Oligotrophic fungi from a carbonate cave, with three new species of<i>Cephalotrichum</i>

Abstract

Oligotrophs are microorganisms that can grow in environments where concentrations of nutrients are low or even absent. Caves are typical oligotrophic environments distinctly characterised by constant low temperature, high humidity, scarcity of organic matter and darkness, which encompass a high diversity of fungi. In our investigation of microorganisms from carbonate caves in China, 169 strains belonging to at least 84 taxa were isolated using oligotrophic carbon free silica gel medium (SGM). Cephalotrichum appeared to be one of the dominant genera. Further morphological comparisons and molecular phylogenetic analyses using DNA sequences of four loci (LSU, ITS, TUB2 and EF-1α) revealed that the 30 strains of Cephalotrichum represent three new species, which are described and named C. guizhouense, C. laeve and C. oligotriphicum. This study also significantly improved our understanding on fungi being able to grow on carbon free medium, with the known species increased from 18 to 99.