Integrated volatilomics and transcriptomics unravel key genes governing aroma variation in fresh fruiting bodies of six <i>Auricularia auricula</i> strains

Auricularia auricula is a commercially important edible fungus, and its aroma is a critical factor determining quality. However, the molecular mechanisms underlying volatile formation in fresh fruiting bodies remain unclear. Here, six major cultivated strains from Northeast China were analysed using metabolomic and transcriptomic approaches to characterise volatile organic compounds (VOCs) profiles and related biosynthetic pathways. VOCs emissions differed significantly among strains: “Yannongke 1” and “Huanyuan 8” produced higher total VOCs levels, with esters accounting for 42.69%-51.47%. Key compounds included pentyl propionate, 1-octen-3-ol, trans-2-hexenal, β-pinene, neral, and cis-pinane. (E)-4-decenal and trans-3-hexenoic acid mainly contributed to green and fruity notes. Integrated analyses identified three core pathways: the Ehrlich, lipoxygenase (LOX), and mevalonate pathways. Expression of genes encoding alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH), LOX, and terpene synthase (TPS) was strongly correlated with volatile profiles. These results reveal the VOCs metabolic landscape and regulatory mechanisms of aroma formation, providing valuable gene targets for flavour-directed molecular breeding of A. auricula.