Taxonomy and phylogentic evolution of pleosporales

Name: Ariyawansa, Hiran Anjana

Organization : Mae Fah Luang University

keyword: Pleosporales

LCSH: Pleosporales

Classification :.LCCS: QK623.P68

Abstract: Pleosporales is a ubiquitous fungal order that includes saprobic, endophytic and pathogenic species associated with a wide variety of substrates, which is considered as the largest order in the Dothideomycetes, comprising a quarter of all dothideomycetous species. Several recent studies have provided the groundwork for classification in the Pleosporales and its allied families. Some studies have been based solely on morphological characterization and some have included molecular analysis. Even though there is a large body of work comprising taxonomic and phylogenetic studies, the majority of Families and genera hypothesized to be members of Pleosporales remain under-studied and poorly understood within a systematic framework. In this study, several confused families of Pleosporales are selected to evaluate their phylogeny, interfamilial relationships, and the morphological circumscription of each family. Diademaceae considered being a distinctive family in Pleosporales based on the ascomata opening via a flat, circular lid. We revisited the family Diademaceae based on available sequence data and morphology. Study concluded Diademaceae is characterized by ascomata opening with a flat circular lid, and fissitunicate, short orbicular frequently cylindrical, pedicellate asci. Ascospores are frequently circular in section but narrowing to one end with three or more transverse septa, without longitudinal septa, and mostly with a thick sheath. Based on molecular and morphological study, Clathrospora, Comoclathris and Diademosa are excluded from the family and referred to Pleosporaceae. Graphyllium is excluded from Diademaceae and tentatively placed in Hysteriaceae with uncertainty. The study accepts only Diadema in the family and concluded that the status of Diademaceae as a distinct family, based on the ascomata opening by a flat circular lid is thought to be doubtful. The new family Halojulellaceae and Halojullela gen. nov. are introduced to accommodate Julella avicenniae, a marine species in the suborder Pleosporineae, order Pleosporales based on combined gene analysis of the large and small subunits of the nuclear ribosomal RNA genes (LSU, SSU) and two protein coding genes RPB2 and TEF1coupled with morphology. Halojulellaceae and Halojulella are characterized by immersed to semi-immersed, clypeate ascomata, with short, papillate ostioles, cellular, pseudoparaphyses, 8-spored, fissitunicate, clavate to cylindrical asci with a well-developed apical apparatus, a club-like base and hyaline or golden brown, ellipsoidal, muriform ascospores and is typified by Halojulella avicenniae. Morphology together with DNA sequence data based on (ITS) with LSU, SSU and β-tubulin gene sequences, the taxonomy of the genera classified in Montagnulaceae and Didymosphaeriaceae are reassessed. The study synonymize Montagnulaceae under Didymosphaeriaceae and accept Alloconiothyrium, Bimuria, Deniquelata, Didymocrea, Didymosphaeria, Kalmusia, Karstenula, Letendraea, Montagnula, Neokalmusia, Paraconiothyrium, Paraphaeosphaeria, Phaeodothis and Tremateia in the reassessed family Didymosphaeriaceae. Furthermore study reveals one a new genus, Neokalmusia to accommodate the bambusicolous taxa Kalmusia brevispora and K. scabrispora, while two new species, Paraconiothyrium magnoliae, Letendraea cordylinicola and the sexual morph of Paraconiothyrium fuckelii, is also introduced. Additionally Julella and Barria are assigned to the family based on morphological likeness with Didymosphaeriaceae. Wilmia (previously referred to the Phaeosphaeriaceae) is synonymized under Letendraea (Didymosphaeriaceae). Importantly based on the phylogenetic analysis in combination with morphology and a review of literature Appendispora, Roussoella and Verruculina excluded from the family Didymosphaeriaceae. In order to establish evolutionary relationship and to resolve the polyphyletic nature of Pleospora and allied genera, 18S nrDNA, 28S nrDNA, ITS, GAPDH, RPB2 and TEF1-alpha genes were sequenced and analyzed phylogenetically. Multigene phylogenies strongly support the monophyletic nature of Pleosporaceae among the other families in Pleosporales, and the acceptance of the genera Alternaria, Bipolaris, Clathrospora, Comoclathris, Curvularia, Dactuliophora, Decorospora, Diademosa, Exserohilum, Extrawettsteinina, Gibbago, Macrospora, Neocamarosporium, Paradendryphiella, Porocercospora, Pseudoyuconia and Pyrenophora while Austropleospora, Dendryphion and Edenia are excluded from the family Pleosporaceae. Importantly the paraphyletic nature of Pleospora is resolved while two novel species, Alternaria murispora and Comoclathris sedi are introduced and sexual morph of Alternaria alternata is re-described and illustrated using modern concepts using fresh collections. Importantly we provide a well resolved backbone tree for the family so which can be used as a foundation, thus need to be updated in future studies with the availability of new sequence data. Sequentially to explain the importance of the epitypification and neotypification and to describes how to epitypify or neotypify species and examines the significance of this process are presented based on examples where taxa have been epitypified in past literatures. Furthermore a set of guidelines for epitypification for future workers and the benefits along with the problems of epitypification are discussed. As examples of epitypification or to provide reference specimens, new epitypes was designated for Paraphaeosphaeria michotii and reference specimens collected from different parts of the world are provided for Astrosphaeriella stellata, A. bakeriana, Phaeosphaeria elongata, Ophiobolus cirsii, and O. erythrosporus. We re-examined the genera Cucurbidothis, Dermatodothella, Dothideopsella, Grandigallia, Heterosphaeriopsis, Hyalosphaera, Hysteropeltella, Gloeodiscus, Navicella and Pleiostomellina which were previously been classified under Dothideomycetes incertae sedis. By re-examining the generic types of Dothideomycetes genera, incertae sedis which are generally poorly known thus we proposed higher level positions according to the morphology based on modern taxonomic concepts, but more importantly we illustrated the taxa so that they are better understood.

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

Address: Chiang Rai

Email: library@mfu.ac.th

Name: Kevin D. Hyde

Role: Advisor

Name: Ekachai Chukeatirote

Role: Co-Advisor

Created: 2014

Issued: 2015

Modified: 2020-04-03

Issued: 2015-10-12

วิทยานิพนธ์/Thesis

application/pdf

CallNumber: Thesis QK623.P68 A718t 2014

eng

DegreeName: Dotor of Philosophy

Level: Doctoral Degree

Descipline: Biosciences

Grantor: Mae Fah Luang University

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