Combined omics expose microbial niches of fungi and bacteria correlating with wine volatile profiles in Douro wine region

Wine microbial communities establish complex ecological ecosystems that modulate the formation of aroma compounds, but only a few studies sought for correlations between specific microorganisms and wine volatiles. The present study combined metabarcoding and metabolomics for identifying microbial niches of fungi and bacteria correlating with the volatile profiles of wines of 3 renowned cultivars of the emblematic Douro region. Three major microbial niches were identified throughout the spontaneous fermentation processes, and the Hanseniaspora-Saccharomyces succession timing was cultivar-dependent. The largest niche included Hanseniaspora, Aureobasidium, Alternaria, Rhodotorula, Sporobolomyces, Massilia, Bacillus, Staphylococcus and Cutibacterium, that positively correlated with 7 metabolites, namely, acetoin, isoamyl acetate, ethyl propanoate, c-3-hexenol, phenylethyl acetate and 4-ethylphenol. The fermentative yeasts S. cerevisiae, Torulaspora delbrueckii and Meyerozyma caribbica strongly correlated with gamma-butyrolactone, t-whiskylactone, isoamyl alcohol, ethyl decanoate, ethyl isobutyrate, diethyl succinate, isovaleric acid, 4-ethylguaiacol and 4-propylguaiacol. Lachancea quebecensis clustered with several pathogenic fungi (Penicillium citrinum, Erysiphe necator, Sclerotinia sclerotiorum, Aspergillus, Mycosphaerella tassiana) and bacteria (Pseudomonas spp., Bacteroides acidifaciens, Pantoea, Stenotrophomonas and Enhydrobacter), correlating positively with various monoterpenols and norisoprenoids including linalool and beta-ionone, besides with benzyl alcohol, diacetyl, isobutyl acetate, ethyl-vanillate and methyl vanillinate. Metabolite-microbiota correlations denoted cultivar specificities likely underlying regional aromatic signatures.