Ascoma development and phylogeny of an apothecioid dothideomycete, Catinella olivacea

Abstract

Catinella olivacea is a discomycetous fungus often found fruiting within cavities in rotting logs. Because this habitat would lack the air currents upon which discomycete species normally rely for the dispersal of their forcibly ejected ascospores, we suspected an alternative disseminative strategy might be employed by this species. An examination of the development of the discomycetous ascomata in pure culture, on wood blocks, and on agar showed that the epithecium was gelatinous at maturity and entrapped released ascospores in a slimy mass. We interpreted this as an adaptation for ascospore disperal by arthropods. Developmental data also showed that C. olivacea was unusual among other discomycetes in the Helotiales (Leotiomycetes). For example, the ascoma developed from a stromatic mass of meristematically dividing cells and involved the formation of a uniloculate cavity within a structure better considered an ascostroma than an incipient apothecium. Furthermore, the ascus had a prominent ocular chamber and released its ascospores through a broad, bivalvate slit. These features, along with phylogenetic analyses of large subunit and small subunit rDNA, indicated that this unusual apothecial fungus is, surprisingly, more closely affiliated with the Dothideomycetes than the Leotiomycetes.

Freshwater Ascomycetes: Minutisphaera (Dothideomycetes) revisited, including one new species from Japan

“…We also included Catinella olivacea, a discomycetous fungus that grows on rotting logs. Catinella olivacea earlier was placed in the Leotiomycetes based on the morphology, but a more recent study by Greif et al (2007) suggests that it is closely related to the Dothideomycetes, where it remains incertae sedis at the ordinal and familial rank. Results of the combined 83 taxa, two-gene (SSU + LSU) phylogeny suggested that the Minutisphaera clade did not share phylogenetic affinities with either members of Patellariaceae or C. olivacea (FIG.…”

Myconet Volume 14. Part One. Outline of Ascomycota—2009. Part Two. Notes on Ascomycete Systematics. Nos. 4751–5113

“…It is placed in Lecanoromycetes incertae sedis. Greif et al (2007) presented evidence from ascomal ontogeny and nuclear ribosomal DNA data that this genus, previously placed in Dermateaceae, belongs in Dothideomy-cetes. The ordinal placement could not be resolved and it is regarded as Dothideomycetes incertae sedis.…”

Gelatinomyces siamensis gen. sp. nov. (Ascomycota, Leotiomycetes, incertae sedis) on bamboo in Thailand

“…To construct the phylogenetic tree, the analysis was modified from Greif et al (2007), instead of using two taxa, Orbilia auricolor and Scutellinia scutellata as outgroup, only O. auricolor was employed. The sequence data of the Siamese Jelly-ball were aligned by ClustalX2 with sequences of 60 species retrieved from GenBank (www.ncbi.nlm.nih.gov) representing different classes of ascomycete fungi, including Arthoniomycetes , Dothideomycetes , Eurotiomycetes , Le-canoromycetes , Leotiomycetes , Lichinomycetes, and Sor-dariomycetes, where both SSU and LSU sequences data were available (Table 2), and manually edited by MEGA 5.05.…”