Cyberlindnera sylvatica sp. nov., a yeast species isolated from forest habitats

Five yeast strains isolated from forest habitats in Hungary and Germany were characterized phenotypically and by sequencing of the D1/D2 domain of the large subunit rRNA gene and the ITS1-5.8S-ITS2 (ITS) region of the rRNA gene. The strains have identical D1/D2 domain and ITS region sequences. By sequence comparisons, Candida mycetangii and Candida maritima were identified as the closest relatives among the currently recognized yeast species. The DNA sequences of the investigated strains differ by 1.2 % (six substitutions) in the D1/D2 domain and by 3.5 % (12 substitutions and eight indels) in the ITS region from the type strain of C. mycetangii (CBS 8675^T) while by 1.2 % (six substitutions and one indel) in the D1/D2 domain and by 7 % (32 substitutions and seven indels) in the ITS region from the type strain of C. maritima (CBS 5107^T). Because the intraspecies heterogeneity seems to be very low and the distance to the most closely related species is above the commonly expected level for intraspecies variability Cyberlindnera sylvatica sp. nov. (holotype, CBS 16335^T; isotype, NCAIM Y.02233^T; MycoBank no., MB 835268) is proposed to accommodate the above-noted five yeast strains. Phenotypically the novel species can be distinguished from C. mycetangii and C. maritima by the formation of ascospores. Cyberlindnera sylvatica forms one or two hat-shaped ascospores per ascus on many different media as well as well-developed pseudohyphae and true hyphae. Additionally, we propose the transfer of three anamorphic members of the Cyberlindnera americana sub-clade to the genus Cyberlindnera as the following new taxonomic combinations Cyberlindnera maritima f.a., comb. nov., Cyberlindnera mycetangii f.a., comb. nov. and Cyberlindnera nakhonratchasimensis f.a., comb. nov.