Complete mitochondrial DNA sequence of the yeast Zygosaccharomyces siamensis (Saccharomycetes: Saccharomycetales) from fermented honey of the Apis cerana japonica in Japan

Abstract

Japanese Apis cerana honey is believed to ferment due to the presence of some yeast. We analyzed the complete mitochondrial genome of Zygosaccharomyces siamensis, a yeast involved in fermenting honey. Zygosaccharomyces siamensis was obtained from the honey collected from A. cerana hives under traditional beekeeping in the forest of the Minabe-Tanabe Ume system in Wakayama Prefecture, Japan. Its mitochondrial genome was identified as a 23,184 bp circular molecule containing 8 protein-coding genes (PCGs), 24 tRNA genes, and 2 rRNA genes. The PCGs contained a common set of genes encoding ATPase subunits (ATP6, ATP8, and ATP9), three subunits of cytochrome C oxidase (COX1, COX2, and COX3), apocytochrome b (CYTB), and ribosome-associated protein (RPS3). In addition, two open-reading frames coding for LAGLIDADG endonucleases were predicted to be about 1100 bps. The average GC content was found to be 48.6%. The heavy strand was predicted to have 7 PCGs, 22 tRNA genes, and 2 rRNA genes, while the light strand was predicted to contain one PCG and two tRNA genes. Molecular phylogenetic analyses of the mitochondrial DNA genes strongly supported the result obtained from the phylogenetic analysis of partial ITS region sequences, grouping the monophyletic species within the genus Zygosaccharomyces. The complete mitochondrial DNA genome of this honey-fermenting yeast will provide useful information for understanding the basis of the honey fermentation process.