A phylogenetic assessment and taxonomic revision of the thermotolerant hyphomycete genera Acrophialophora and Taifanglania

Abstract

We assessed the phylogenetic relationships of 19 isolates belonging to Acrophialophora and Taifanglania based on internal transcribed spacer (ITS), nuclear 18S subunit (nuc 18S) rDNA and β-tubulin sequences. Phylogenetic data showed that Acrophialophora and Taifanglania comprise a monophyletic clade, but did not support the distinction of two genera. Being the older and more frequently used name, Acrophialophora is adopted as the generic name and Taifanglania is treated as a synonym. The generic concept of Acrophialophora is emended to include the morphological characters formerly used to distinguish Taifanglania. Three new thermotolerant species isolated from soil samples in China are described and illustrated, (i) A. ellipsoidea, with solitary phialides tapering into thin necks and long chains of ellipsoidal to fusiform conidia, (ii) A. angustiphialis with single phialides terminal or lateral on hyphae, and long chains of ellipsoidal or fusiform conidia and, (iii) A. acuticonidiata with single phialides and fusiform conidia with acute ends. Phylogenetic analyses show that A. acuticonidiata, A. angustiphialis and A. ellipsoidea are most closely related to A. curticatenata, A. hechuanensis and A. major, respectively. Growth tests showed that the three new species are thermotolerant, with optimal growth temperatures of 37–40 C, and maximum growth temperatures near 50 C. A key to the accepted species of Acrophialophora is provided.