Trichosporon xylopini sp. nov., a hemicellulose-degrading yeast isolated from the wood-inhabiting beetle Xylopinus saperdioides

Four arthroconidium-producing yeasts were isolated from the gut of wood-inhabiting tenebrionid and passalid beetles. The rRNA genes of these yeast strains were sequenced, compared and analysed. The sequence results and other taxonomic characterizations placed two of the strains into Trichosporon porosum, and the remaining strains, EH024T and EH026 which were isolated from Xylopinus saperdioides (Coleoptera: Tenebrionidae), into a novel species of the genus Trichosporon in the Porosum clade. Strain EN6S23 was independently isolated from forest soil in Taiwan and was identified as the same novel species based on identical sequences in the internal transcribed spacers (ITS) and the D1/D2 region of the LSU rRNA gene and similar physiological characteristics to those of strains EH024T and EH026. The three strains can assimilate cellulose and xylan as sole carbon source, and are clearly distinguished from their closest taxon, T. porosum, by 14 nt differences in the ITS and D1/D2 region. These strains did not reproduce sexually under the laboratory conditions tested. The novel species is proposed as Trichosporon xylopini sp. nov. (type strain EH024T = ATCC MYA-4670T = CBS 11841T).