Coniochaeta (Lecythophora), Collophora Gen. Nov. and Phaeomoniella Species Associated with Wood Necroses of Prunus Trees
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Persoonia 24, 2010: 60–80 www.persoonia.org RESEARCH ARTICLE doi:10.3767/003158510X500705 Coniochaeta (Lecythophora), Collophora gen. nov. and Phaeomoniella species associated with wood necroses of Prunus trees U. Damm1,2, P.H. Fourie1,3, P.W. Crous1,2 Key words Abstract Species of the genus Coniochaeta (anamorph: Lecythophora) are known as pathogens of woody hosts, but can also cause opportunistic human infections. Several fungi with conidial stages resembling Lecythophora Collophora were isolated from necrotic wood samples of Prunus trees in South Africa. In order to reveal their phylogenetic Coniochaeta relationships, these fungi were studied on a morphological and molecular (5.8S nrDNA, ITS-1, ITS-2, GAPDH, EF-1α EF-1 , 28S nrDNA, 18S nrDNA) basis. Some of the isolates were identified as Coniochaeta (Sordariomycetes), GAPDH α including C. velutina and two new species, C. africana and C. prunicola. The majority of the isolates, however, ITS formed pycnidial or pseudopycnidial synanamorphs and were not closely related to Coniochaeta. According to their Lecythophora 28S nrDNA phylogeny, they formed two distinct groups, one of which was closely related to Helotiales (Leotio LSU mycetes). The new genus Collophora is proposed, comprising five species that frequently occur in necrotic peach pathogenicity and nectarine wood, namely Co. africana, Co. capensis, Co. paarla, Co. pallida and Co. rubra. The second group Phaeomoniella was closely related to Phaeomoniella chlamydospora (Eurotiomycetes), occurring mainly in plum wood. Besides Prunus P. zymoides occurring on Prunus salicina, four new species are described, namely P. dura, P. effusa, P. prunicola SSU and P. tardicola. In a preliminary inoculation study, pathogenicity was confirmed for some of the new species on systematics apricot, peach or plum wood. Article info Received: 15 January 2010; Accepted: 8 February 2010; Published: 1 April 2010. INTRODUCTION Cain 1971) within the Coniochaetales (Huhndorf et al. 2004, García et al. 2006). Coniochaeta is homothallic, and usually Gams & McGinnis (1983) reintroduced the genus Lecythophora produces perithecia in culture (Raju & Perkins 2000). How- (Melin & Nannfeldt 1934), confining it to anamorphs of Conio ever, in some species/strains these perithecia remain infertile chaeta, and excluding it from Phialophora sensu Schol-Schwarz (Weber 2002). (1970), who placed these fungi in the Phialophora hoffmannii Species of Coniochaeta and their Lecythophora anamorphs or Phialophora lignicola groups. Lecythophora is characterised occur on dung of various animals (mainly mammals), in wood- by its hyaline hyphae and its mostly intercalary phialides with pulp, on wood or bark of different trees, in water (even with very short lateral necks, periclinal wall thickening and flaring extremely low pH and high concentrations of heavy metals), collarettes (Gams 2000). Weber studied the morphology and in soil, leaves, and leaf litter, and rarely in non-woody host LSU phylogeny of a number of Lecythophora species, several plants like Gramineae (Melin & Nannfeldt 1934, Eriksson 1992, of which were linked to species of the ascomycetous genus López-Archilla et al. 2004, Asgari et al. 2007). Coniochaeta/ Coniochaeta (Weber 2002, Weber et al. 2002). Currently, 17 Lecythophora species have been isolated from asymptomatic, Coniochaeta species and one Barrina species are known to dormant buds and young plants of Vitis vinifera (Dugan et al. form Lecythophora anamorphs, including anamorphs that can 2002, Casieri et al. 2009). Coniochaeta ligniaria was isolated be considered as Lecythophora, but were described as Phia from decaying bark of Prunus avium in the Netherlands (CBS lophora or Hormonema (Moreau & Moreau 1949, Cain 1961, 178.75). Popushoi (1971) reported several species on fruit trees Minoura et al. 1977, Udagawa & Furuya 1979, Hawksworth & in Moldavia: C. ambigua on dry twigs of apricot and cherry, Yip 1981, Mahoney & La Favre 1981, Udagawa & Sugiyama C. calva on twigs of quince, cherry and plum, C. ligniaria on 1982, Yokoyama & Ito 1988, Kamiya et al. 1995, Ramaley 1997, dry twigs and wood of pear and plum and C. velutina on wood Romero et al. 1999, Weber 2002, Asgari & Zare 2006). Other of apple and pear trees. Coniochaeta species form different anamorphs, or have not yet been linked to any anamorph (García et al. 2006, Asgari et Some species such as Lecythophora hoffmannii (teleomorph: al. 2007). The most recent key comprises 54 well-documented Coniochaeta ligniaria) and L. mutabilis are also known as hu- Coniochaeta species (Asgari et al. 2007). However, only 21 man pathogens involved in keratitis, subcutanous abscesses, Coniochaeta species were included in the latest published DNA peritonitis, endocarditis and septic shock (de Hoog et al. 2000, phylogeny of the genus (García et al. 2006). Coniochaeta and Drees et al. 2007, Taniguchi et al. 2009). They have also been Barrina polyspora belong to the Coniochaetaceae (Malloch & isolated from food, e.g., butter (Samson et al. 2004). On the other hand, some Coniochaeta species have been found to 1 Department of Plant Pathology, University of Stellenbosch, P. Bag X1, exhibit useful biochemical properties. For example, a strain of Stellenbosch 7602, South Africa. Coniochaeta ellipsoidea forms the newly discovered antibiotic 2 CBS-KNAW Fungal Biodiversity Centre, Uppsalalaan 8, 3584 CT Utrecht, coniosetin, which has a pronounced antibacterial and antifungal The Netherlands; corresponding author e-mail: [email protected]. 3 Citrus Research International, P.O. Box 2201, Stellenbosch 7602, South action, inhibiting even drug-resistant strains of Staphylococcus Africa. aureus (Segeth et al. 2003). Coniochaeta ligniaria is effective © 2010 Nationaal Herbarium Nederland & Centraalbureau voor Schimmelcultures You are free to share - to copy, distribute and transmit the work, under the following conditions: Attribution: You must attribute the work in the manner specified by the author or licensor (but not in any way that suggests that they endorse you or your use of the work). Non-commercial: You may not use this work for commercial purposes. No derivative works: You may not alter, transform, or build upon this work. For any reuse or distribution, you must make clear to others the license terms of this work, which can be found at http://creativecommons.org/licenses/by-nc-nd/3.0/legalcode. Any of the above conditions can be waived if you get permission from the copyright holder. Nothing in this license impairs or restricts the author’s moral rights. U. Damm et al.: Coniochaeta, Collophora and Phaeomoniella 61 in biological detoxification of lignocellulosic biomass and can of these different Lecythophora-like fungi, as well as to describe potentially be used to convert it to fuels and chemicals (López the new species and test their pathogenicity on Prunus. et al. 2004). Colonisation of torrefied grass fibres with the same fungus resulted in reduced phytotoxicity and increased plant Materials AND METHODS growth (Trifonova et al. 2009). While intercalary phialides with short lateral necks are charac- Sampling and fungal isolation teristic for the genus Lecythophora, several other genera are Fungi were isolated from branches of trees with dieback or known that also commonly form intercalary hyphal cells with necrotic symptoms. Samples were taken in stone fruit (Prunus conidiogenous protrusions that are not separated from the spp.) orchards in the Western Cape and the Limpopo Provinces hyphal cell by a septum, or are even reduced to short necks of South Africa according to the method described in Damm or openings with collarettes. Examples include Phialemonium et al. (2007). Single-conidial isolates were obtained from the (Gams & McGinnis 1983), the Calosphaeriophora anamorph strains for further study. Reference strains are maintained in of Calosphaeria africana (Damm et al. 2008a), two newly de- the culture collection of the Department of Plant Pathology, scribed Phaeomoniella species (Lee et al. 2006), Phialophora University of Stellenbosch (STE-U) in Stellenbosch, South sessilis and Phialophora reptans (de Hoog et al. 1999) and Africa, and the CBS-KNAW Fungal Biodiversity Centre (CBS) Neotyphodium (Morgan-Jones & Gams 1982, Glenn et al. Utrecht, The Netherlands. Isolates used for morphological and 1996). Also, Cladorrhinum almost exclusively produces inter- sequence analyses and in the preliminary pathogenicity test calary phialides with widely flaring collarettes (von Arx & Gams are presented in Table 1. 1967). Weber (2002) described two species, ‘Lecythophora’ spp. 1 and 2, that are similar to Lecythophora, but not closely Morphological analysis related to it (Weber et al. 2002). In the following overview, we To enhance sporulation, double-autoclaved pine needles or will refer to genera with phialidic conidiogenesis that mainly double autoclaved grapevine wood pieces were placed onto the form reduced intercalary phialides. These variant phialides surface of synthetic nutrient-poor agar medium (SNA; Nirenberg range in form from adelophialides, which are hyphal cells with 1976), and incubated at 25 °C in the dark for 2 wk (anamorphs) or longer or shorter protrusions or necks, often opening with a 2–3 mo (teleomorphs). Measurements, photographs of charac- collarette and not delimited by a basal septum, to aphanophi- teristic structures and vertical sections through ascomata and alides, which are verticillately arranged, reduced, flask-shaped conidiomata were made according to Damm et al. (2007). Micro- phialides with