The complete genome of Blastobotrys (Arxula) adeninivorans LS3 - A yeast of biotechnological interest

Background: The industrially important yeast Blastobotrys (Arxula) adeninivorans is an asexual hemiascomycete phylogenetically very distant from Saccharomyces cerevisiae. Its unusual metabolic flexibility allows it to use a wide range of carbon and nitrogen sources, while being thermotolerant, xerotolerant and osmotolerant. Results: The sequencing of strain LS3 revealed that the nuclear genome of A. adeninivorans is 11.8 Mb long and consists of four chromosomes with regional centromeres. Its closest sequenced relative is Yarrowia lipolytica, although mean conservation of orthologs is low. With 914 introns within 6116 genes, A. adeninivorans is one of the most intron-rich hemiascomycetes sequenced to date. Several large species-specific families appear to result from multiple rounds of segmental duplications of tandem gene arrays, a novel mechanism not yet described in yeasts. An analysis of the genome and its transcriptome revealed enzymes with biotechnological potential, such as two extracellular tannases (Atan1p and Atan2p) of the tannic-acid catabolic route, and a new pathway for the assimilation of n-butanol via butyric aldehyde and butyric acid. Conclusions: The high-quality genome of this species that diverged early in Saccharomycotina will allow further fundamental studies on comparative genomics, evolution and phylogenetics. Protein components of different pathways for carbon and nitrogen source utilization were identified, which so far has remained unexplored in yeast, offering clues for further biotechnological developments. In the course of identifying alternative microorganisms for biotechnological interest, A. adeninivorans has already proved its strengthened competitiveness as a promising cell factory for many more applications.