Sporobolomyces bannaensis, a novel ballistoconidium-forming yeast species in the Sporidiobolus lineage

Researchers isolated 130 yeast strains from plant leaves in Xishuang Banna, Yunnan Province, China, and identified five strains that formed pink colonies and asymmetric ballistoconidia as a novel species. Conventional taxonomic analysis, including morphological, physiological, and biochemical characterization, classified these strains in the genus Sporobolomyces. Molecular phylogenetic analysis of the 26S rDNA D1/D2 domain and internal transcribed spacer (ITS) sequences revealed that all five strains were conspecific and clustered within the Johnsonii clade of the Sporidiobolus lineage. The strains differed from the closely related species Sporobolomyces blumeae by approximately 3% in the D1/D2 domain and 8% in the ITS region. The major ubiquinone detected was Q-10. Based on sequence divergence and metabolic differences—particularly in assimilation patterns of inulin, ethanol, glycerol, and certain nitrogen compounds—the researchers proposed these strains represent a novel species, Sporobolomyces bannaensis sp. nov., with the type strain Y41T isolated from wilting Theobroma cacao leaves.

Key findings

• Five yeast strains isolated from tropical rainforest plant leaves in Banna, Yunnan Province form a novel species, Sporobolomyces bannaensis sp. nov., with pink colonies and asymmetric ballistoconidia
• Molecular phylogenetic analysis of D1/D2 and ITS rDNA sequences confirms the strains are conspecific and most closely related to Sporobolomyces blumeae within the Sporidiobolus lineage
• The novel species differs from S. blumeae by ~3% sequence divergence in the D1/D2 domain and shows distinct biochemical differences in assimilation of specific carbon and nitrogen compounds
• The type strain Y41T contains ubiquinone Q-10 and exhibits urease activity with maximum growth at 33-34°C