Crassoascoma gen. nov. (Lentitheciaceae, Pleosporales): Unrevealing Microfungi from the Qinghai-Tibet Plateau in China

Abstract

Microfungi associated with woody plants on the Qinghai–Tibet Plateau (QTP) were investigated, and four collections associated with Potentilla fruticosa were obtained from Gansu and Qinghai provinces in China. Morphologically, they line well with Lentitheciaceae in having subglobose to globose ascomata with brown setae on the papilla but can be distinguished from other genera by its superficial, globose, black, thick-walled ascomata, and fusiform, hyaline (rarely pale brown), one-septate ascospores, surrounded by an entire mucilaginous sheath. The phylogenetic analyses based on a combined SSU, ITS, LSU and TEF1-α sequence data showed that four isolates formed a monophyletic clade among the genera of Lentitheciaceae, and present as a distinct lineage (sister clade to Darksidea). Therefore, we introduce a new genus Crassoascoma, with C. potentillae as the type to accommodate these taxa. Detailed description and illustration are provided, and the establishment of new taxa is justified with morphology and phylogenetic evidence.