Pseudodidymellaceaefam. nov.: Phylogenetic affiliations of mycopappus-like genera inDothideomycetes

Abstract

The familial placement of four genera, Mycodidymella, Petrakia, Pseudodidymella, and Xenostigmina, was taxonomically revised based on morphological observations and phylogenetic analyses of nuclear rDNA SSU, LSU, tef1, and rpb2 sequences. ITS sequences were also provided as barcode markers. A total of 130 sequences were newly obtained from 28 isolates which are phylogenetically related to Melanommataceae (Pleosporales, Dothideomycetes) and its relatives. Phylogenetic analyses and morphological observation of sexual and asexual morphs led to the conclusion that Melanommataceae should be restricted to its type genus Melanomma, which is characterised by ascomata composed of a well-developed, carbonaceous peridium, and an aposphaeria-like coelomycetous asexual morph. Although Mycodidymella, Petrakia, Pseudodidymella, and Xenostigmina are phylogenetically related to Melanommataceae, these genera are characterised by epiphyllous, lenticular ascomata with well-developed basal stroma in their sexual morphs, and mycopappus-like propagules in their asexual morphs, which are clearly different from those of Melanomma. Pseudodidymellaceae is proposed to accommodate these four genera. Although Mycodidymella and Xenostigmina have been considered synonyms of Petrakia based on sexual morphology, we show that they are distinct genera. Based on morphological observations, these genera in Pseudodidymellaceae are easily distinguished by their synasexual morphs: sigmoid, multi-septate, thin-walled, hyaline conidia (Mycodidymella); globose to ovoid, dictyosporus, thick-walled, brown conidia with cellular appendages (Petrakia); and clavate with a short rostrum, dictyosporus, thick-walled, brown conidia (Xenostigmina). A synasexual morph of Pseudodidymella was not observed. Although Alpinaria was treated as member of Melanommataceae in a previous study, it has hyaline cells at the base of ascomata and pseudopycnidial, confluent conidiomata which is atypical features in Melanommataceae, and is treated as incertae sedis.

Two new species of Gloniopsis (Hysteriales, Ascomycota) from clinical specimens: Morphological and molecular characterisation

“…31 However, the coelomycetous fungus Aposphaeria is currently included in Melanommataceae, a different family within the order Pleosporales. 36 The molecular studies regarding Gloniopsis reveal that is a polyphyletic fungus of unclear taxonomy, 7,8,31 and our study confirms the previous state after analysing two phylogenetic markers.…”

Collapsimycopappus: A new leaf pathogen with mycopappus‐like propagules in Mycosphaerellaceae

“…A mycopappus‐like propagule may have evolved at least three times in the Ascomycota: Mycosphaerellaceae (Capnodiales, Dothideomycetes; this study), Pseudodidymellaceae (Pleosporales, Dothideomycetes; Funk & Dorworth, ; Gross et al., ; Hashimoto et al., ; Wei et al., , ) and Sclerotiniaceae (Helotiales, Leotiomycetes; Redhead & White, ; Suto & Kawai, ; Suto & Suyama, ; Takahashi et al., ). This appears to have resulted from convergent evolution of a similar ecological function, such as rain‐splash dispersal across the leaf surface.…”

“…The mycopappus‐like propagules of these fungi have been considered as contributors to secondary infection on host leaves due to their high inoculum potential. Therefore, they play an important role in disease development (Hashimoto et al., ; Wei et al., ). The hyphal appendages of mycopappus‐like propagules often separate into part spores when they mature, and the spores are able to germinate individually (Figure u).…”

“…"Mycosphaerella" polygoni-cuspidati is known to cause leaf spot disease in Fallopia japonica (Houtt.) Ronse Decr., and its life cycle involving a sexual morph and spermatial stage has been described (Kurose et al, 2009(Kurose et al, , 2016 Funk & Dorworth, 1987;Gross et al, 2017;Hashimoto et al, 2017;Wei et al, 1997Wei et al, , 1998 and Sclerotiniaceae (Helotiales, Leotiomycetes;Redhead & White, 1985;Suto & Kawai, 2000;Suto & Suyama, 2005;Takahashi et al, 2006). This appears to have resulted from convergent evolution of a similar ecological function, such as rain-splash dispersal across the leaf surface.…”

“…More than 70 fungi are known as pathogens of plant species in Styracaceae (Farr & Rossman, ), but none are similar to the fungus described here. Several mycopappus‐like genera have been reported in Pseudodidymellaceae (Dothideomycetes; Funk & Dorworth, ; Gross et al., ; Hashimoto, Matsumura, Hirayama, Fujimoto, & Tanaka, ; Wei, Harada, & Katumoto, , ) and in Sclerotiniaceae (Leotiomycetes; Redhead & White, ; Suto & Kawai, ; Suto & Suyama, ; Takahashi, Matsushita, Hogetsu, & Harada, ). The present fungus differs from other mycopappus‐like genera by having melanized propagules with hyphal appendages that collapse at maturity.…”