Taxonomic and phylogenetic relationships of discomycetes emphasizing on pezizomycetes and leotiomycetes

Name: Ekanayaka, Anusha Hasini

keyword: Apothecia

MeSH: Phylogeny -- 253394

Classification :.DDC: QK623.D6

; Amyloidity

MeSH: Discomycetes -- 223455

MeSH: Fungi -- 231618

LCSH: Phylogeny -- 253394

LCSH: Discomycetes -- 223455

LCSH: Fungi -- 231618

Abstract: Abstract: Fungi are a fascinating group occurring in all eco-systems, especially as decomposers. In the tree of life fungi form a branch between the kingdoms Animalia and Plantae. Currently the kingdom Fungi includes approximately 2.2–3.8 million species. This figure excludes the undescribed species awaiting discovery in biodiversity hotspots in the tropics and other scarcely explored habitats. The division Ascomycota is a large group of fungi within the kingdom fungi, which forms asci within their fruiting bodies, which are called as ascomata. Ascomycota produce different ascomatal types. Among them there are three major types: apothecia, perithecia and cleistothecia. Apothecia are open structures which are often cup or disc-shaped. Cleistothecia and perithecia are closed structures which are flask or globose in shape. In the early schemes of classification for the Ascomycota, apothecia forming ascomycetes were placed within the class discomycetes, while pericthecia and cleistothecia forming fungi were classified under pyrenomycetes. The modern taxonomy based on molecular data did not recognized discomycetes or pyrenomycetes as a monophyletic group and they spread within in currently known classes of Ascomycota. Currently, the apothecial forming ascomycetes: discomycetes are a major artificial group within the Ascomycota which signify around 25% of all known taxa. This study is undertaken to investigate where does discomycetes position itself within ascomycetes using dual taxonomic approach (morphological and molecular). Fungal specimens associated with various hosts in terrestrial habitats were collected from Italy, Russia, Thailand, the UK and Uzbekistan. They were morphologically examined and their DNA sequence data from rDNA and protein genes (ITS, LSU, SSU, TEF and RPB2) were analyzed to verify their identity and phylogenetic affinities to better assess their natural placement. This study provides a historical perspective of discomycetes, notes on their morphology (including both asexual and sexual morphs), ecology and importance, an outline of discomycete families and a synoptic cladogram of currently accepted families in Ascomycota showing their systematic position. I also calculated evolutionary divergence times for major discomycetous taxa based on phylogenetic relationships using a combined LSU, SSU and RPB2 dataset from 175 strains and fossil data. Our results confirm that discomycetes are found in two major subphyla of the Ascomycota: Taphrinomycotina and Pezizomycotina. The taxonomic placement of the major discomycete taxa is briefly discussed. The most basal group of discomycetes is the class Neolectomycetes, which diverged from other Taphrinomycotina around 417 MYA (216–572), and the most derived group of discomycetes, the class Lecanoromycetes, diverged from Eurotiomycetes around 340 MYA (282–414). Further clarifications based on type specimens, designation of epitypes or reference specimens from fresh collections, and multi-gene analyses are needed to determine the taxonomic arrangement of many discomycetes. In modern classification, the operculate discomycetes are classified within class Pezizomycetes, although this feature has been lost in some Pezizomycetes. This study reviews 21 families of Pezizomycetes including five new families, which are introduced here, viz. Kallistoskyphaceae, Pseudombrophilaceae, Pulvinulaceae, Strobiloscyphaceae and Tarzettaceae. Moreover, this study provides a well-resolved backbone tree based on phylogenetic analysis of five combined loci. Descriptions and illustrations of representative taxa for the families are provided from collections made in China, Thailand and the UK, herbarium material from international fungaria (FH, FLAS, H, HKAS and MA) and the literature. Pezizales separates into six major clades. New sequence data belonging to ITS, LSU, SSU, TEF, RPB2 gene regions from 40 pezizalian species are provided here. Leotiomycetes are the inoperculate discomycetes within Ascomycota. This study provides a well-resolved backbone tree for the class Leotiomycetes based on phylogenetic analysis of five combined loci (ITS, LSU, SSU, TEF, and RPB2). The phylogenetic analysis shows Leotiomycetes separates into 19 clades, which can be recognized as orders and order level clades. Leotiomycetes include 44 families including nine new families (viz. Hamatocanthoscyphaceae fam. nov., Hyphodiscaceae fam. nov., Deltopyxiaceae fam. nov., Amicodiscaceae fam. nov., Solenopeziaceae fam. nov., Discinellaceae fam. nov., Hydrocinaceae fam. nov., Chlorospleniaceae fam. nov. and Bryoglossaceae fam. nov.) and 14 family-level clades (viz. Trizodia clade, Corticifraga-Calloriopsis clade, Micraspis clade, Flagellospora clade, Gelatinomyces clade, Epicladonia-Epithamnolia clade, Alatospora- Miniancora clade, Coleophoma-Parafabraea clade, Aquapoterium-Unguicularia clade, Patellariopsis clade, Phialocephala urceolata clade, Peltigeromyces clade, Bulgariella clade and Colipila clade). This study provides an outline of genera and families of Leotiomycetes, briefly discussing the systematic position of families/family-level clades and providing descriptions and illustrations of 50 Leotiomycetes taxa including six new genera and 22 new species, from collections made in Thailand, China, the UK, Italy, Russia and Uzbekistan. Phylogenetic analyses at a small scale from concatenated datasets (rDNA, TEF and RBP2) are provided where the backbone tree is insufficient to confirm the phylogenetic placement of collections. Recent studies showed the phylogenetic position of the discomycetous family Dactylosporaceae was unstable within the subphylum Pezizomycotina. Present study provides a stable phylogenetic placement for Dactylosporaceae within the class Eurotiomycetes and we introduce the new order: Dactylosporales to accommodate this family. We also introduce two new species to this family and their relationships with other taxa are represented in a multigene phylogeny. This study provides an updated backbone tree for Geoglossomycetes using ITS sequence data. Our collections during this study include Trichoglossum cf. octopartitum from China and a new species of Trichoglossum from Thailand, the latter named as T. septatum. According to morphological examination and molecular phylogenetic analyses of ITS sequence data, T. septatum diverges from other Trichoglossum species. Full descriptions, colour figures, and a phylogenetic tree to show the positions of T. cf. octopartitum and T. septatum are provided, and the two species are compared with allied taxa. The important morphological characteristics of Trichoglossum species are also summarized. Morphological and phylogenetic studies were carried out on new collections of Orbiliaceae from Thailand and revealed Hyalorbilia erythrostigma, Hyalorbilia inflatula, Orbilia stipitata sp. nov., Orbilia leucostigma and Orbilia caudata. Our new species is confirmed to be divergent from other Orbiliaceae species based on morphological examination and molecular phylogenetic analyses of ITS and LSU sequence data. Descriptions and figures are provided for the taxa which are also compared with allied taxa. During this study of discomycetes, we collected six Dothideomycetes specimens from China, Thailand and UK. Here we provide notes on these apothecial Dothideomycetes including four new species viz. Rhytidhysteron sp1, Rhytidhysteron sp2, Patellaria kevinhydeii and Patellaria microspora. Present study, lichenized discomycetes collected from northern Thailand, southern China, the UK, Ukraine and Russia are documented and new taxa introduced. Taxonomic studies of these taxa were carried out using both morphology and molecular data. The phylogenetic relationships of these taxa were inferred using LSU rDNA and ITS rDNA or combined analysis of these gene regions. Notes on 19 lichenized discomycetes taxa are compiled in this paper, including seven new species.

Mae Fah Luang University. Learning Resources and Educational Media Center

Address: CHIANG RAI

Email: library@mfu.ac.th

Name: Hyde Kevin David

Role: Advisor

Created: 2018

Modified: 2567-01-29

Issued: 2023-10-11

วิทยานิพนธ์/Thesis

application/pdf

CallNumber: QK623.D6 E367t 2018

eng

DegreeName: Doctor of Philosophy

Level: Doctoral Degree

Descipline: Biosciences

Grantor: Mae Fah Luang University

©copyrights Mae Fah Luang University

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