Pichia bruneiensis sp. nov., a biofilm-producing dimorphic yeast species isolated from flowers in Borneo.

Taxonomic analysis of five yeast strains isolated from Hibiscus flowers in Brunei (Borneo) is described. The strains represent a dimorphic, biofilm-producing, anamorphic budding yeast species for which the name Pichia bruneiensis is proposed. P. bruneiensis alternates between yeast and pseudohyphal modes of growth. The pseudohyphae form biofilms on the surface of liquid media and penetrate into solid substrates. The sequences of the D1/D2 domains of the large subunit rRNA genes, the internal transcribed spacer (ITS) regions and the 18S rRNA genes were identical in the five strains and indicated a close phylogenetic relationship with teleomorph species of the genus Pichia. In a phylogenetic analysis of these sequences, the closest relative of the new species was Pichia fermentans (6% nucleotide substitutions and indels in the D1/D2 domain). The type strain is 11-485(T) and has been deposited in the Centralbureau voor Schimmelcultures (Utrecht, the Netherlands) as CBS 12611(T), the National Collection of Agricultural and Industrial Micro-organisms (Budapest, Hungary) as NCAIM Y.02019(T) and the Culture Collection of Yeasts (Bratislava, Slovakia) as CCY 29-189-1(T). Mycobank no. MB800537.