Pleurostomophora, an anamorph of Pleurostoma (Calosphaeriales), a new anamorph genus morphologically similar to Phialophora

Abstract

Pleurostoma ootheca (Calosphaeriales) was newly collected, and found to produce a Phialophora-like anamorph in culture, which was morphologically similar to Phialophora (Ph.) repens and Ph. richardsiae. The close relationship among these three species was confirmed on the basis of sequence analysis of the 5.8S nuclear ribosomal RNA gene and its flanking internal transcribed spacers (ITS1 and ITS2). Furthermore, molecular data from partial 18S small subunit (SSU) DNA, revealed these three species were not phylogenetically closely related to the type of Phialophora, Ph. verrucosa, which was nested in the Chaetothyriales clade. A new anamorph genus, Pleurostomophora (P.), was therefore proposed to accommodate these species. The formation of perithecia from single-ascospore isolates of Pleurostoma (Pl.) ootheca also showed it to have a homothallic mating system.