Dothideomycetes » Dothideomycetes, genera incertae sedis

Asteromassaria

Citation: Pem D et al. (2019) Mycosphere Notes 275-324: A morphotaxonomic revision and typification of obscure Dothideomycetes genera (incertae sedis). Mycosphere 10(1), 1115–1246

 

Asteromassaria Höhn., Sber. Akad. Wiss. Wien, Math.-naturw. Kl., Abt. 1 126(4-5): 368 (1917)

Saprobic on unidentified dry twigs in terrestrial habitat. Sexual morph: Ascomata solitary, scattered, or in small groups, immersed, erumpent, depressed globose or subglobose, medium to large, black, ostiolate. Ostiole papillate, opening via a minute slit or a small conical swelling in the bark. Peridium 1–layered, composed of small pigmented thick-walled compressed cells, with base consisting of small, pigmented, thick-walled cells of textura angularis and apex comprising comparatively large cells. Hamathecium of dense, cellular, filiform, broad, septate pseudoparaphyses, embedded in a gelatinous matrix. Asci 8-spored, bitunicate, fissitunicate, broadly cylindrical to broadly cylindro-clavate, with a short, narrow, thick pedicel, rounded at the apex with a small ocular chamber. Ascospores biseriate, partially overlapping, narrowly oblong with broadly to narrowly rounded ends, hyaline, 1-septate, constricted at septum, comprises smooth to verrucose spore wall without a mucilaginous sheath. Asexual morph: Scolicosporium macrosporium (Berk.) B.Sutton. Acervuli immersed in bark, brown, discrete, up to 200 μm diam., opening by irregular rupture of the overlaying tissues. Conidiophores cylindrical, 1–2 septate. Conidiogenous cells holoblastic, 1–2 annellate, cylindrical. Conidia fusoid, brown with paler or hyaline ends, 7–17 transversely septate, smooth-walled, with a tapered apex and truncate base.

 

Type species Asteromassaria macrospora (Desm.) Höhn.

 

Notes – The genus Asteromassaria was introduced by Höhnel (1917) with Asteromassaria macrospora (= Sphaeria macrospora Desm.) as the type species which was found on dry twigs in France. Presently, the genus Asteromassaria comprises 12 species (Index Fungorum 2019). Asteromassaria was placed in Pleomassariaceae by Lumbsch and Huhndorf (2010). It was then transferred to Morosphaeriaceae by Zhang et al. (2012). Later, based on morphology, Asteromassaria was moved to Dothideomycetes genera incertae sedis (Hyde et al. 2013, Kirk et al. 2013, Wijayawardene et al. 2014, Wijayawardene et al. 2018). We re-examined the holotype specimen of Asteromassaria macrospora under the code S-F73254 and it is distinct from species in Pleomassariaceae as the latter are characterized by brown to golden brown, muriform ascospores, frequently with a mucilaginous sheath while the type species of Asteromassaria has hyaline 1-septate ascospores without mucilaginous sheath. Molecular data are available but lacking for the type species. Only Internal transcribed spacer (ITS) gene and 18S ribosomal RNA gene regions have been deposited for Asteromassaria olivaceohirta and ITS gene for Asteromassaria berberidicola in GenBank. Based on a megablast search using the ITS sequence of Asteromassaria olivaceohirta, the closest matches in NCBI’s GenBank nucleotide database were Ulospora bilgramii strain CBS 110020, Neotestudina rosatii strain CBS 690.82, Zopfia rhizophila with identities 99%, 99% and 99% respectively. While those of Asteromassaria berberidicola reveals closest match to unidentified fungal endophyte (STRI: ICBG), Fungal sp. S12 ZLY-2010 and Hendersonia pinicola (EBJul30-4) with identities 89%, 89%, and 88% correspondingly. Based on our multigene-phylogenetic analyses (LSU, SSU, TEF, RPB2) using a strain of Asteromassaria pulchra (CBS 124082), the latter clusters as an independent lineage close to species of Morosphaeriaceae (data not shown). It is clear that the genus Asteromassaria is distinct from all species in the Dothideomycetes. However, more sequences are required to solve its correct taxonomic placement hence, we retain Asteromassaria in Dothideomycetes, genera incertae sedis.

 

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