Description of Millerago gen. nov. based on taxogenomic analysis, with two new species, Millerago phaffii f.a., sp. nov. and Millerago galiae f.a., sp. nov.

Abstract

Four yeast isolates obtained from tree bark and fermenting sap of Quercus spp. and insects in Colombia and Japan were phylogenetically related to Candida galis based on analyses of the sequences of the internal transcribed spacer (ITS) region and the D1/D2 domains of the large subunit rRNA gene. The novel species differs from C. galis by 20 nt substitutions and 5 indels in the D1/D2 sequences. A phylogenomic analysis suggested that these species are related to Candida ficus, the genus Phaffomyces and a small clade containing Barnettozyma botsteinii, Barnettozyma siamensis and Candida montana. Our genomic analyses suggest that the novel species and C. galis should be separated in a novel yeast genus. We propose the genus Millerago gen. nov. to accommodate these species and the species Millerago phaffii f.a., sp. nov. (CBS 18021^T; MycoBank MB856172) to accommodate the Colombian and Japanese isolates. The Colombian isolate of M. phaffii differs from the Japanese isolates by three nt substitutions and one indel and two substitutions and one indel in the ITS and D1/D2 sequences, respectively, showing that they were conspecific. We also propose the new species Millerago galiae sp. nov. to validate this species according to the rules of the International Code of Nomenclature for algae, fungi and plants.