<i>Zygosaccharomyces progenitor</i> sp. nov., a new yeast species associated with bees of the genera <i>Apis</i> and <i>Bombus</i>

A novel ascomycetous yeast species of the genus Zygosaccharomyces is proposed based on isolates obtained in Japan, Portugal and the USA, and on a combination of conventional DNA-barcode sequence analyses and whole-genome phylogenies. The new species is described as Z. progenitor sp. nov. (PYCC 7198T) and was found in association with bees (Apis mellifera and Bombus spp) and their honey, besides being also found in plants and soil. The novel species belongs to a Zygosaccharomyces subclade that also harbours Z. rouxii. Although the two species can be differentiated at the sequence level, they cannot be distinguished at the phenotypic level. As is typical in the genus, Z. progenitor sp. nov. produces spherical ascospores after cell conjugation.