Taxonomy and phylogeny of dematiaceous coelomycetes and a naming asexual fungi

Name: Wijayawardene, Don Nalin Nilusha

Organization : Mae Fah Luang University

keyword: Fungi

LCSH: Fungi

Classification :.LCCS: QK601

LCSH: Reproduction, Asexual

Abstract: Coelomycetes are an artificial taxonomic group, which produce conidia inside a cavity i.e. conidiomata. Based on structure and origin of conidiomata, coelomycetes are distinct from the other groups of asexual fungi, the hyphomycetes. Pycnidia and acervuli have been treated as the conidiomatal types of coelomycetes, while sporodochia and synnemata are considered as conidiomata of hyphomycetous fungi. However, several genera share sporodochium-like conidiomata, which makes confusions among taxonomists. Conidiogenous cells are cells which produce conidia and several modes of conidiogenesis process have been recognized. In traditional taxonomy, the types of conidiomata and mode of conidiogenesis have been recognized as important characters. Naming of taxa was previously based on morphology and host association, but it caused proliferation of names, and produced taxa with unclear generic and species boundaries e.g. Camarosporium, Coniothyrium, Diplodia, Microsphaeropsis. Further, several genera have been linked with sexual morphs as both morphs co-occur on the same host material. The lack of databases and identification manuals caused problems to identify genera and species. This study provides taxonomic notes and descriptions for 235 dematiaceous coelomycetes. During the research, 92 new collections have been made and ten new genera (viz. Apiculospora, Didymellocamerosporium, Melanocamarosporium, Melnikia, Paulkirkia, Phragmocamarosporium, Forliomyces, Suttonomyces, Paracamarosporium, Pseudocamarosporium), 35 new species and two new combinations were introduced. Sixty-eight genera and 69 genera have been illustrated based on fresh collections and herbarium materials respectively. Seventy-one genera have been illustrated by line drawings based on the literature. Phylogenetic analyses were carried out to show the placement of dematiaceous coelomycetes in Dothideomycetes, Leotiomycetes and Sordariomycetes based on LSU, SSU, RPB2 and TEF1-α gene regions. Further, separate analyses were carried out to show the placement of genera in particular taxonomic hierarchy (i.e. Botryosphaeriaceae, Capnodiales, Diaporthales, dichomera-like taxa, Diplodia, Massarineae, Seimatosporium, Seiridium, Xylariomycetidae). Among 235 dematiaceous coelomycetes, 152 (65%) genera have DNA sequence data, thus, their taxonomic placement in natural classification system is listed as an outline. However, still, 83 genera lack DNA sequence data, hence, they are treated as Ascomycota, genera incertae sedis. The genus Camarosporium was linked with Botryosphaeriales, Cucurbitariaceae and Leptosphaeriaceae. In this study, Camarosporium sensu stricto has been recognized as a distinct phylogenetic lineage in Pleosporineae, Pleosporales. Camarosporium-like taxa are polyphyletic in Pleosporales, thus, introduced Didyme-llocamerosporium (in Didymellaceae), Pseudocamarosporium and Paracamarosp-orium (in Didymosphaeriaceae), Melanocamarosporium (in Melanommataceae), Sut-tonomyces (in Massarinaceae). Phragmocamarosporium was introduced to accomm-odate two collections from China and Germany, which have only phragomospore conidia. Phylogenetic analyses show that Phragmocamarosporium resides in Len-titheciaceae. Coniothyrium-like taxa are also polyphyletic in Pleosporales. Coniothyrium sensu stricto resides in Coniothyriaceae and two new collections are introduced as Paulkirkia (in Floricolaceae) and Forliomyces (Sporormiaceae). Pleomorphism is shown by several fungi throughout their life cycle, thus, causing confusions among taxonomists and pathologists. The dual nomenclature system was proposed by Saccardo (1904) and International Botanical Congress accepted it as Article 59. Thus, pleomorphic fungi which show two morphs were given two names and the links between two names were built based on host association, culture based methods and molecular methods. However, taxonomists suggest adopting only one name between two names, thus, the one fungus one name concept was proposed. This study proposes one name for pleomorphic Dothideomycetes and summarizes the name changes of dematiaceous coelomycetes.

Mae Fah Luang University. The Learning Resources and Education Media Center

Address: Chiang Rai

Email: library@mfu.ac.th

Name: Kevin David Hyde

Role: Advisor

Name: Ekachai Chukeatirote

Role: Co-Advisor

Created: 2015

Issued: 2016

Modified: 2020-04-27

Issued: 2016-12-15

วิทยานิพนธ์/Thesis

application/pdf

CallNumber: Thesis QK601 W662t 2015

eng

DegreeName: Dotor of Philosophy

Level: Doctoral Degree

Descipline: Biosciences

Grantor: Mae Fah Luang University

©copyrights Mae Fah Luang University

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