 504 442 787 differentially expressed genes during the first 30 min of A. (Michielse and Rep, 2009; Divon et al., 2006; Imazaki et al., 505 443 fumigatus conidial germination at 37 °C(Lamarre et al., 2008). 2007; Jonkers et al., 2009; Ospina-Giraldo et al., 2003; Pareja-Jaime 506 444 These genes were predicted to be involved with respiration, transet al., 2008; Michielse et al., 2012). Similar to F. oxysporum, G-pro- 507 445 lation, RNA biogenesis, and amino acid, protein, carbohydrate and tein Cbg1 and MAPK kinase Chk1 in C. heterostrophus (anamorph: 508 446 lipid metabolism (Lamarre et al., 2008). Moreover, in ungermi- B. maydis) are important for invasion of corn leaves (Ganem 509 447 nated conidia, pre-processed mRNA transcripts were detected for et al., 2004; Lev et al., 1999). MAPK, cAMP-PKA and G-protein sig- 510 448 27% of the total genome (Lamarre et al., 2008). The presence of naling pathways, in particular, are universally conserved signaling 511 449 pre-processed transcripts has also been detected in ungerminated pathways important in pathogenesis of both plants and humans 512 450 conidia of A. niger (25% of genes) and F. graminearum (42%) (van (reviewed in Kozubowski et al., 2009; Li et al., 2012). 513 451 Leeuwen et al., 2013; Seong et al., 2008). The large percentage of Another conserved molecular pathway regulating virulence in 514 452 pre-formed transcripts is postulated to facilitate rapid growth both plant and human pathogenic fungi is the Velvet complex, first 515 453 and adaptation to the external environment once the genetic pro- described in the saprophyte A. nidulans (Bayram et al., 2008). The 516 454 gram inducing germination is initiated (van Leeuwen et al., 2013). Velvet and associated complexes (composed of LaeA, VeA, VelB 517 455 The ability to adapt to elevated temperature is necessary but and VelC) in F. oxysporum regulate fungal development, chromatin 518 456 not sufficient for crossover fungi to establish infection. These remodeling, secondary metabolite production, and contribute to 519 457 pathogens must also overcome innate and adaptive immune host pathogenesis. Deletion of veA, velB and laeA, but not velC results 520 458 defenses. In contrast to primary human fungal pathogens such as in attenuated virulence in both plant and mammalian hosts and 521 459 Blastomyces dermatitidis, Histoplasma capsulatum, Coccidioides spp. decreases production of the mycotoxin beauvericin (López-Berges 522 460 and Paracoccidioides brasiliensis, crossover fungi are often unable et al., 2013). Deletion of these genes in other fungi have also been 523 461 to survive attack by host immune cells. Thus, impairment of the in- associated with decreased production of degradative enzymes, 524 462 nate (neutrophils, macrophages, NK cells) and adaptive (Th1 and which also contribute to successful invasion processes in patho- 525 463 Th17 T lymphocytes) immune systems is required for the vast a genic fungi (Amaike and Keller, 2009; Karimi-Aghcheh et al., 526 464 majority of fungi to establish invasive infection (LeibundGut- 2013). Several cell wall degrading enzymes such as pectate lyases, 527 465 Landmann et al., 2012). Immune host defenses for most patients polygalacturonases, xylanases, and proteases are released during 528 466 with crossover fungal infections are impaired by hematologic root penetration; however, the contribution of these enzymes to- 529 467 malignancy, pharmacologic immunosuppression, and transplanta- wards pathogenesis has been difficult to elucidate due to func- 530 468 tion (Table 1). tional redundancy (Jonkers et al., 2009; Michielse and Rep, 2009). 531 Biotrophic, hemibiotrophic, and some necrotrophic fungi use a 532 specialized invasion structure called an appressorium to penetrate 533 469 4. Tissue invasion and manifestations of disease intact plant tissue. The molecular biology underlying appressorium 534 formation has been an area of intensive investigation with detailed 535 470 Following conidial germination, plant pathogenic fungi launch a molecular knowledge obtained from Magnaporthe oryzae, which is a 536 471 multifaceted attack to invade and feed on host tissues. The degree strict phytopathogen (Wilson and Talbot, 2009; Caracuel-Rios and 537

G.M. Gauthier, N.P. Keller / Fungal Genetics and Biology xxx (2013) xxx–xxx 7

538 Talbot, 2007). Following germination on the leaf surface, a of germinating conidia and germlings by non-professional 604 539 dome-shaped appresorium develops at the end of the germ tube. phagocytes has recently been shown to be important for pathogen- 605 540 G-protein, cAMP-PKA, and Pmk1 MAPK signaling are required for esis. During isotropic conidial swelling, b-(1,3)-glucan moieties on 606 541 appressorium formation (Nishimura et al., 2003; Mitchell and Dean, the surface of A. fumigatus conidia become exposed and bind to 607 542 1995; Xu and Hamer, 1996). As the appressorium matures, dihydr- dectin-1 receptors on type II pneumocytes. This binding event acti- 608 543 oxynapthalene melanin and chitin is deposited on the cell wall to vates phospholipase D, which induces internalization of the swol- 609 544 provide structural support against high turgor pressure required len conidia into the epithelial cell (Han et al., 2011). In addition to 610 545 for penetration (Wilson and Talbot, 2009). Turgor pressure (up to dectin-1, E-cadherin on type II pneumocytes can mediate internal- 611 546 8.0 MPa) is generated by rapid uptake of water driven by elevated ization of A. fumigatus conidia (Xu et al., 2012). Following their 612 547 intracellular glycerol concentrations (Wang et al., 2005). Elevation interaction with epithelial cells, Aspergillus spp. frequently invade 613 548 in turgor pressure forces a penetration peg through a fungal pore blood vessels resulting in thrombosis and disseminated disease. 614 549 that lacks a cell wall to facilitate entry into the plant cell. Penetra- In vitro modeling shows that A. fumigatus hyphae directly pene- 615 550 tion peg formation is governed by Mps1 MAPK signaling and reac- trate the endothelial cell when growing towards the lumen of 616 551 tive oxygen species generated by NADPH oxidases Nox1, Nox2 and the blood vessel (abluminal invasion) or when the hyphal tip con- 617 552 NoxR (Xu et al., 1998; Ryder et al., 2013). Both MAPK signaling and tacts the luminal side of the endothelial cell (luminal invasion) 618 553 reactive oxygen species promote formation of a heteroligomeric (Kamai et al., 2009). Thus, angioinvasion by Aspergillus is a trans- 619 554 septin ring (Sep3, Sep4, Sep5, Sep6), which functions as a scaffold cellular and not a paracellular process. Moreover, endothelial cell 620 555 for F-actin at the penetration pore and acts as a diffusion barrier invasion induces production of TNF-a and tissue factor, which 621 556 for proteins involved in membrane evagination (i.e. penetration are involved in inflammation and thrombosis, respectively (Kamai 622 557 peg) (Dagdas et al., 2012). Following proper migration of nuclei, et al., 2009). Endothelial cell invasion likely contributes to the angi- 623 558 mitosis, and penetration into the plant host, the conidium on the oinvasive properties of Rhizopus oryzae, the most common agent of 624 559 plant surface undergoes autophagic death. Autophagy, which is crit- mucormycosis. Following binding of GRP78 on the endothelial cell 625 560 ical for invasion and virulence, begins shortly after germination, oc- surface, R. oryzae germlings are internalized and damage the cell 626 561 curs in both conidium and appressorium, requires Pmk1 MAP kinase (Liu et al., 2010). Expression of this receptor is upregulated in 627 562 activity, promotes maturation of the appressorium, and induces brain, sinus, and lung tissues during experimental diabetic ketoac- 628 563 conidial cell death (Kershaw and Talbot, 2009). idosis (serum pH < 7.4, elevated iron, and hyperglycemia) (Liu 629 564 Following invasion of the plant cell, differentiation of the pene- et al., 2010). These data provide insight into mechanisms used by 630 565 tration peg is influenced by the lifestyle of the infecting fungus. For Aspergillus and Rhizopus oryzae to invade tissues commonly dam- 631 566 obligate biotrophs, the penetration peg matures into a specialized aged in patients with invasive aspergillosis and diabetic ketoacido- 632 567 infection structure known as haustorium, which is surrounded by sis, respectively. On the basis of studies in A. fumigatus and other 633 568 the plant cell membrane and facilitates uptake of nutrients. For opportunistic human pathogens such as Candida albicans and Cryp- 634 569 hemibiotrophs, the penetration peg swells to form an infection tococcus neoformans (Filler, 2013), the mechanisms used by cross- 635 570 vesicle from which large, biotrophic primary hyphae emerge to in- over fungi to invade tissues are likely to be diverse. 636 571 fect the first (epidermal) or second (mesophyll) cell layers under- For several human fungal pathogens, the ability to assimilate 637 572 neath the cuticle. After a period of biotrophic growth (12–48 h), nutrients such as iron contributes to pathogenesis; this is also 638 573 narrow necrotrophic (secondary) hyphae emerge from the primary true for plant pathogenic fungi as well as symbiotic fungi 639 574 hyphae to kill plant cells (Perfect et al., 1999). The transition be- (reviewed in Haas et al., 2008). In A. fumigatus, virulence has been 640 575 tween appressorial development to biotrophic growth to necro- linked to siderophore-mediated iron uptake and metabolic 641 576 trophic plant cell destruction involves substantial changes in reprogramming of the fungal cell in response to iron limitation. 642 577 gene transcription, which has recently been characterized in Collet- Deletion of A. fumigatus genes involved with siderophore biosyn- 643 578 otrichium species. In C. graminicola and C. higginsianum, 22% and thesis results in attenuated or complete loss of virulence in a 644 579 44% of genes are differentially expressed during infection murine model of infection (Schrettl et al., 2007, 2004). Crossover 645 580 (O’Connell et al., 2012). Genes encoding carbohydrate active en- pathogens A. flavus, A. niger, and F. oxysporum also produce 646 581 zymes involved with cutin, cellulose, hemicellulose, and pectin siderophores; however, their role in pathogenesis remains unex- 647 582 degradation are upregulated during appressorium maturation, plored (Baakza et al., 2004; López-Berges et al., 2013). Sidero- 648 583 whereas gene encoding secreted proteases are highly expressed phore biosynthesis contributes to virulence in plant pathogens 649 584 during the necrotrophic growth (O’Connell et al., 2012). Transcrip- C. heterostrophus, Cochliobolus miyabeanus, Fusarium graminearum, 650 585 tion of secondary metabolite gene clusters is highest during and Alternaria brassicicola (Oide et al., 2006). The bZIP transcrip- 651 586 appressorial and biotrophic phases, and substantially declines dur- tion factor, HapX, in A. fumigatus and F. oxysporum facilitates 652 587 ing necrotophy. Genes encoding secreted effector proteins are adaptation to iron poor conditions related to sequestration by 653 588 highly transcribed during biotrophic growth. This transcriptional iron-binding molecules (e.g. ferritin, transferrin, lactoferrin) in 654 589 pattern suggests secondary metabolites in addition to secreted the human body. HapX functions as part of transcription factor 655 590 effector proteins alter or impair the host response to infection to complex that inhibits iron-consuming metabolic pathways, 656 591 facilitate invasion and biotrophic growth (O’Connell et al., 2012). refashions the intracellular amino acid pool, and represses SreA 657 592 Deep fungal infection in humans results in substantial morbid- (a negative regulator of siderophore biosynthesis) to promote 658 593 ity and mortality due to invasion and subsequent necrosis of lung, growth when exogenous iron is limited (Schrettl et al., 2010; 659 594 ocular, brain, vascular, and cutaneous tissues (Table 2). The contri- López-Berges et al., 2013). A. fumigatus and F. oxysporum HapX 660 595 bution of specialized infection structures used by some crossover null mutants are avirulent in murine models of pulmonary and 661 596 pathogens (e.g. Collectotrichum appressoria) for invasion of human systemic infection, respectively (Schrettl et al., 2010; López-Ber- 662 597 tissue is unknown. Tissue destruction (e.g. collagen, elastin) and ges et al., 2013). Moreover, deletion of HapX in F. oxysporum re- 663 598 invasion during infection is postulated to occur through secreted duces the ability of this pathogen to cause disease in tomato 664 599 enzymes and invasion of host cells (e.g. epithelial, endothelial). plants and compete for iron against siderophore-producing bacte- 665 600 As mentioned above, deciphering the role of degradative enzymes ria (Pseudomonas spp.) that reside on the root surface (López-Ber- 666 601 on virulence has been complicated by functional redundancy, how- ges et al., 2013). Collectively these data suggest that adaptation to 667 602 ever such enzymes are essential for the fungus to obtain nutrients iron limitation and regulation of iron homeostasis are important 668 603 (Abad et al., 2010; Mellon et al., 2007). Receptor-mediated uptake for fungal infection of mammals and plants. 669

8 G.M. Gauthier, N.P. Keller / Fungal Genetics and Biology xxx (2013) xxx–xxx

670 Although not as well studied as iron, a requirement for other 96% (Smith et al., 2012). Crossover fungi isolated from clinical 733 671 metals including copper and zinc has been demonstrated for both specimens include E. rostratum, A. alternata, Bipolaris spp., and 734 672 human and plant pathogenic fungi. Copper is an essential co-factor Cladosporium cladosporioides (CDC; Smith et al., 2012; Lockhart 735 673 for several enzymes such as laccases, oxidases and dismutases et al., 2013). 736 674 (Mäkelä et al., 2013; Hwang et al., 2002). Work in Cryptococcus neo- Although smaller in scale than the current fungal meningitis 737 675 formans and Candida albicans have demonstrated the critical need outbreak, there have been several reports of crossover fungal out- 738 676 for homeostasis in maintaining appropriate amounts of copper breaks. In 2000–2001, five women were diagnosed with Curvularia 739 677 during pathogenesis (Waterman et al., 2013; Ding et al., 2011, lunata infection involving saline filled breast implants following 740 678 2013; Hwang et al., 2002). Zinc is a common co-factor for many augmentation mammoplasty (Kainer et al., 2005). The likely source 741 679 regulator genes (e.g. zinc fingers and zinc cluster proteins). A novel of infection was environmental contamination of saline prior to 742 680 uptake system has been recently described in C. albicans (Citiulo injection into the implants. Improper airflow in the operating 743 681 et al., 2012) and zinc deprivation leads to poor growth of fungi room, use of an ‘‘open bowl’’ technique (saline poured into an 744 682 (Lulloff et al., 2004). Several studies in A. fumigatus have demon- uncovered, sterile bowl), and fungal contamination of a water- 745 683 strated a requirement for zinc uptake in pathogenesis (reviewed damaged ceiling in the sterile supply room were associated with 746 684 in Wilson et al., 2012) and, as the genes involved are conserved infection of the saline implants (Kainer et al., 2005). In 2005– 747 685 in fungi, it is likely a similar system is required for pathogenesis 2006, a large outbreak of F. solani and F. oxysporum keratitis oc- 748 686 in most if not all fungi. This ability of fungi to uptake these metals curred in the USA and other countries affecting >300 people (Chang 749 687 is being exploited in bioremediation programs (Hong et al., 2010). et al., 2006; Grant and Fridkin, 2007; Mukherjee et al., 2012). This 750 688 The 2005 – 2006 outbreak of contact lens associated Fusarium outbreak was associated with use of ReNu with MoistureLoc con- 751 689 keratitis highlighted the importance of crossover pathogens to tact lens solution, which has been withdrawn from the market 752 690 medical and plant pathology communities. Multilocus sequence (Chang et al., 2006; Grant and Fridkin, 2007). In contrast to the fun- 753 691 typing identified a subgroup of clinical isolates belonging to F. gal meningitis outbreak, the medical product was sterile at the 754 692 solani species complex group 1 (FSSC 1) were the same species as time it was manufactured. Fusarium contamination occurred in 755 693 F. solani f. sp. cucurbitae race 2 (Fsc2), which infects squashes the patients’ local environment and involved opened bottles and 756 694 (Zhang et al., 2006; Mehl and Epstein, 2007). Subsequent investiga- used contact lens cases (Chang et al., 2006). Potential factors con- 757 695 tion of a different group of FSSC 1 isolates from clinical specimens, tributing to the development of keratitis included reduced biocide 758 696 sewage, and plants demonstrated they are all capable of infecting efficacy due to its uptake by the contact lens material, nutritive 759 697 zucchini, reproducing with the opposite mating type, and growing properties of lens solution, biofilm formation (F. solani > F. oxyspo- 760 698 at 37 °C(Mehl and Epstein, 2007). In addition to FSSC 1, F. oxysporum) on contact lens surface, and chemical damage to the cornea 761

699 rum f. sp. lycopersici race 2 (referred to as F. oxysporumlr2), can related to biocides in the contact lens (Epstein, 2007; Mukherjee 762 700 cause disseminated, fatal infection in a murine model and kill to- et al., 2012). Penetrating trauma related to natural disasters includ- 763 701 mato plants (Ortoneda et al., 2004). Plant and human Fusarium ing a volcanic eruption in Columbia in 1985 and an EF-5 tornado in 764 702 solani and oxysporum isolates are also capable of killing Galleria Joplin, Missouri in 2011 have resulted in outbreaks of mucormyco- 765 703 mellonella larvae (greater wax moth), a model invertebrate host sis (Patiño et al., 1991; Fanfair et al., 2012). Similarly, combat-re- 766 704 (Coleman et al., 2011; Navarro-Velasco et al., 2011). These findings lated blast injuries in Afghanistan and Iraq have resulted in 767 705 have positioned Fusarium to become a model crossover pathogen severe fungal infections (Warkentien et al., 2012; Paolino et al., 768 706 for investigating the genetics underlying shared (and host specific) 2012). Crossover pathogens recovered from infected tissue include 769 707 mechanisms of pathogenesis in plants and mammals. Deletion of a Mucor spp., A. flavus, A. niger, Acrophialophora fusispora, Alternaria 770 708 G-protein b subunit (Fgb1) and fmk1 MAP kinase (Fmk1) impairs spp., Bipolaris spp., Fusarium spp., and Ulocladium spp. (Warkentien 771

709 the ability of F. oxysporumlr2 DFgb1/DFmk1 to bind ﬁbronectin, se- et al., 2012). In addition to contamination of blast injury site with 772 710 crete proteases and kill mice (Prados-Rosales et al., 2006). Simi- organic material, other risk factors included systemic acidosis and 773

711 larly, F. oxysporumlr2 VeA and LaeA null mutants have attenuated large transfusion requirements (average of 30 units of red blood 774 712 virulence in mice and are unable to biosynthesize the mycotoxin cells or fresh frozen plasma per patient), which can result in immu- 775 713 beauvericin when grown in human blood (López-Berges et al., nosuppression and iron overload (Warkentien et al., 2012). 776 714 2013). These findings are significant because Fgb1, Fmk1, VeA, These outbreaks highlight several important events that can lead 777 715 LaeA and HapX also contribute to virulence in plants (e.g. tomato to infection by crossover pathogens: (i) penetration of the protective 778 716 plants). barriers—direct inoculation of fungi into the cornea, epidural space, 779 subcutaneous tissue, joint, and medical devices; (ii) immunosup- 780 pression; (iii) thermotolerance; (iv) environmental contamination 781 717 5. Crossover fungi outbreaks of medicines, solutions, and tissue; and (v) and the ability of fungi 782 to acquire host-derived nutrients to facilitate growth and invasion 783 718 The outbreak of fungal meningitis associated with contami- of tissue (Table 2). 784 719 nated lots of methylprednisolone acetate used for epidural and in- 720 tra-articular injections is unprecedented in scope. As of June 2013, 721 745 patients from 20 states have met the Centers for Disease Con- 6. Toxins, mycotoxins and mycotoxicosis 785 722 trol case definition and 58 people have died (7.8% mortality) (CDC). 723 Clinical manifestations include meningitis, isolated paraspinal A subset of fungi produce toxic secondary metabolites termed 786 724 infection (i.e. epidural abscess, discitis, vertebral osteomyelitis, mycotoxins that when ingested can result in human disease collec- 787 725 arachnoiditis, phlegmon), meningitis with paraspinal infection, tively known as mycotoxicoses (Wild and Gong, 2010). Most of 788 726 and septic arthritis (CDC). Histopathologic analysis has demon- these fungi are facultative parasites that exist as saprophytes but 789 727 strated fungal invasion of the brain, leptomeningeal, and vascular also cause diseases of edible parts of the plant. The majority of 790 728 tissues (CDC; Bell et al., 2013). Central nervous system vascular the common mycotoxins are produced by Aspergillus, Fusarium, 791 729 invasion has been characterized by inflammation (vasculitis), Penicillium and Claviceps spp. (for reviews, the reader is directed 792 730 thrombosis, and hemorrhage (CDC; Bell et al., 2013). An estimated to Subramaniam and Rampitsch, 2013; Woloshuk and Shim, 793 731 9% of patients with fungal meningitis have experienced stroke with 2013). In some cases the mycotoxin, such as trichothecenes pro- 794 732 involvement of the posterior or brainstem circulation occurring in duced by F. graminearum (Proctor et al., 1995; Menke et al., 795

G.M. Gauthier, N.P. Keller / Fungal Genetics and Biology xxx (2013) xxx–xxx 9

796 2012), is a virulence factor in plant disease development but in which are the intended targets of agricultural fungicides, are in a 859 797 general, production of the mycotoxin does not appear to unique position to develop resistance, which has the potential to 860 798 exacerbate plant disease. The different mycotoxins produce a limit therapeutic options for treating these pathogens in humans. 861 799 plethora of symptoms in humans and other mammals that can lead The potential impact of fungicides on clinically significant resis- 862 800 to death, as is the case for A. flavus aflatoxin poisoning of both ani- tance in crossover pathogens remains speculative and is an area 863 801 mals and humans (Wouters et al., 2013; Dereszynski et al., 2008; for future research. 864 802 Lewis et al., 2005; Lye et al., 1995). Interestingly, several mycotox- 803 igenic fungi are also human pathogens such as A. flavus; however it 8. Allergic inflammation and crossover pathogens 865 804 is rare to find reports of mycotoxin synthesis in human tissues by 805 the invading fungi (Mori et al., 1998). Whether this is due to lack of Another area where fungi play a large role in human health is 866 806 synthesis in situ or failure to analyze patient tissues for mycotoxins allergenicity where several fungal species elicit severe inflamma- 867 807 is unknown. tion responses in a largely non-invasive manner, although local 868 808 While not classified as mycotoxins, several other fungal toxins colonization of lung epithelial tissues may be important in contin- 869 809 are known or suspected to participate in disease development in uing allergenic challenge. Aspergillus fumigatus and Alternaria spp. 870 810 both plants and animals (including humans). Many of the plant dis- are particularly allergenic but other fungi, including several cross- 871 811 eases caused by Dothideomycete fungi (e.g. Cochliobolus, Alternaria) over spp. can and do play a role in the allergic response. It is be- 872 812 are exacerbated by the production of phytotoxins, which can be yond the scope of this current review to address this topic 873 813 host-specific, or non-host specific (reviewed in Stergiopoulos however, and the reader is referred to several recent reviews on 874 814 et al., 2013). A. fumigatus, which is responsible for the majority of this topic (Callejas and Douglas, 2013; Mahdavinia and Grammer, 875 815 invasive aspergillosis (IA) cases, produces many toxins thought to 2012; Kennedy et al., 2012; Knutsen et al., 2012; Chaudhary and 876 816 contribute to IA (Yin et al., 2013; Dagenais and Keller, 2009; Gauthi- Marr, 2011). 877 817 er et al., 2012). The Velvet complex and LaeA, mentioned earlier, are 818 global regulators of toxin production in fungi and have been found 9. Conclusion 878 819 to be virulence factors in both plant and human pathogenic fungi 820 (Amaike and Keller, 2009; Wiemann et al., 2010; Wu et al., 2012; Although not common, IFI from crossover fungi are not infre- 879 821 Yang et al., 2013). It is notable that many of the fungi listed in Table quent and appear to be on the rise. This latter observation is likely 880 822 1 are known toxin producers; however any possible impact of toxin associated with the increased numbers of immunocompromised 881 823 synthesis in human infection has not been explored. patients world wide. Infections are also frequently associated with 882 injuries or contamination of medical apparati or medicines. How- 883 ever, not all fungi have the capability to crossover; certain proper- 884 824 7. Agricultural fungicides and invasive fungal infections in ties such as the ability to grow at 37 °C are necessary for robust 885 825 humans infections. A close look at the fungi listed in Table 1 shows that 886 many of the crossover fungi are dematiaceous fungi. Many of these 887 826 To minimize agricultural losses from fungal diseases, fungicides dematiaceous fungi are weak plant pathogens and can survive well 888 827 are routinely applied to economically valuable crops. In 2007, an as saprophytes. Possibly it is some of the properties that allow for 889 828 estimated $8 billion was spent on fungicides worldwide (Knight saprophytic growth that give them an edge in opportunistic infec- 890 829 and Turner, 2009). Expenditures in the United States, European Un- tions of humans. Regardless of the properties allowing for cross- 891 830 ion, and United Kingdom were $800 million, $2.9 billion, and over, once infection occurs many of the same virulence factors 892 831 $272 million, respectively (Knight and Turner, 2009; Osteen are shared between plant and human pathogenic fungi. 893 832 et al., 2012). Although controversial, there is concern that exten- 833 sive use of agricultural triazoles can induce the resistance of A. References 894 834 fumigatus to medically important triazoles such as itraconazole, 835 voriconazole, and posaconazole (Snelders et al., 2009, 2012; Ver- Abad, A. et al., 2010. What makes Aspergillus fumigatus a successful pathogen? 895 836 weij et al., 2009). Genes and molecules involved in invasive aspergillosis. Rev. Iberoam. Micol. 27, 896 897 837 In the Netherlands, the prevalence of itraconazole resistance of 155–182. Aimanianda, V. et al., 2009. Surface hydrophobin prevents immune recognition of 898 838 A. fumigatus isolated from humans has increased from 1.7% to 6.0%, airborne fungal spores. Nature 460, 1117–1121. 899 839 and 90% to 94% of these resistant isolates contain a 34-base pair Almaguer, M. et al., 2013. Effect of temperature on growth and germination of 900 conidia in Curvularia and Bipolaris species isolated from the air. Aerobiologia 29, 901 840 tandem repeat and a point mutation in cyp51A (TR34/L98H muta- 13–20. 902 841 tion) (Snelders et al., 2008; van der Linden et al., 2011). Cyp51A en- Amaike, S., Keller, N.P., 2009. Distinct roles for VeA and LaeA in development and 903 842 codes 14-a-lanosterol demethylase, which is involved in ergosterol pathogenesis of Aspergillus flavus. Eukaryot. Cell 8, 1051–1060. 904 Anderson, R.D. et al., 2013. Discriminating fever behavior in house flies. PLoS ONE 8, 905 843 biosynthesis and inhibited by triazole antifungals. The TR34/L98H e62269. 906 844 mutant also confers reduced susceptibility or resistance to vorico- Araujo, R., Rodrigues, A.G., 2004. Variability of germinative potential among 907 845 nazole and posaconazole (Snelders et al., 2008, 2011). A. fumigatus pathogenic species of Aspergillus. J. Clin. Microbiol. 42, 4335–4337. 908 Au, D.W.T. et al., 1996. The role of mucilage in the attachment of conidia, germ 909 846 TR34/L98H mutants are not just found in the Netherlands, but have tubes, and appresoria in the saprobic aquatic hyphomycetes Lemonniera aquatic 910 847 also been isolated from humans in several other European coun- and Mycocentrospora foliformis. Can. J. Bot. 74, 1789–1800. 911 848 tries and Asia (Lockhart et al., 2011; van der Linden et al., 2013). Baakza, A. et al., 2004. A comparative study of siderophore production by fungi from 912 913 849 TR34/L98H mutants are derived from a common ancestor and iso- marine and terrestrial habitats. J. Exp. Mar. Biol. Ecol. 311, 1–9. Bagga, S., Straney, D., 2000. Modulation of cAMP and phosphodiesterase activity by 914 850 lates recovered from cultivated soils are genetically linked to clin- flavonoids which induce spore germination of Nectria haematoccocca MP VI 915 851 ical A. fumigatus isolates harboring the TR34/L98H mutation (Fusarium solani). Physiol. Mol. Plant Pathol. 56, 51–61. 916 852 (Snelders et al., 2009; Mortensen et al., 2010; Camps et al., 2012). Barhoom, S., Sharon, A., 2004. CAMP regulation of ‘‘pathogenic’’ and ‘‘saprophytic’’ 917 918 853 The spread of TR /L98H in Europe, emergence of novel A. fungal spore germination. Fungal. Genet. Biol. 41, 317–326. 34 Bayram, O. et al., 2008. VelB/VeA/LaeA complex coordinates light signal with fungal 919 854 fumigatus mutants with high-level voriconazole resistance (TR46/ development and secondary metabolism. Science 320, 1504–1506. 920 855 Y121F/T289A), and widespread use of agricultural triazoles with Bell, W.R. et al., 2013. Iatrogenic Exserohilum infection of the central nervous 921 922 856 activity against A. fumigatus have the potential to adversely affect system: mycological identification and histopathological findings. Mod. Pathol. 26, 166–170. 923 857 clinical outcomes in patients with invasive aspergillosis (Snelders Bergman, A., Casadevall, A., 2010. Mammalian endothermy optimally restricts fungi 924 858 et al., 2012; van der Linden et al., 2013). Crossover pathogens, and metabolic costs. MBio 1, e00212-10. 925

10 G.M. Gauthier, N.P. Keller / Fungal Genetics and Biology xxx (2013) xxx–xxx

926 Bitar, D. et al., 2009. Increasing incidence of zygomycosis (mucormycosis), France, Gil, M.L. et al., 1996. Binding of extracellular matrix proteins to Aspergillus fumigatus 1012 927 1997–2006. Emerg. Infect. Dis. 2009 (15), 1395–1401. conidia. Infect. Immun. 64, 5239–5247. 1013 928 Blackwell, M., 2011. The fungi: 1, 2, 3 ...5.1 million species. Am. J. Bot. 98, 426–438. Gomes, M.Z.R., et al., 2011. Mucormycosis caused by unusual mucormycetes, non- Q6 1014 929 Blehert, D.S., 2012. Fungal disease and the developing story of bat white-nose Rhizopus, -Mucur, and –Lichtheimia species. 24, 411–445. 1015 930 syndrome. PLoS. Pathog. 8, e1002779. Grant, G.B., Fridkin, S., 2007. Postrecall surveillance following a multistate Fusarium 1016 931 Boeuf, S. et al., 2012. Engineering hydrophobin DewA to generate surfaces that keratitis outbreak, 2004 through 2006. JAMA 298, 2867–2868. 1017 932 enhance adhesion of human but not bacterial cells. Acta Biomater. 8, 1037– Haas, H. et al., 2008. Siderophores in fungal physiology and virulence. Annu. Rev. 1018 933 1047. Phytopathol. 2008 (46), 149–187. 1019 934 Bouchara, J.P. et al., 1996. Attachment of spores of the human pathogenic fungus Hamer, J.E. et al., 1988. A mechanism for surface attachment in spores of a plant 1020 935 Rhizopus oryzae to extracellular matrix components. Eur. J. Cell. Biol. 70, 76–83. pathogenic fungus. Science 239, 288–290. 1021 936 Breth, B. et al., 2013. The role of the Tra1p transcription factor of Magnaporthe Han, X. et al., 2011. b-1,3-glucan-induced host phospholipase D activation is 1022 937 oryzae in spore adhesion and pathogenic development. Fungal. Genet. Biol. involved in Aspergillus fumigatus internalization into type II human pneumocyte 1023 938 (Epub ahead of print). A549 cells. PLoS ONE 6, e21468. 1024 939 Brown, G.D. et al., 2012. Hidden Killers: human fungal infections. Sci. Transl. Med. 4, Hawksworth, D.L., Rossman, A.Y., 1997. Where are all the undescribed fungi? 1025 940 165rv13. Phytopathology 87, 888–891. 1026 941 Callejas, C.A., Douglas, R.G., 2013. Fungal Rhinosinusitis: what every allergist should Hernández, O. et al., 2012. The hydrolase PbHAD32 participates in the adherence of 1027 942 know. Clin. Exp. Allergy. 43, 835–849. Paracoccidioides brasiliensis conidia to epithelial lung cells. Med. Mycol. 50, 533– 1028 943 Camps, S.M.T. et al., 2012. Molecular epidemiology of Aspergillus fumigatus isolates 537. 1029 944 harboring the TR34/L98H azole resistance mechanism. J. Clin. Microbiol. 50, Hiruma, M., Kagawa, S., 1986. Effects of hyperthermia on phagocytosis and 1030 945 2674–2680. intracellular killing of Sporothrix schenckii by polymorphonuclear leukocytes. 1031 946 Caracuel-Rios, Z., Talbot, N.J., 2007. Cellular differentiation and host invasion by the Mycopathologia 95, 93–100. 1032 947 rice blast fungus Magnaporthe grisea. Curr. Opin. Microbiol. 10, 339–345. Hiruma, M. et al., 1993. Hyperthermic treatment of chromoblastomycosis with 1033 948 Casadevall, A., 2005. Fungal virulence, vertebrate endothermy, and dinosaur disposable chemical pocket warmers. Mycopathologia 122, 107–114. 1034 949 extinction: is there a connection? Fungal. Genet. Biol. 42, 98–106. Holmes, G.J., 2002. Influence of wound type and storage duration on susceptibility 1035 950 Casadevall, A., 2012. Fungi and the rise of mammals. PLoS. Pathog. 8, e1002808. of sweetpotatoes to Rhizopus soft rot. Plant Dis. 86, 345–348. 1036 951 CDC: http:// cdc.gov/hai/outbreaks/laboratory/lab_testing_results.html. (accessed Hong, J.W. et al., 2010. Pyrene degradation and copper and zinc uptake by Fusarium 1037 952 June, 2013). solani and Hypocrea lixii isolated from petrol station soil. J. Appl. Microbiol. 108, 1038 953 Chaky, J. et al., 2001. Surface hydrophobicity and surface rigidity induce spore 2030–2040. 1039 954 germination in Colletotrichum graminicola. Phytopathology 91, 558–564. Horbach, R. et al., 2011. When and how to kill a plant cell: infection strategies of 1040 955 Chang, D.C. et al., 2006. Multistate outbreak of Fusarium keratitis associated with plant pathogenic fungi. J. Plant Physiol. 168, 51–62. 1041 956 use of a contact lens solution. JAMA 296, 953–963. Horst, R.K., 2008. Westcott’s Plant Disease Handbook, seventh ed. Springer-Verlag, 1042 957 Chatfield, M.W., Richards-Zawacki, C.L., 2011. Elevated temperature as a treatment Berlin Heidelbert, New York. 1043 958 for Batrachohytrium dendrobatidis infection in captive frogs. Dis. Aquat. Org. 94, Hunt, V.L., Charnley, A.K., 2011. The inhibitory effect of the fungal toxin, destruxin 1044 959 235–238. A, on behavioral fever in the desert locust. J. Insect. Physiol. 57, 1341–1346. 1045 960 Chaudhary, N., Marr, K.A., 2011. Impact of Aspergillus fumigatus in allergic airway Hwang, C.S. et al., 2002. Copper- and zinc-containing superoxide dismutase (Cu/ 1046 961 diseases. Clin. Transl. Allergy. 1, 4. ZnSOD) is required for the protection of Candida albicans against oxidative 1047 962 Citiulo, F. et al., 2012. Candida albicans scavenges host zinc via Pra1 during stresses and the expression of its full virulence. Microbiology 148, 3705–3713. 1048 963 endothelial invasion. PLoS Pathog. 8, e1002777. Ibrahim, A.S., 2011. Host cell invasion in mucormycosis: role of iron. Curr. Opin. 1049 964 Coleman, J.J. et al., 2011. Fusarium pathogenesis investigated using Galleria Microbiol. 14, 406–411. 1050 965 mellonella as a heterologous host. Fungal. Biol. 115, 1279–1289. Imazaki, I. et al., 2007. Fow2, a Zn(II)2Cys6-type transcription regulator, controls 1051 966 Czymmek, K.J. et al., 2007. In vivo time-lapse documentation using confocal and plant infection of the vascular wild fungus Fusarium oxysporum. Mol. Microbiol. 1052 967 multi-photon microscopy reveals the mechanisms of invasion into the 63, 737–753. 1053 968 Arabidopsis root vascular system by Fusarium oxysporum. Fungal. Genet. Biol. Jain, S. et al., 2003. The G protein subunit FGB1 regulates development and 1054 969 44, 1011–1023. pathogenicity of Fusarium oxysporum. Curr. Genet. 43, 79–86. 1055 970 Dagdas, Y.F. et al., 2012. Septin-mediated plant cell invasion by the rice blast Jonkers, W. et al., 2009. Impaired colonization and infection of tomato roots by the 1056 971 fungus, Magnaporthe oryzae. Science 336, 1590–1595. frp1 mutant of Fusarium oxysporum correlates with reduced CWDE gene 1057 972 Dagenais, T.R., Keller, N.P., 2009. Pathogenesis of Aspergillus fumigatus in invasive expression. Mol. Plant Microb. Interact. 22, 507–518. 1058 973 aspergillosis. Clin. Microbiol. Rev. 22, 447–465. Kainer, M.A. et al., 2005. Saline-filled breast implant contamination with Curvularia 1059 974 Dagenais, T.R. et al., 2010. Aspergillus fumigatus LaeA-mediated phagocytosis is species among women who underwent cosmetic breast implantation. J. Infect. 1060 975 associated with a decreased hydrophobin layer. Infect. Immun. 78, 823– Dis. 192, 170–177. 1061 976 829. Kainer, M.A. et al., 2012. Fungal infections associated with contaminated 1062 977 Dereszynski, D.M. et al., 2008. Clinical and clinicopathologic features of dogs that methylprednisolone in Tennessee. N. Engl. J. Med. 367, 2194-2103. 1063 978 consumed foodborne hepatotoxic aflatoxins: 72 cases (2005–2006). J. Am. Vet. Kamai, Y. et al., 2009. Polarized response of endothelial cells to invasion by 1064 979 Med. Assoc. 232, 1329–1337. Aspergillus fumigatus. Cell. Microbiol. 11, 170–182. 1065 980 Dickman, M.B., de Figueiredo, P., 2011. Comparative pathobiology of fungal Karimi-Aghcheh R., et al. 2013. Functional analyses of Trichoderma reesei Lae1 1066 981 pathogens of plants and animals. PLoS. Pathog. 7, e1002324. reveal conserved and contrasting roles of this regulator. G3 3:369–378. 1067 982 Dignani, M.C., Anaissie, E., 2004. Human fusariosis. Clin. Microbiol. Infect. 10 (suppl. Kauffman, C.A. et al., 2007. Clinical practice guidelines for the management of 1068 983 1), 67–75. sporotrichosis: 2007 update by the Infectious Diseases Society of America. Clin. 1069 984 Ding, C. et al., 2011. The copper regulon of the human fungal pathogen Cryptococcus Infect. Dis. 45, 1255–1265. 1070 985 neoformans H99. Mol. Microbiol. 81, 1560–1576. Kennedy, J.L. et al., 2012. The role of allergy in severe asthma. Clin. Exp. Allergy 42, 1071 986 Ding, C. et al., 2013. Cryptococcus neoformans copper detoxification machinery is 659–669. 1072 987 critical for fungal virulence. Cell. Host. Microbe. 13, 265–276. Kershaw, M.J., Talbot, N.J., 2009. Genome-wide functional analysis reveals that 1073 988 Divon, H.H. et al., 2006. The global nitrogen regulator, FNR1, regulates fungal infection-associated fungal autophagy is necessary for rice blast disease. Proc. 1074 989 nutrition-genes and fitness during Fusarium oxysporum pathogenesis. Mol. Plant Natl. Acad. Sci. USA 106, 15967–15972. 1075 990 Pathol. 7, 485–497. Kessel, L. et al., 2010. The relationship between body and ambient temperature and 1076 991 Do, J.H. et al., 2009. Exploring temporal transcriptional regulation structure of corneal temperature. Invest. Ophthalmol. Vis. Sci. 51, 6593–6597. 1077 992 Aspergillus fumigatus in heat shock by state space model. BMC Genomics. 10, Kim, Y.K. et al., 1998. Induction of Ca2+-calmodulin signaling by hard-surface 1078 993 306. contact primes Colletotrichum gloeosporioides conidia to germination and form 1079 994 Dominguez, E. et al., 2011. An overview on plant cuticle biomechanics. Plant Sci. appressoria. J. Bactriol. 180, 5144–5150. 1080 995 181, 77–84. Kim, Y.K. et al., 2002. Identification of a hard surface contact-induced gene in 1081 996 Dong, X. et al., 2005. Roles of adherence and matrix metalloproteinases in growth Colletotrichum gloeosporioides conidia as a sterol glycosyl transferase, a novel 1082 997 patterns of fungal pathogens in cornea. Curr. Eye Res. 30, 613–620. fungal virulence factor. Plant J. 30, 177–187. 1083 998 Dong, X. et al., 2012. Fusaric acid is a crucial factor in the disturbance of leaf water Knight, B., Turner, R., 2009. Topic No 1 – agrochemical resistance: fungicides in 1084 999 imbalance in Fusarium-infected banana plants. Plant Physiol. Biochem. 60, 171– combinable crops in the UK. Report on economic, financial and market studies 1085 1000 179. to demonstrate the economic value of research carried out by Rothamsted 1086 1001 Epstein, A.B., 2007. In the aftermath of the Fusarium keratitis outbreak: what have Research. 1087 1002 we learned? Clin. Ophthalmol. 1, 355–366. Knutsen, A.P. et al., 2012. Fungi and allergic lower respiratory tract diseases. J. 1088 1003 Fanfair, R.N. et al., 2012. Necrotizing cutaneous mucormycosis after a tornado in Allergy Clin. Immunol. 129, 280–291. 1089 1004 Joplin, Missouri, in 2011. N. Engl. J. Med. 367, 2214–2225. Kontoyiannis, D.P. et al., 2010. Prospective surveillance for invasive fungal 1090 1005 Filler, S.G., 2013. Can host receptors for fungi be targeted for treatment of fungal infections in hematopoietic stem cell transplant recipients, 2001–2006: 1091 1006 infections? Trends Microbiol. 21, 389–396. overview of the transplant-associated infection surveillance network 1092 1007 Ganem, S. et al., 2004. G-protein subunit of Cochliobolus heterostrophus involved in (TRANSNET) database. Clin. Infect. Dis. 50, 1091–1100. 1093 1008 virulence, asexual and sexual reproductive ability, and morphogenesis. Kozubowski, L. et al., 2009. Signaling pathways in the pathogenesis of Cryptococcus. 1094 1009 Eukaryot. Cell 6, 1653–1663. Cell Microbiol. 11, 370–380. 1095 1010 Gauthier, T. et al., 2012. Trypacidin, a spore-borne toxin from Aspergillus fumigatus, Krishnam, S. et al., 2009. Aspergillus flavus: an emerging non-fumigatus species of 1096 1011 is cytotoxic to lung cells. PLoS ONE 7, e29906. significance. Mycoses 52, 206–222. 1097

G.M. Gauthier, N.P. Keller / Fungal Genetics and Biology xxx (2013) xxx–xxx 11

1098 Kwon, Y.H., Epstein, L., 1997. Involvement of a 90 kDa glycoprotein in adhesion of Nanguy, S.P.M. et al., 2010. Impact of water activity of diverse media on spore 1184 1099 Nectia haematococca macroconidia. Physiol. Mol. Plant Pathol. 51, 287–303. germination of Aspergillus and Pencillium speces. Int. J. Food. MIcrobiol. 142, 1185 1100 Lamarre, C. et al., 2008. Transcriptomic analysis of the exit from dormancy of 273–276. 1186 1101 Aspergillus fumigatus conidia. BMC Genomics. 9, 417. Navarro-Velasco, G.Y. et al., 2011. Galleria mellonella as a model host for the trans- 1187 1102 LeibundGut-Landmann, S. et al., 2012. Immunity to fungi. Curr. Opin. Immunol. 24, kingdom pathogen Fusarium oxysporum. Fungal Genet. Biol. 48, 1124–1129. 1188 1103 449–458. Nielsen, K.A. et al., 2000. First touch: an immediate response to surface recognition 1189 1104 Leite, B., Nicholson, R.L., 1992. Mycosporine-alanine: a self-inhibitor of germination in conidia of Blumeria graminis. Physiol. Mol. Plant Pathol. 56, 63–70. 1190 1105 from the conidial mucilage of Collectotrichum graminicola. Exp. Mycol. 16, 76–86. Nishimura, M., Park, G., Xu, J.R., 2003. The G-beta subunit MGB1 is involved in 1191 1106 Lev, S. et al., 1999. A mitogen-activated protein kinase of the corn leaf pathogen regulating multiple steps of infection-related morphogenesis in Magnaporthe 1192 1107 Cochliobolus heterostrophus is involved with conidiation, appressorium grisea. Mol. Microbiol. 50, 231–243. 1193 1108 formation, and pathogenicity: diverse roles for mitogen-activated protein Nucci, M., Anaissie, E., 2007. Fusarium infections in immunocompromised patients. 1194 1109 kinase homologs in foliar pathogens. Proc. Natl. Acad. Sci. USA 96, 13542– Clin. Microbiol. Rev. 20, 695–704. 1195 1110 13547. O’Connell, R.J. et al., 2012. Lifestyle transition in plant pathogenic Colletotrichum 1196 1111 Lewis, L. et al., 2005. Aflatoxin contamination of commercial maize products during fungi deciphered by genome and transcriptome analyses. Nat. Genet., 1060– 1197 1112 an outbreak of acute aflatoxicosis in eastern and central Kenya. Environ. Health. 1065. 1198 1113 Perspect. 113, 1763–1767. Oide, S. et al., 2006. NPS6, encoding a nonribosomal peptide synthetase involved in 1199 1114 Li, G. et al., 2012. Genetic control of infection-related development in Magnaporthe siderophore-mediated iron metabolism, is a conserved virulence determinant 1200 1115 oryzae. Curr. Opin. Microbiol. 15 (6), 678–684. of plant pathogenic ascomycetes. Plant Cell. 18, 2836–2853. 1201 1116 Linder, M.B. et al., 2005. Hydrophobins: the protein-amphiphiles of filamentous Ortoneda, M. et al., 2004. Fusarium oxysporum as a multihost model for the genetic 1202 1117 fungi. FEMS Microbiol. Rev. 29, 877–896. dissection of fungal virulence in plants and mammals. Infect. Immun. 72, 1760– 1203 1118 Liu, H. et al., 2007. Rgs1 regulates multiple G subunits in Magnaporthe 1766. 1204 1119 pathogenesis, asexual growth, and thigmotropism. EMBO J. 26, 690–700. Ospina-Giraldo, M.D. et al., 2003. Loss of function of the Fusarium oxysporum SNF1 1205 1120 Liu, M. et al., 2010. The endothelial cell receptor GRP78 is required for gene reduces virulence on cabbage and Arabidopsis. Curr. Genet. 44, 49–57. 1206 1121 mucormycosis pathogenesis in diabetic mice. J. Clin. Invest. 120, 1914–1924. Osteen, C. et al. Agricultural resources and environmental indicators, 2012 edition. 1207 1122 Lockhart, S.R. et al., 2011. Azole resistance in Aspergillus fumigatus isolates from the United States Department of Agriculture, Economic Research Service. 1208 1123 ARTEMIS global surveillance study is primarily due to TR/L98H mutation in Ouedraogo, R.M. et al., 2002. Attenuation of fungal infection in thermoregulating 1209 1124 cyp51A gene. Antimicrob. Agent. Chemother. 55, 4465–4468. Locusta migratoria is accompanied by changes in hemolymph proteins. J. Invert. 1210 1125 Lockhart, S.R. et al., 2013. Fungal infections associated with contaminated Pathol. 81, 19–24. 1211 1126 methylprednisolone injections – preliminary laboratory report. J. Clin. Ouedraogo, R.M. et al., 2003. Inhibition of fungal growth in thermoregulating 1212 1127 Microbiol. (Epub ahead of print). locusts, Locusta migratoria infected by the fungus Metarhizium anisopliae var 1213 1128 López-Berges, M.S. et al., 2013. The velvet complex governs mycotoxin production acridum. J. Invert. Pathol. 82, 103–109. 1214 1129 and virulence of Fusarium oxysporum on plant and mammalian hosts. Mol. Paolino, K.M. et al., 2012. Invasive fungal infections following combat-related 1215 1130 Microbiol. 87, 49–65. injury. Mil. Med. 177, 681–685. 1216 1131 Lorch, J.M. et al., 2011. Experimental infection of bats with Geomyces destructans Pappas, P.G. et al., 2010. Invasive fungal infections among organ transplant 1217 1132 causes white-nose syndrome. Nature 480, 376–379. recipients: results of the transplant-associated infectious surveillance 1218 1133 Lulloff, S.J. et al., 2004. Fungal susceptibility to zinc deprivation. J. Lab. Clin. Med. network (TRANSET). Clin. Infect. Dis. 50, 1101–1111. 1219 1134 144, 208–214. Pardey, P.G. et al., 2013. Right-sizing stem-rust research. Science 340, 147–148. 1220 1135 Lye, M.S. et al., 1995. An outbreak of acute hepatic encephalopathy due to severe Pareja-Jaime, Y. et al., 2008. Tomatinase from Fusarium oxysporum f. sp. lycopersici is 1221 1136 aflatoxicosis in Malaysia. Am. J. Trop. Med. Hyg. 53, 68–72. required for full virulence on tomato plants. Mol. Plant Microb. Interact. 21, 1222 1137 Mahdavinia, M., Grammer, L.C., 2012. Management of allergic bronchopulmonary 728–736. 1223 1138 aspergillosis: a review and update. Ther. Respir. Dis. 6, 173–187. Park, R. et al., 2011. International surveillance of wheat rust pathogens: progress 1224 1139 Mäkelä, M.R. et al., 2013. Effect of copper, nutrient nitrogen, and wood-supplement and challenges. Euphytica 179, 109–117. 1225 1140 on the production of lignin-modifying enzymes by the white-rot fungus Phlebia Patiño, J.F. et al., 1991. Necrotizing soft tissue lesions after a volcanic cataclysm. 1226 1141 radiata. Fungal. Biol. 117, 62–70. World. J. Surg. 15, 240–247. 1227 1142 Mehl, H.L., Epstein, L., 2007. Fusarium soloni species complex isolates conspecific Pearson, A.K. et al., 2010. Aspergillus niger: an unusual cause of invasive pulmonary 1228 1143 with Fusarium solani f. sp. cucurbitae race 2 from naturally infected human and aspergillosis. J. Med. Mycol. 59, 834–838. 1229 1144 plant tissue and environmental sources are equally virulent on plants, grow at Peñalver, M.C. et al., 1996. Binding of human fibronectin to Aspergillus fumigatus 1230 1145 37 °C and are interfertile. Environ. Microbiol. 9, 2189–2199. conidia. Infect. Immun. 64, 1146–1153. 1231 1146 Mellon, J.E. et al., 2007. Aspergillus flavus hydrolases: their role in pathogenesis and Perfect, S.J. et al., 1999. Colletotrichum: a model genus for studies on pathology and 1232 1147 substrate utilization. Appl. Microbiol. Biotechnol. 77, 497–504. fungal-plant interactions. Fungal Genet. Biol. 27, 186–198. 1233 1148 Mendgen, K., Hahn, M., 2002. Plant infection and the establishment of fungal Peterson, J.D. et al., 2013. Host stress response is important for the pathogenesis of 1234 1149 biotrophy. Trend. Plant Sci. 7, 352–356. the deadly amphibian disease, chytridiomycosis, in Litoria caerulea. PLoS ONE 8, 1235 1150 Menke, J. et al., 2012. Fusarium graminearum Tri12p influences virulence to wheat e62146. 1236 1151 and trichothecene accumulation. Mol. Plant Microb. Interact. 25, 1408–1418. Prados-Rosales, R. et al., 2006. Distinct signaling pathways coordinately contribute 1237 1152 Mercure, E.W. et al., 1994a. Adhesion of Colletotrichum graminicola conidia to corn to virulence of Fusarium oxysporum on mammalian hosts. Microb. Infect. 8, 1238 1153 leaves: a requirement for disease development. Physiol. Mol. Plant Pathol. 45, 2825–2831. 1239 1154 407–420. Pratt, R.G., 2003. An excised-leaf inoculation technique for evaluating host- 1240 1155 Mercure, E.W. et al., 1994b. Adhesion of ungerminated conidia of Colletotrichum pathogen interactions and quantitative resistance of bermudagrass genotypes 1241 1156 graminicola to artificial hydrophobic surfaces. Physiol. Mol. Plant Pathol. 45, to dematiaceous hyphomycetes. Phytopathology 93, 1565–1571. 1242 1157 421–440. Pratt, R.G., 2005. Variation in occurrence of dematiaceous hyphomycetes on forage 1243 1158 Mercure, E.W. et al., 1995. Visualization of materials release from adhered, bermudagrass over years, sampling times, and locations. Phytopathology 95, 1244 1159 ungerminated conidia of Colletotrichum graminicola. Physiol. Mol. Plant Pathol. 1183–1190. 1245 1160 46, 121–135. Proctor, R.H. et al., 1995. Reduced virulence of Gibberella zeae caused by disruption 1246 1161 Michielse, C.B., Rep, M., 2009. Pathogen profile update: Fusarium oxysporum. Mol. of a trichothecene toxin biosynthesis gene. Mol. Plant Microb. Interact. 8, 593– 1247 1162 Plant Pathol. 10, 311–324. 601. 1248 1163 Michielse, C.B. et al., 2012. Degradation of aromatic compounds through the b- Revankar, S., Sutton, D.A., 2010. Melanized fungi in human disease. Clin. Microbiol. 1249 1164 ketoadipate pathway is required for pathogenicity of the tomato wilt pathogen Rev. 23, 884–928. 1250 1165 Fusarium oxysporum f. sp. Lycopersici. Mol. Plant Pathol. 13, 1089–1100. Ribes, J.A., Vanover-Sams, C.L., Baker, D.J., 2000. Zygomycetes in human disease. Clin 1251 1166 Minnis, A.W., Lindner, D.L., 2013. Phylogenetic evaluation of Geomyces and allies Microbiol. Rev. 13, 236–301. 1252 1167 reveals no close relatives of Pseudogymnoascus destructans, comb. nov., in bat Robert, V.A., Casadevall, A., 2009. Vertebrate endothermy restricts most fungi as 1253 1168 Q7 hibernacula of eastern North America. Fungal. Biol. In press. potential pathogens. J. Infect. Dis. 200, 1623–1626. 1254 1169 Mitchell, T.K., Dean, R.A., 1995. The cAMP-dependent protein kinase catalytic Rossman, A.Y., 2009. The impact of invasive fungi on agricultural ecosystems in the 1255 1170 subunit is required for appressorium formation and pathogenesis by the rice United States. Biol. Invasions. 11, 97–107. 1256 1171 blast pathogen Magnaporthe grisea. Plant Cell. 7, 1869–1878. Ryder, L.S. et al., 2013. NAPD oxidases regulate septin-mediated cytoskeletal 1257 1172 Mori, T. et al., 1998. Systemic aspergillosis caused by an aflatoxin-producing strain remodeling during plant infection by the rice blast fungus. Proc. Natl. Acad. Sci. 1258 1173 of Aspergillus flavus. Med. Mycol. 36, 107–112. USA 110, 3179–3184. 1259 1174 Mortensen, K.L. et al., 2010. Environmental study of azole-resistant Aspergillus Saha, A. et al., 2008. Influence of culture media and environmental factors on 1260 1175 fumigatus and other Aspergilli in Austria, Denmark, and Spain. Antimicrob. mycelial growth and sporulation of Lasiodiplodia theobromae (Pat.) Griffon and 1261 1176 Agent Chemother. 54, 4545–4549. Maubl. J. Environ. Biol. 29, 407–410. 1262 1177 Mukherjee, P.K. et al., 2012. Characterization of Fusarium keratitis outbreak isolates: Schrettl, M. et al., 2007. Distinct roles for intra- and extracellular siderophores 1263 1178 contribution of biofilms to antimicrobial resistance and pathogenesis. Invest. during Aspergillus fumigatus infection. PLoS. Pathog. 28, 1195–1207. 1264 1179 Ophthalmol. Vis. Sci. 53, 4450–4457. Schrettl, M. et al., 2004. Siderophore biosynthesis but not reductive iron 1265 1180 Mullins, J., Seaton, A., 1978. Fungal spores in lung and sputum. Clin. Exp. Allergy 8, assimilation is essential for Aspergillus fumigatus virulence. J. Exp. Med. 200, 1266 1181 525–533. 1213–1219. 1267 1182 Münch, S. et al., 2008. The hemibiotrophic lifestyle of Colletotrichum species. J. Plant Schrettl, M. et al., 2010. HapX-mediation adaptation to iron starvation is crucial for 1268 1183 Physiol. 165, 41–51. virulence of Aspergillus fumigatus. PLoS. Pathog. 6, e1001124. 1269

12 G.M. Gauthier, N.P. Keller / Fungal Genetics and Biology xxx (2013) xxx–xxx

1270 Seong, K.Y. et al., 2008. Conidial germination in the filamentous fungus Fusarium Warnecke, L. et al., 2013. Pathophysiology of white-nose syndrome in bats: a 1335 1271 graminearum. Fungal Genet. Biol. 45, 389–399. mechanistic model linking wing damage to mortality. Biol. Lett. 9, 20130177. 1336 1272 Sexton, A.C., Howlett, B.J., 2006. Parallels in fungal pathogenesis on plant and Warpeha, K.M. et al., 2013. Susceptibility of intact germinating Arabidopsis thaliana 1337 1273 animal hosts. Eukaryot. Cell. 5, 1941–1949. to human fungal pathogens Cryptococus neoformans and C. gatti. Appl. Environ. 1338 1274 Smith, R.M. et al., 2012. Fungal Infections associated with contaminated Microbiol. 79, 2979–2988. 1339 1275 methylprednisolone injections – preliminary report. N. Engl. J. Med. (Epub Wasylnka, J.A., Moore, M.M., 2000. Adhesion of Aspergillus species to extracellular 1340 1276 ahead of print). matrix proteins: evidence for involvement of negatively charged carbohydrates 1341 1277 Snelders, E. et al., 2008. Emergence of azole resistance in Aspergillus fumigatus and on the conidial surface. Infect. Immun. 68, 3377–3384. 1342 1278 spread of a single resistance mechanism. PLoS Med. 5, e219. Wasylnka, J.A. et al., 2001. Differences in sialic acid density in pathogenic and non- 1343 1279 Snelders, E. et al., 2009. Possible environmental origin of resistance of Aspergillus pathogenic Aspergillus species. Microbiology 147, 869–877. 1344 1280 fumigatus to medical triazoles. Appl. Environ. Microbiol. 75, 4053–4057. Waterman, S.R. et al., 2013. Role of CTR4 in the virulence of Cryptococcus 1345 1281 Snelders, E. et al., 2011. The structure-function relationship of the Aspergillus neoformans. MBio 3, e00285-12. 1346 1282 fumigatus cyp51A L98H conversion by site-directed mutagenesis: the Watson, D.W. et al., 1993. Behavioral fever response of Musca domestica (Diptera: 1347 1283 mechanism of L98H azole resistance. Fungal Genet. Biol. 2011, 1062–1070. Muscidae) to infection by Entomophthora muscae (Zygomycetes: 1348 1284 Snelders, E. et al., 2012. Triazole fungicides can induce cross-resistance to medical Entomophthorales). J. Invert. Pathol. 61, 10–16. 1349 1285 triazoles in Aspergillus fumigatus. PLoS ONE 7, e31801. Wiemann, P. et al., 2010. FfVel1 and FfLae1, components of a velvet-like complex in 1350 1286 Srinoulprasert, Y. et al., 2009. Engagement of Penicillium marneffei conidia with Fusarium fujikuroi, affect differentiation, secondary metabolism and virulence. 1351 1287 multiple pattern recognition receptors on human monocytes. Microbiol. Mol. Microbiol. 77, 972–994. 1352 1288 Immunol. 53, 162–172. Wild, C.P., Gong, Y.Y., 2010. Mycotoxins and human disease: a largely ignored global 1353 1289 Srivastava, K.C. et al., 2005. Effect of conidial concentration of Alternaria alternata on health issue. Carcinogenesis 31, 71–82. 1354 1290 germination and intensity of blight of tomato. Ann. Plant Protec. Sci. 13, 510– Wilson, R.A., Talbot, N.J., 2009. Under pressure: investigating the biology of plant 1355 1291 512. infection by Magnaporthe oryzae. Nat. Rev. Microbiol. 7, 185–195. 1356 1292 Stergiopoulos, I. et al., 2013. Phytotoxic secondary metabolites and peptides Wilson, D. et al., 2012. Zinc exploitation by pathogenic fungi. PLoS Pathog. 8, 1357 1293 produced by plant pathogenic Dothideomycete fungi. FEMS Microbiol. Rev. 37, e1003034. 1358 1294 67–93. Woloshuk, C.P., Shim, W.B., 2013. Aflatoxins, fumonisins, and trichothecenes: a 1359 1295 Subramaniam, R., Rampitsch, C., 2013. Towards systems biology of mycotoxin convergence of knowledge. FEMS Microbiol. Rev. 37, 94–109. 1360 1296 regulation. Toxins (Basel) 5, 675–685. Woodhams, D.C. et al., 2003. Emerging disease of amphibians cured by elevated 1361 1297 Sugui, J.A. et al., 1998. Partial characterization of the extracellular matrix released body temperature. Dis. Aqat. Org. 55, 65–67. 1362 1298 onto hydrophobic surfaces by conidia and conidial germlings of Colletotrichum Woolhouse, M., Gaunt, E., 2007. Ecologic origins of novel human pathogens. Crit. 1363 1299 graminicola. Physiol. Mol. Plant Pathol. 52, 411–425. Rev. Microbiol. 33, 231–242. 1364 1300 Torres-Rodriguez, J.M. et al., 2005. Successful thermotherapy for a subcutaneous Wouters, A.T. et al., 2013. An outbreak of aflatoxin poisoning in dogs associated 1365 1301 infection due to Alternaria alternata in a renal transplant recipient. Arch. with aflatoxin B1-contaminated maize products. J. Vet. Diagn. Invest. 25, 282– 1366 1302 Dermatol. 141, 1171–1173. 287. 1367 1303 Tronchin, G. et al., 1997. Expression and identification of a laminin-binding protein Wu, D. et al., 2012. ChLae1 and ChVel1 regulate T-toxin production, virulence, 1368 1304 in Aspergillus fumigatus conidia. Infect. Immun. 65, 9–15. oxidative stress response, and development of the maize pathogen Cochliobolus 1369 1305 Tucker, S.L., Talbot, N.J., 2001. Surface attachment and pre-penetration stage heterostrophus. PLoS Pathog. 8, e1002542. 1370 1306 development by plant pathogenic fungi. Annu. Rev. Phytopathol. 39, 385–417. Xu, J.R., Hamer, J.E., 1996. MAP kinase and cAMP signaling regulate infection 1371 1307 Upadhyay, S.K. et al., 2009. Identification and characterization of a laminin-binding structure formation and pathogenic growth in the rice blast fungus 1372 1308 protein of Aspergillus fumigatus: extracellular thaumatin domain protein Magnaporthe grisea. Genes. Dev. 10, 2696–2706. 1373 1309 (AfCalAp). J. Med. Microbiol. 58, 714–722. Xu, J.R. et al., 1998. Inactivation of the mitogen-activated protein kinase Mps1 from 1374 1310 USDA ARS website. nt.ars-grin.gov/fungaldatabases. (accessed June 2013). the rice blast fungus prevents penetration of host cells but allows activation of 1375 1311 van der Linden, J.W.M. et al., 2011. Clinical implications of azole resistance in plant defense reponses. Proc. Natl. Acad. Sci. USA 95, 12713–12718. 1376 1312 Aspergillus fumigatus, the Netherlands, 2007–2009. Emerg. Infect. Dis. 17, Xu, X.Y. et al., 2012. E-cadherin mediates adhesion and endocytosis of Aspergillus 1377 1313 1846–1854. fumigatus blastospores in human epithelial cells. Chin. Med. J. 125, 617–621. 1378 1314 van der Linden, J.W.M. et al., 2013. Aspergillosis due to voriconazole highly- Yang, S.M., 1973. Isolation and effect of temperature on spore germination, radial 1379 1315 resistant Aspergillus fumigatus and recovery of genetically related resistant growth, and pathogenicity of Curvularia senegalensis. Phytopathology 63, 1541– 1380 1316 isolates from domiciles. Clin. Infect. Dis. 57, 513–520. 1542. 1381 1317 van Leeuwen, M.R. et al., 2013. Germination of conidia of Aspergillus niger is Yang, Z. et al., 2000. Enhanced binding of Aspergillus fumigatus spores to A549 1382 1318 accompanied by major changes in RNA profiles. Stud. Mycol. 74, 59–70. epithelial cells and extracellular matrix proteins by a component from the spore 1383 1319 Verant, M.L. et al., 2012. Temperature-dependent growth of Geomyces destructans, surface and inhibition by rat lung lavage fluid. Thorax 55, 579–584. 1384 1320 the fungus that causes bat white-nose syndrome. PLoS ONE 7, e46280. Yang, Q., Chen, Y., Ma, Z., 2013. Involvement of BcVeA and BcVelB in regulating 1385 1321 Verweij, P.E. et al., 2009. Azole resistance in Aspergillus fumigatus: a side-effect of conidiation, pigmentation and virulence in Botrytis cinerea. Fungal Genet. Biol. 1386 1322 environmental fungicide use? Lancet Infect. Dis. 9, 789–795. 50, 63–71. 1387 1323 Voyles, J. et al., 2009. Pathogenesis of chytridiomycosis, a cause of catastrophic Yin, W.B. et al., 2013. A nonribosomal peptide synthetase-derived iron (III) complex 1388 1324 amphibian declines. Science 326, 582–585. from the pathogenic fungus Aspergillus fumigatus. J. Am. Chem. Soc. 135, 2064– 1389 1325 Vurro, M. et al., 2010. Emerging infectious diseases of crop plants in developing 2067. 1390 1326 countries: impact on agriculture and socioeconomic consequences. Food Sec. 2, Zhang, N. et al., 2006. Members of the Fusarium solani species complex that cause 1391 1327 113–132. infection in both humans and plants are common in the environment. J. Clin. 1392 1328 Wang, Y.Z. et al., 2005. The molecular biology of appressorium turgor generation by Microbiol. 44, 2186–2190. 1393 1329 the rice blast fungus Magnaporthe grisea. Biochem. Soc. Trans. 33, 384–388. Zhang, S. et al., 2011. Two hydrophobins are involved in fungal spore coat rodlet 1394 1330 Warkentien, T. et al., 2012. Invasive mold infections following combat-related layer assembly and each play a distinctive role in surface interactions, 1395 1331 injuries. Clin. Infect. Dis. 55, 1441–1449. development and pathogenesis in the entomopathogenic fungus, Beauveria 1396 1332 Warnecke, L. et al., 2012. Inoculation of bats with European Geomyces destructans bassiana. Mol. Microbiol. 80, 811–826. 1397 1333 supports the novel pathogen hypothesis for the origin of white-nose syndrome. 1398 1334 Proc. Natl. Acad. Sci. USA 109, 6999–7003.