DOCSLIB.ORG

Isolation and Characterisation of Novel Nematophagous Fungi from Eggs of the Cereal Cyst Nematode Heterodera Filipjevi and Ident

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Isolation and Characterisation of Novel Nematophagous Fungi from Eggs of the Cereal Cyst Nematode Heterodera Filipjevi and Ident Isolation and characterisation of novel nematophagous fungi from eggs of the cereal cyst nematode Heterodera filipjevi and identifying their secondary metabolites with nematicidal activity Dissertation Zur Erlangung des Akademischen Grades eines Doktors der Agrarwissenschaften (Dr. agr.) Eingereicht am Fachbereich Ökologische Agrarwissenschaften der Universität Kassel Von Samad Ashrafi February 2018 Samad Ashrafi (2018) Isolation and characterisation of novel nematophagous fungi from eggs of the cereal cyst nematode Heterodera filipjevi and identifying their secondary metabolites with nematicidal activity A thesis in Biological control: University of Kassel Defence date: 17.04.2018 Place: Witzenhausen, Germany Supervisors: Prof. Dr. Maria R. Finckh (University of Kassel) Dr. Wolfgang Maier (Julius Kühn-Institut — Federal Research Center for Cultivated Plants) For Saleh Table of Contents List of Tables ........................................................................................................................................... vii List of Figures ......................................................................................................................................... viii Chapter 1. General Introduction ....................................................................................................... 1 1.1 Cereal cyst nematodes ............................................................................................................ 1 1.2 Biocontrol of nematodes ......................................................................................................... 3 1.3 Nematophagous fungi ............................................................................................................. 4 1.3.1 Nematode-trapping fungi ................................................................................................ 5 1.3.2 Endoparasitic fungi .......................................................................................................... 6 1.3.3 Egg-parasitic fungi ........................................................................................................... 7 1.4 Suppression of PPNs with nematophagous fungi ................................................................... 8 1.5 Nematophagous fungi, a source of nematicidal metabolites ............................................... 11 1.6 Introduction to the project.................................................................................................... 12 1.7 Research rationale and objectives of the project ................................................................. 15 1.8 Refernces ............................................................................................................................... 17 Chapter 2. Ijuhya vitellina sp. nov., a novel source for chaetoglobosin A, is a destructive parasite of the cereal cyst nematode Heterodera filipjevi .......................................................... 22 2.1 Introduction ........................................................................................................................... 23 2.2 Material and methods ........................................................................................................... 24 2.2.1 Nematode collection and materials examined ............................................................. 24 2.2.2 Ethics statement ............................................................................................................ 25 2.2.3 Fungal isolation from field collected samples ............................................................... 25 2.2.4 Pure culture based studies ............................................................................................ 26 2.2.5 Pathogenicity test and Koch’s postulate ....................................................................... 26 2.2.6 Light and scanning electron microscopy ....................................................................... 27 2.2.7 DNA extraction .............................................................................................................. 27 2.2.8 PCR amplification and sequencing ................................................................................ 28 2.2.9 Alignment and phylogenetic reconstruction ................................................................. 28 2.2.10 Nomenclature ................................................................................................................ 37 2.2.11 Metabolite profiling....................................................................................................... 37 2.3 Results ................................................................................................................................... 38 2.3.1 Fungal isolation ............................................................................................................. 38 2.3.2 Molecular phylogenetic studies .................................................................................... 39 2.3.3 Taxonomy ...................................................................................................................... 42 2.3.4 In vitro parasitism on nematode eggs and Koch’s postulates ....................................... 45 iv 2.3.5 Metabolite profiling....................................................................................................... 48 2.4 Discussion .............................................................................................................................. 49 2.4.1 Phylogenetic analyses and systematic implications ...................................................... 49 2.4.2 Parasitism on nematode cysts and eggs ....................................................................... 50 2.4.3 Metabolite profiling....................................................................................................... 51 2.5 Appendix ................................................................................................................................ 53 2.6 References ............................................................................................................................. 54 2.7 Supporting information ......................................................................................................... 60 Chapter 3. Monocillium gamsii sp. nov. and Monocillium bulbillosum: two nematode-associated fungi parasitising the eggs of Heterodera filipjevi ......................................................... 67 3.1 Introduction ........................................................................................................................... 68 3.2 Material and methods ........................................................................................................... 69 3.2.1 Sample collection and materials examined ................................................................... 69 3.2.2 Cultural studies .............................................................................................................. 70 3.2.3 Pathogenicity tests against H. filipjevi ........................................................................... 70 3.2.4 Microscopy .................................................................................................................... 71 3.2.5 Molecular phylogenetic studies .................................................................................... 71 3.3 Results ................................................................................................................................... 74 3.3.1 Sample collection and fungal isolation .......................................................................... 74 3.3.2 Sequence comparison and phylogenetic inference ...................................................... 75 3.3.3 Taxonomy ...................................................................................................................... 76 3.3.4 Development of M. gamsii in nematode eggs in vitro .................................................. 79 3.3.5 Parasitism of M. bulbillosum towards H. filipjevi .......................................................... 81 3.4 Discussion .............................................................................................................................. 81 3.5 References ............................................................................................................................. 84 Chapter 4. Inhabiting plant roots, nematodes and truffles — Polyphilus nom. prov., a new helotialean genus with two globally distributed species .............................................. 87 4.1 Introduction ........................................................................................................................... 88 4.2 Material and methods ........................................................................................................... 90 4.2.1 Origin of isolates ............................................................................................................ 90 4.2.2 Fungal isolation from nematode eggs ........................................................................... 90 4.2.3 Sporulation and morphology of isolates ....................................................................... 90 4.2.4 DNA extraction and amplification ................................................................................. 92 4.2.5 Phylogenetic analyses ..................................................................................................
Load more

Recommended publications
  • Diversity of Endophytic Fungi from Different Verticillium-Wilt-Resistant
    J. Microbiol. Biotechnol. (2014), 24(9), 1149–1161 http://dx.doi.org/10.4014/jmb.1402.02035 Research Article Review jmb Diversity of Endophytic Fungi from Different Verticillium-Wilt-Resistant Gossypium hirsutum and Evaluation of Antifungal Activity Against Verticillium dahliae In Vitro Zhi-Fang Li†, Ling-Fei Wang†, Zi-Li Feng, Li-Hong Zhao, Yong-Qiang Shi, and He-Qin Zhu* State Key Laboratory of Cotton Biology, Institute of Cotton Research of Chinese Academy of Agricultural Sciences, Anyang, Henan 455000, P. R. China Received: February 18, 2014 Revised: May 16, 2014 Cotton plants were sampled and ranked according to their resistance to Verticillium wilt. In Accepted: May 16, 2014 total, 642 endophytic fungi isolates representing 27 genera were recovered from Gossypium hirsutum root, stem, and leaf tissues, but were not uniformly distributed. More endophytic fungi appeared in the leaf (391) compared with the root (140) and stem (111) sections. First published online However, no significant difference in the abundance of isolated endophytes was found among May 19, 2014 resistant cotton varieties. Alternaria exhibited the highest colonization frequency (7.9%), *Corresponding author followed by Acremonium (6.6%) and Penicillium (4.8%). Unlike tolerant varieties, resistant and Phone: +86-372-2562280; susceptible ones had similar endophytic fungal population compositions. In three Fax: +86-372-2562280; Verticillium-wilt-resistant cotton varieties, fungal endophytes from the genus Alternaria were E-mail: [email protected] most frequently isolated, followed by Gibberella and Penicillium. The maximum concentration † These authors contributed of dominant endophytic fungi was observed in leaf tissues (0.1797). The evenness of stem equally to this work.
    [Show full text]
  • Leptographium Wageneri
    Leptographium wageneri back stain root disease Dutch elm disease and Scolytus multistriatus DED caused the death of millions of elms in Europe and North America from around 1920 through the present Dutch Elm Disease epidemics in North America Originally thought one species of Ophiostoma, O. ulmi with 3 different races Now two species are recognized, O. ulmi and O. novo-ulmi, and two subspecies of O. novo-ulmi Two nearly simultaneous introductions in North America and Europe 1920s O. ulmi introduced from Europe, spread throughout NA, but caused little damage to native elm trees either in NA or Europe 1950s, simultaneous introductions of O. novo-ulmi, Great Lakes area of US and Moldova-Ukraine area of Europe. North American and Europe subspecies are considered distinct. 1960 NA race introduced to Europe via Canada. By 1970s much damage to US/Canada elms killed throughout eastern and central USA O. novo-ulmi has gradually replaced O. ulmi in both North America and Europe more fit species replacing a less fit species O. novo-ulmi able to capture greater proportion of resource O. novo-ulmi probably more adapted to cooler climate than O. ulmi During replacement, O. ulmi and O. novo-ulmi occur in close proximity and can hybridize. Hybrids are not competitive, but may allow gene flow from O. ulmi to O. novo-ulmi by introgression: Backcrossing of hybrids of two plant populations to introduce new genes into a wild population Vegetative compatibility genes heterogenic incompatibility multiple loci prevents spread of cytoplasmic viruses O. novo-ulmi arrived as a single vc type, but rapidly acquired both new vc loci AND virus, probably from hybridizing with O.
    [Show full text]
  • Distribution of Methionine Sulfoxide Reductases in Fungi and Conservation of the Free- 2 Methionine-R-Sulfoxide Reductase in Multicellular Eukaryotes
    bioRxiv preprint doi: https://doi.org/10.1101/2021.02.26.433065; this version posted February 27, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. 1 Distribution of methionine sulfoxide reductases in fungi and conservation of the free- 2 methionine-R-sulfoxide reductase in multicellular eukaryotes 3 4 Hayat Hage1, Marie-Noëlle Rosso1, Lionel Tarrago1,* 5 6 From: 1Biodiversité et Biotechnologie Fongiques, UMR1163, INRAE, Aix Marseille Université, 7 Marseille, France. 8 *Correspondence: Lionel Tarrago ([email protected]) 9 10 Running title: Methionine sulfoxide reductases in fungi 11 12 Keywords: fungi, genome, horizontal gene transfer, methionine sulfoxide, methionine sulfoxide 13 reductase, protein oxidation, thiol oxidoreductase. 14 15 Highlights: 16 • Free and protein-bound methionine can be oxidized into methionine sulfoxide (MetO). 17 • Methionine sulfoxide reductases (Msr) reduce MetO in most organisms. 18 • Sequence characterization and phylogenomics revealed strong conservation of Msr in fungi. 19 • fRMsr is widely conserved in unicellular and multicellular fungi. 20 • Some msr genes were acquired from bacteria via horizontal gene transfers. 21 1 bioRxiv preprint doi: https://doi.org/10.1101/2021.02.26.433065; this version posted February 27, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license.
    [Show full text]
  • Illuminating Type Collections of Nectriaceous Fungi in Saccardo's
    Persoonia 45, 2020: 221–249 ISSN (Online) 1878-9080 www.ingentaconnect.com/content/nhn/pimj RESEARCH ARTICLE https://doi.org/10.3767/persoonia.2020.45.09 Illuminating type collections of nectriaceous fungi in Saccardo’s fungarium N. Forin1, A. Vizzini 2,3,*, S. Nigris1,4, E. Ercole2, S. Voyron2,3, M. Girlanda2,3, B. Baldan1,4,* Key words Abstract Specimens of Nectria spp. and Nectriella rufofusca were obtained from the fungarium of Pier Andrea Saccardo, and investigated via a morphological and molecular approach based on MiSeq technology. ITS1 and ancient DNA ITS2 sequences were successfully obtained from 24 specimens identified as ‘Nectria’ sensu Saccardo (including Ascomycota 20 types) and from the type specimen of Nectriella rufofusca. For Nectria ambigua, N. radians and N. tjibodensis Hypocreales only the ITS1 sequence was recovered. On the basis of morphological and molecular analyses new nomenclatural Illumina combinations for Nectria albofimbriata, N. ambigua, N. ambigua var. pallens, N. granuligera, N. peziza subsp. ribosomal sequences reyesiana, N. radians, N. squamuligera, N. tjibodensis and new synonymies for N. congesta, N. flageoletiana, Sordariomycetes N. phyllostachydis, N. sordescens and N. tjibodensis var. crebrior are proposed. Furthermore, the current classifi- cation is confirmed for Nectria coronata, N. cyanostoma, N. dolichospora, N. illudens, N. leucotricha, N. mantuana, N. raripila and Nectriella rufofusca. This is the first time that these more than 100-yr-old specimens are subjected to molecular analysis, thereby providing important new DNA sequence data authentic for these names. Article info Received: 25 June 2020; Accepted: 21 September 2020; Published: 23 November 2020. INTRODUCTION to orange or brown perithecia which do not change colour in 3 % potassium hydroxide (KOH) or 100 % lactic acid (LA) Nectria, typified with N.
    [Show full text]
  • Worms, Nematoda
    University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Faculty Publications from the Harold W. Manter Laboratory of Parasitology Parasitology, Harold W. Manter Laboratory of 2001 Worms, Nematoda Scott Lyell Gardner University of Nebraska - Lincoln, [email protected] Follow this and additional works at: https://digitalcommons.unl.edu/parasitologyfacpubs Part of the Parasitology Commons Gardner, Scott Lyell, "Worms, Nematoda" (2001). Faculty Publications from the Harold W. Manter Laboratory of Parasitology. 78. https://digitalcommons.unl.edu/parasitologyfacpubs/78 This Article is brought to you for free and open access by the Parasitology, Harold W. Manter Laboratory of at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Faculty Publications from the Harold W. Manter Laboratory of Parasitology by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Published in Encyclopedia of Biodiversity, Volume 5 (2001): 843-862. Copyright 2001, Academic Press. Used by permission. Worms, Nematoda Scott L. Gardner University of Nebraska, Lincoln I. What Is a Nematode? Diversity in Morphology pods (see epidermis), and various other inverte- II. The Ubiquitous Nature of Nematodes brates. III. Diversity of Habitats and Distribution stichosome A longitudinal series of cells (sticho- IV. How Do Nematodes Affect the Biosphere? cytes) that form the anterior esophageal glands Tri- V. How Many Species of Nemata? churis. VI. Molecular Diversity in the Nemata VII. Relationships to Other Animal Groups stoma The buccal cavity, just posterior to the oval VIII. Future Knowledge of Nematodes opening or mouth; usually includes the anterior end of the esophagus (pharynx). GLOSSARY pseudocoelom A body cavity not lined with a me- anhydrobiosis A state of dormancy in various in- sodermal epithelium.
    [Show full text]
  • Evolution of Nematode-Trapping Cells of Predatory Fungi of the Orbiliaceae Based on Evidence from Rrna-Encoding DNA and Multiprotein Sequences
    Evolution of nematode-trapping cells of predatory fungi of the Orbiliaceae based on evidence from rRNA-encoding DNA and multiprotein sequences Ying Yang†‡, Ence Yang†‡, Zhiqiang An§, and Xingzhong Liu†¶ †Key Laboratory of Systematic Mycology and Lichenology, Institute of Microbiology, Chinese Academy of Sciences 3A Datun Rd, Chaoyang District, Beijing 100101, China; ‡Graduate University of Chinese Academy of Sciences, Beijing 100049, China; and §Merck Research Laboratories, WP26A-4000, 770 Sumneytown Pike, West Point, PA 19486-0004 Communicated by Joan Wennstrom Bennett, Rutgers, The State University of New Jersey, New Brunswick, NJ, March 27, 2007 (received for review October 28, 2006) Among fungi, the basic life strategies are saprophytism, parasitism, These trapping devices all capture nematodes by means of an and predation. Fungi in Orbiliaceae (Ascomycota) prey on animals adhesive layer covering part or all of the device surfaces. The by means of specialized trapping structures. Five types of trapping constricting ring (CR), the fifth and most sophisticated trapping devices are recognized, but their evolutionary origins and diver- device (Fig. 1D) captures prey in a different way. When a gence are not well understood. Based on comprehensive phylo- nematode enters a CR, the three ring cells are triggered to swell genetic analysis of nucleotide sequences of three protein-coding rapidly inwards and firmly lasso the victim within 1–2 sec. genes (RNA polymerase II subunit gene, rpb2; elongation factor 1-␣ Phylogenetic analysis of ribosomal RNA gene sequences indi- ␣ gene, ef1- ; and ß tubulin gene, bt) and ribosomal DNA in the cates that fungi possessing the same trapping device are in the internal transcribed spacer region, we have demonstrated that the same clade (3, 8–11).
    [Show full text]
  • Phylogeny and Systematics of the Genus Calonectria
    available online at www.studiesinmycology.org Studies in Mycology 66: 31–69. 2010. doi:10.3114/sim.2010.66.03 Phylogeny and systematics of the genus Calonectria L. Lombard1*, P.W. Crous2, B.D. Wingfield3 and M.J. Wingfield1 1Department of Microbiology and Plant Pathology, Tree Protection Co-operative Programme, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria 0002, South Africa; 2CBS-KNAW Fungal Biodiversity Centre, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands; 3Department of Genetics, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria 0002, South Africa *Correspondence: Lorenzo Lombard, [email protected] Abstract: Species of Calonectria are important plant pathogens, several of which have a worldwide distribution. Contemporary taxonomic studies on these fungi have chiefly relied on DNA sequence comparisons of the β-tubulin gene region. Despite many new species being described, there has been no phylogenetic synthesis for the group since the last monographic study almost a decade ago. In the present study, the identity of a large collection of Calonectria isolates from various geographic regions was determined using morphological and DNA sequence comparisons. This resulted in the discovery of seven new species; Ca. densa, Ca. eucalypti, Ca. humicola, Ca. orientalis, Ca. pini, Ca. pseudoscoparia and Ca. sulawesiensis, bringing the total number of currently accepted Calonectria species to 68. A multigene phylogeny was subsequently constructed for all available Calonectria spp., employing seven gene regions, namely actin, β-tubulin, calmodulin, histone H3, the internal transcribed spacer regions 1 and 2 and the 5.8S gene of the ribosomal RNA, 28S large subunit RNA gene and translation elongation 1-alpha.
    [Show full text]
  • Preliminary Classification of Leotiomycetes
    Mycosphere 10(1): 310–489 (2019) www.mycosphere.org ISSN 2077 7019 Article Doi 10.5943/mycosphere/10/1/7 Preliminary classification of Leotiomycetes Ekanayaka AH1,2, Hyde KD1,2, Gentekaki E2,3, McKenzie EHC4, Zhao Q1,*, Bulgakov TS5, Camporesi E6,7 1Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, China 2Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai, 57100, Thailand 3School of Science, Mae Fah Luang University, Chiang Rai, 57100, Thailand 4Landcare Research Manaaki Whenua, Private Bag 92170, Auckland, New Zealand 5Russian Research Institute of Floriculture and Subtropical Crops, 2/28 Yana Fabritsiusa Street, Sochi 354002, Krasnodar region, Russia 6A.M.B. Gruppo Micologico Forlivese “Antonio Cicognani”, Via Roma 18, Forlì, Italy. 7A.M.B. Circolo Micologico “Giovanni Carini”, C.P. 314 Brescia, Italy. Ekanayaka AH, Hyde KD, Gentekaki E, McKenzie EHC, Zhao Q, Bulgakov TS, Camporesi E 2019 – Preliminary classification of Leotiomycetes. Mycosphere 10(1), 310–489, Doi 10.5943/mycosphere/10/1/7 Abstract Leotiomycetes is regarded as the inoperculate class of discomycetes within the phylum Ascomycota. Taxa are mainly characterized by asci with a simple pore blueing in Melzer’s reagent, although some taxa have lost this character. The monophyly of this class has been verified in several recent molecular studies. However, circumscription of the orders, families and generic level delimitation are still unsettled. This paper provides a modified backbone tree for the class Leotiomycetes based on phylogenetic analysis of combined ITS, LSU, SSU, TEF, and RPB2 loci. In the phylogenetic analysis, Leotiomycetes separates into 19 clades, which can be recognized as orders and order-level clades.
    [Show full text]
  • Orbilia Fimicola, a Nematophagous Discomycete and Its Arthrobotrys Anamorph
    Mycologia, 86(3), 1994, pp. 451-453. ? 1994, by The New York Botanical Garden, Bronx, NY 10458-5126 Orbilia fimicola, a nematophagous discomycete and its Arthrobotrys anamorph Donald H. Pfister range of fungi observed. In field studies, Angel and Farlow Reference Library and Herbarium, Harvard Wicklow (1983), for example, showed the presence of University, Cambridge, Massachusetts 02138 coprophilous fungi for as long as 54 months. Deer dung was placed in a moist chamber 1 day after it was collected. The moist chamber was main? Abstract: Cultures derived from a collection of Orbilia tained at room temperature and in natural light. It fimicola produced an Arthrobotrys anamorph. This ana? underwent periodic drying. Cultures were derived from morph was identified as A. superba. A discomycete ascospores gathered by fastening ascomata to the in? agreeing closely with 0. fimicola was previously re?side of a petri plate lid which contained corn meal ported to be associated with a culture of A. superba agar (BBL). Germination of deposited ascospores was but no definitive connection was made. In the present observed through the bottom of the petri plate. Cul? study, traps were formed in the Arthrobotrys cultures tures were kept at room temperature in natural light. when nematodes were added. The hypothesis is put Ascomata from the moist chamber collection are de? forth that other Orbilia species might be predators posited of in FH. nematodes or invertebrates based on their ascospore The specimen of Orbilia fimicola was studied and and conidial form. compared with the original description. The mor? Key Words: Arthrobotrys, nematophagy, Orbilia phology of the Massachusetts collection agrees with the original description; diagnostic features are shown in Figs.
    [Show full text]
  • ENTO-364 (Introducto
    K. K. COLLEGE OF AGRICULTURE, NASHIK DEPARTMENT OF AGRICULTURAL ENTOMOLOGY THEORY NOTES Course No.:- ENTO-364 Course Title: - Introductory Nematology Credits: - 2 (1+1) Compiled By Prof. T. B. Ugale & Prof. A. S. Mochi Assistant Professor Department of Agricultural Entomology 0 Complied by Prof. T. B. Ugale & Prof. A. S. Mochi (K. K. Wagh College of Agriculture, Nashik) TEACHING SCHEDULE Semester : VI Course No. : ENTO-364 Course Title : Introductory Nematology Credits : 2(1+1) Lecture Topics Rating No. 1 Introduction- History of phytonematology and economic 4 importance. 2 General characteristics of plant parasitic nematodes. 2 3 Nematode- General morphology and biology. 4 4 Classification of nematode up to family level with 4 emphasis on group of containing economical importance genera (Taxonomic). 5 Classification of nematode by habitat. 2 6 Identification of economically important plant nematodes 4 up to generic level with the help of key and description. 7 Symptoms caused by nematodes with examples. 4 8 Interaction of nematodes with microorganism 4 9 Different methods of nematode management. 4 10 Cultural methods 4 11 Physical methods 2 12 Biological methods 4 13 Chemical methods 2 14 Entomophilic nematodes- Species Biology 2 15 Mode of action 2 16 Mass production techniques for EPN 2 Reference Books: 1) A Text Book of Plant Nematology – K. D. Upadhay & Kusum Dwivedi, Aman Publishing House 2) Fundamentals of Plant Nematology – E. J. Jonathan, S. Kumar, K. Deviranjan, G. Rajendran, Devi Publications, 8, Couvery Nagar, Karumanolapam, Trichirappalli, 620 001. 3) Plant Nematodes - Methodology, Morphology, Systematics, Biology & Ecology Majeebur Rahman Khan, Department of Plant Protection, Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh, India.
    [Show full text]
  • The Phylogeny of Plant and Animal Pathogens in the Ascomycota
    Physiological and Molecular Plant Pathology (2001) 59, 165±187 doi:10.1006/pmpp.2001.0355, available online at http://www.idealibrary.com on MINI-REVIEW The phylogeny of plant and animal pathogens in the Ascomycota MARY L. BERBEE* Department of Botany, University of British Columbia, 6270 University Blvd, Vancouver, BC V6T 1Z4, Canada (Accepted for publication August 2001) What makes a fungus pathogenic? In this review, phylogenetic inference is used to speculate on the evolution of plant and animal pathogens in the fungal Phylum Ascomycota. A phylogeny is presented using 297 18S ribosomal DNA sequences from GenBank and it is shown that most known plant pathogens are concentrated in four classes in the Ascomycota. Animal pathogens are also concentrated, but in two ascomycete classes that contain few, if any, plant pathogens. Rather than appearing as a constant character of a class, the ability to cause disease in plants and animals was gained and lost repeatedly. The genes that code for some traits involved in pathogenicity or virulence have been cloned and characterized, and so the evolutionary relationships of a few of the genes for enzymes and toxins known to play roles in diseases were explored. In general, these genes are too narrowly distributed and too recent in origin to explain the broad patterns of origin of pathogens. Co-evolution could potentially be part of an explanation for phylogenetic patterns of pathogenesis. Robust phylogenies not only of the fungi, but also of host plants and animals are becoming available, allowing for critical analysis of the nature of co-evolutionary warfare. Host animals, particularly human hosts have had little obvious eect on fungal evolution and most cases of fungal disease in humans appear to represent an evolutionary dead end for the fungus.
    [Show full text]
  • Theory Manual Course No. Pl. Path
    NAVSARI AGRICULTURAL UNIVERSITY Theory Manual INTRODUCTORY PLANT NEMATOLOGY Course No. Pl. Path 2.2 (V Dean’s) nd 2 Semester B.Sc. (Hons.) Agri. PROF.R.R.PATEL, ASSISTANT PROFESSOR Dr.D.M.PATHAK, ASSOCIATE PROFESSOR Dr.R.R.WAGHUNDE, ASSISTANT PROFESSOR DEPARTMENT OF PLANT PATHOLOGY COLLEGE OF AGRICULTURE NAVSARI AGRICULTURAL UNIVERSITY BHARUCH 392012 1 GENERAL INTRODUCTION What are the nematodes? Nematodes are belongs to animal kingdom, they are triploblastic, unsegmented, bilateral symmetrical, pseudocoelomateandhaving well developed reproductive, nervous, excretoryand digestive system where as the circulatory and respiratory systems are absent but govern by the pseudocoelomic fluid. Plant Nematology: Nematology is a science deals with the study of morphology, taxonomy, classification, biology, symptomatology and management of {plant pathogenic} nematode (PPN). The word nematode is made up of two Greek words, Nema means thread like and eidos means form. The words Nematodes is derived from Greek words ‘Nema+oides’ meaning „Thread + form‟(thread like organism ) therefore, they also called threadworms. They are also known as roundworms because nematode body tubular is shape. The movement (serpentine) of nematodes like eel (marine fish), so also called them eelworm in U.K. and Nema in U.S.A. Roundworms by Zoologist Nematodes are a diverse group of organisms, which are found in many different environments. Approximately 50% of known nematode species are marine, 25% are free-living species found in soil or freshwater, 15% are parasites of animals, and 10% of known nematode species are parasites of plants (see figure at left). The study of nematodes has traditionally been viewed as three separate disciplines: (1) Helminthology dealing with the study of nematodes and other worms parasitic in vertebrates (mainly those of importance to human and veterinary medicine).
    [Show full text]