Rhodotorula silvicola sp. nov., a new yeast species from plant-associated substrates and mushroom

Abstract

An orange-coloured yeast strain was recently isolated from rotted leaves in Zunyi City, Guizhou Province, PR China. Phylogenetic analysis revealed that this strain shares identical or similar sequences with no more than two to three nucleotide substitutions in both the 26S rDNA D1/D2 domains and the internal transcribed spacer (ITS) region with three other strains isolated from decayed wood in Indonesia, mushroom in Thailand and a plant of the genus Opuntia in the Bahamas. Therefore, these strains are conspecific. And they are most closely related to Rhodotorula paludigena but exhibit sequence divergences of 2.1-2.6% in the 26S rDNA D1/D2 domains and 2.9-3.2% in the ITS region. Physiologically, strain CGMCC 2.7770 differs from R. paludigena in its ability to assimilate maltose, l-arabinose and citric acid. Both the phylogenetic analysis and phenotypic characteristics indicate that those four strains represent a novel species in the genus Rhodotorula, for which the name Rhodotorula silvicola sp. nov. is proposed (holotype CGMCC 2.7770^T).

Keywords: Rhodotorula silvicola sp. nov.; basidiomycetous yeast; phylogeny; taxonomy.

Fig. 1.. Maximum likelihood phylogenetic tree based on the combined sequences of the 26S rDNA D1/D2 domains and the ITS region showing the phylogenetic placement of the novel species R. silvicola sp. nov. Bootstrap values≥70% are shown on the branches of the tree. Three species, Farysia acheniorum, Ustilago maydis and Sporobolomyces roseus, are used as the outgroup. Type strains are denoted with a superscripted ‘T’. Bar, 0.02 substitutions per nucleotide position.

Fig. 2.. The morphology of R. silvicola sp. nov. strain CGMCC 2.7770^T observed on YPD agar after 1 week at 20 °C includes colony morphology (a) and vegetative cells (b). Bars: 10 µm.