果香型葡萄酒酵母的发酵特征与转录组学研究

Studies on Fermentation Characteristics and Transcriptomics of Fruity-flavored Wine Yeast

为揭示果香型酵母香气物质代谢特征及调控机理,以果香型酵母SSF12为研究对象,以另一株果香表现较差的菌株NGF6作为对照,研究它们在葡萄酒发酵过程中的转录组学差异,以及发酵液的理化指标、香气物质含量及感官特性等发酵特征。结果表明:SSF12糖利用度和发酵度高,发酵液中酯类、醇类、萜烯类物质含量高于NGF6,醛类、脂肪酸含量低于NGF6,果香感官特性明显优于NGF6。转录组学分析显示:SSF12相较于NGF6有434个基因差异表达(包括290个上调基因和144个下调基因)。代谢通路分析表明:SSF12在碳水化合物(尤其是糖类、高级醇、酯类)代谢、核酸代谢途径有更多的上调基因,可能表现更突出。NGF6在乙醛合成、脂肪酸合成、部分氨基酸代谢途径的上调基因更多。ADH2,ADH6,ALD3,ATF2等差异表达基因与香气物质代谢密切相关,可作为基因工程改良酵母的研究基因,为果香型酵母的选育与改造提供参考。

The fruity-flavored yeast SSF12 was used as the research object and another strain NGF6 with poor fruity flavor was used as the control to study their transcriptomic differences in the process of wine fermentation.Combined with the physical and chemical indexes,aroma substances content and sensory characteristics of fermentation broth,the metabolic characteristics and related regulated mechanism of aroma substances of fruity yeast were revealed.Results showed that SSF12 had higher sugar utilization and fermentation degree.The contents of esters,alcohols and terpenes in the fermentation broth of SSF12 were higher than that of NGF6,while the contents of aldehydes and fatty acids were lower than NGF6.Meanwhile,the fruity sensory characteristics of the fermentation broth of SSF12 were significantly better than that of NGF6.Transcriptomic analysis showed that there were 434 genes differentially expressed in SSF12 compared with NGF6(including 290 up-regulated genes and 144 down-regulated genes).KEGG analysis showed that SSF12 had more up-regulated genes in carbohydrate(especially sugars,higher alcohols and esters)metabolism and nucleic acid metabolism,thus might be more prominent in these pathways.NGF6 had more up-regulated genes in pathways of acetaldehyde synthesis,fatty acid synthesis and some amino acid metabolism.The differentially expressed genes such as ADH2,ADH6,ALD3,and ATF2 were closely related to aroma substances metabolism.So they can be used as candidate genes for wine aroma improvement.Results of this study might provide a reference for the breeding and strain improvement of fruity-flavored yeasts.