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

Abstract

Abstract Two fungal strains (K-2T 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-2T and S1 differed from their closely related species, such as Talaromyces assiutensis, and T. trachyspermus, by exhibiting 7%-7.88% sequence divergence (30–36 nt substitutions and 4–9 gaps). Phylogenetic analyses based on single and concatenated alignments of the ITS gene, the β-tubulin (benA) gene, the calmodulin (cam) gene, and the second-largest subunit fragment of RNA polymerase II (rpb2) gene showed that the isolates K-2T and S1 were clustered together with other species of the genus Talaromyces 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 validly published names by morphological and physiological characteristics, for example, growing at 4–50°C with pH 1.5–12. Based on phylogenetic, morphological, and physicochemical properties, they represent a novel species in the genus Talaromyces, for which the name Talaromyces sedimenticola sp. nov. is proposed. The type strain is K-2T (= GDMCC 3.746 = JCM 39451).