Genetic and transcriptomic evidences suggestARO10genes are involved in benzenoid biosynthesis by yeast

Benzenoids are compounds associated with floral and fruity flavours in flowers, fruits and leaves and present a role in hormonal signalling in plants. These molecules are produced by the phenyl ammonia lyase pathway. However, some yeasts can also synthesize them from aromatic amino acids using an alternative pathway that remains unknown.Hanseniaspora vineaecan produce benzenoids at levels up to two orders of magnitude higher thanSaccharomycesspecies, so it is a model microorganism for studying benzenoid biosynthesis pathways in yeast. According to their genomes, several enzymes have been proposed to be involved in a mandelate pathway similar to that described for some prokaryotic cells. Among them, theARO10gene product could present benzoylformate decarboxylase activity. This enzyme catalyses the decarboxylation of benzoylformate into benzaldehyde at the end of the mandelate pathway in benzyl alcohol formation. Two homologous genes ofARO10were found in the two sequencedH.vineaestrains. In this study, nine otherH.vineaestrains were analysed to detect the presence and per cent homology ofARO10sequences by PCR using specific primers designed for this species. Also, the copy number of the genes was estimated by quantitative PCR. To verify the relation ofARO10with the production of benzyl alcohol during fermentation, a deletion mutant in theARO10gene ofSaccharomyces cerevisiaewas used. The two HvARO10paralogues were analysed and compared with other alpha-ketoacid decarboxylases at the sequence and structural level.