Discovery and identification of a novel yeast species, Hanseniaspora drosophilae sp. nov., from Drosophila in Okinawa, Japan

<i>Hanseniaspora</i>, a genus of yeasts in which many species reproduce sexually, has attracted the attention of researchers because of its prevalence in diverse ecological niches. Building on our extensive collection efforts since 2020, three previously unknown yeast strains from wild <i>Drosophila</i> species trapped in ripe bananas in Okinawa, Japan, were isolated. Using a multifaceted approach, including physiological assessments and sequence analysis of the D1/D2 domain of the 26S LSU rRNA gene and the internal transcribed spacer (ITS) region, it was revealed that these strains are novel members of the genus <i>Hanseniaspora</i>. The three strains, JCM 36741^T, JCM 36742 and JCM 36748, had identical sequences in their respective D1/D2 and ITS regions, justifying their classification as a single species. Moreover, the new species exhibited a remarkable degree of sequence divergence from its closest relatives, differing by 7 nucleotide substitutions (1.28%) in the D1/D2 domain, 29 nucleotide substitutions and 4 gaps (4.08%) in the ITS regions. These substantial sequence differences highlight the distinctiveness of this novel species in the genus <i>Hanseniaspora</i>. Further analysis revealed physiological characteristics that distinguished the new species from its closest relative, <i>Hanseniaspora hatyaiensis</i> (nom. inval.). These findings culminated in the proposed name <i>Hanseniaspora drosophilae</i> sp. nov., which recognizes the unique ecological niche within the <i>Drosophila</i> microbiota. By uncovering this novel species, this study not only adds to the growing body of knowledge on yeast diversity but also sheds light on the intricate ecological relationships that shape microbial communities. The implications of this discovery extend beyond taxonomic boundaries, inviting further exploration of the evolutionary dynamics and ecological significance of yeast-fly interactions. We propose accommodating <i>H. drosophilae</i> sp. nov. in the genus <i>Hanseniaspora</i> with JCM 36741^T as the holotype. The MycoBank accession number is MB 853822.