Halophilic and thermotolerant Gymnoascus species from several special environments, China

Abstract

This study introduces three new Gymnoascus species (Gymnoascaceae, Onygenales), G. halophilus, G. stercorarius and G. thermotolerans, isolated from sediments in Chaka Salt Lake, compost and cornfield soil, respectively, in China, based on a polyphasic characterization including morphology, physiology and molecular phylogeny. Phylogenetic relationships were assessed based on the nuclear internal transcribed spacer (ITS = ITS1 + 5.8S + ITS2) region and a combined multilocus alignment of the ITS, 18S subunit rRNA gene and 28S subunit rRNA genes. Our study identified phylogenetic and phenotypic characters that differentiated the three new species from known species in the genus. Salinity and temperature tolerance tests revealed that G. halophilus was an obligate halophile while G. stercorarius and G. thermotolerans were halotolerant and thermotolerant. A key to accepted species of Gymnoascus is provided.

• molecular phylogeny
• morphology
• salt and heat tolerance
• taxonomy

Acknowledgments

This work was financially supported by NSFC ( 31322001) and Fundamental Research on Science and Technology, MOST (2014FY120100).

We are grateful for the help of Dr Roger G. Shivas, who provided valuable suggestions for this work during his academic visit to China (financed by NSFC 31110103906).