Neostagonosporellasichuanensis gen. et sp. nov. (Phaeosphaeriaceae, Pleosporales) on Phyllostachysheteroclada (Poaceae) from Sichuan Province, China

Abstract

Neostagonosporellasichuanensis sp. nov. was found on Phyllostachysheteroclada collected from Sichuan Province in China and is introduced in a new genus Neostagonosporella gen. nov. in this paper. Evidence for the placement of the new taxon in the family Phaeosphaeriaceae is supported by morphology and phylogenetic analysis of a combined LSU, SSU, ITS and TEF 1-α DNA sequence dataset. Maximum-likelihood, maximum-parsimony and Bayesian inference phylogenetic analyses support Neostagonosporella as a distinct genus within this family. The new genus is compared with related genera of Phaeosphaeriaceae and full descriptions and illustrations are provided. Neostagonosporella is characterised by its unique suite of characters, such as multiloculate ascostromata and cylindrical to fusiform, transversely multiseptate, straight or curved ascospores, which are widest at the central cells. Conidiostromata are multiloculate, fusiform to long fusiform or rhomboid, with two types conidia; macroconidia vermiform or subcylindrical to cylindrical, transversely multiseptate, sometimes curved, almost equidistant between septa and microconidia oval, ellipsoidal or long ellipsoidal, aseptate, rounded at both ends. An updated phylogeny of the Phaeosphaeriaceae based on multigene analysis is provided.

Keywords: 2 new taxa; bambusicolous fungi; phylogeny; stem spot; taxonomy.

Figure 1.

Phylogram generated from maximum likelihood analysis (RAxML) based on combined LSU, SSU, ITS and TEF 1-α sequenced data of taxa from the family Phaeosphaeriaceae and other representative species in Pleosporineae and Massarineae. The tree is rooted to Cyclothyriellarubronotata (CBS 121892), C.rubronotata (CBS 141486), Didymosphaeriarubi-ulmifolii (MFLUCC 14-0024) and D.variabile (CBS 120014). Bootstrap support values of maximum parsimony and maximum likelihood (MPBP, left; MLBP, middle) equal to or greater than 70% and Bayesian posterior probabilities (BYPP, right) equal to or greater than 0.95 are provided. The type strains were highlighted in bold and the newly generated sequences are highlighted in red.

Figure 2.

Neostagonosporellasichuanensis (MFLU 18-1212, holotype). a аppearance of ascostromata on host b ascostroma c, d vertical section of ascostroma e, f close up of ascoma g peridium h trabeculate pseudoparaphyses and asci i–k asci l bitunicate asci, note ocular chamber m, n, q, r ascospores with mucilaginous sheath o, s germinated ascospores in lactate cotton blue reagent p, t colonies on PDA (p-from above, t-from below). Scale bars: 1 cm (a); 1 mm (b); 200 μm (c, d); 100 μm (e, f); 20 μm (g–k); 10 μm (l–o, q–s).

Figure 3.

Neostagonosporellasichuanensis (MFLU 18-1220, paratype). a appearance of conidiomata on host b, c vertical section of conidioma d pycnidia e peridium f, g conidiogenous cells and developing conidia h–l conidia m germinated conidium. Scale bars: 1 cm (a); 200 μm (b–d); 20 μm (e, f); 10 μm (g–m).