Talaromyces sedimenticola sp. nov., isolated from the Mariana Trench.

Abstract

Two fungal strains (K-2^T and S1) were isolated from the deepest ocean sediment of the Challenger Deep located in the Mariana Trench. The internal transcribed spacer (ITS) gene sequences of the isolates K-2^T and S1 differed from those of closely related species, such as Talaromyces assiutensis and T. trachyspermus. Phylogenetic analyses based on single and concatenated alignments of the genes, namely ITS, β-tubulin (benA), calmodulin (cam), and the second-largest subunit fragment of the RNA polymerase II (rpb2) showed that the isolates K-2^T and S1 were clustered together with other Talaromyces species, such as T. trachyspermus and T. assiutensis, as evidenced by the position on a terminal branch with high bootstrap support. They could also be distinguished from their closest relatives with valid published names via morphological and physiological characteristics, for example, growth at 4 °C-50 °C with a pH in the range of 1.5-12. Based on their phylogenetic, morphological, and physicochemical properties, the isolates K-2^T and S1 represent a novel species in the genus Talaromyces, and the proposed name is Talaromyces sedimenticola sp. nov. The type strain is K-2^T (= GDMCC 3.746^T = JCM 39451^T).