Peltier Emilien, Vion Charlotte, Abou Saada Omar, Friedrich Anne, Schacherer Joseph, Marullo Philippe
Unité de Recherche Œnologie EA 4577, USC 1366 INRA, Bordeaux INP, ISVV, Université de Bordeaux, Bordeaux, France.
Biolaffort, Bordeaux, France.
Front Fungal Biol. 2021 Oct 18;2:733513. doi: 10.3389/ffunb.2021.733513. eCollection 2021.
The identification of natural allelic variations controlling quantitative traits could contribute to decipher metabolic adaptation mechanisms within different populations of the same species. Such variations could result from human-mediated selection pressures and participate to the domestication. In this study, the genetic causes of the phenotypic variability of the central carbon metabolism of were investigated in the context of the enological fermentation. The genetic determinism of this trait was found out by a quantitative trait loci (QTL) mapping approach using the offspring of two strains belonging to the wine genetic group of the species. A total of 14 QTL were identified from which 8 were validated down to the gene level by genetic engineering. The allelic frequencies of the validated genes within 403 enological strains showed that most of the validated QTL had allelic variations involving flor yeast specific alleles. Those alleles were brought in the offspring by one parental strain that contains introgressions from the flor yeast genetic group. The causative genes identified are functionally linked to quantitative proteomic variations that would explain divergent metabolic features of wine and flor yeasts involving the tricarboxylic acid cycle (TCA), the glyoxylate shunt and the homeostasis of proton and redox cofactors. Overall, this work led to the identification of genetic factors that are hallmarks of adaptive divergence between flor yeast and wine yeast in the wine biotope. These results also reveal that introgressions originated from intraspecific hybridization events promoted phenotypic variability of carbon metabolism observed in wine strains.
鉴定控制数量性状的天然等位基因变异有助于解读同一物种不同群体内的代谢适应机制。此类变异可能源于人类介导的选择压力，并参与驯化过程。在本研究中，在酿酒发酵的背景下，对[具体物种]中心碳代谢表型变异性的遗传原因进行了研究。通过使用属于该物种葡萄酒遗传组的两个菌株的后代，采用数量性状位点（QTL）定位方法，找出了该性状的遗传决定因素。共鉴定出14个QTL，其中8个通过基因工程在基因水平上得到验证。403个酿酒菌株中已验证基因的等位基因频率表明，大多数已验证的QTL具有涉及花酵母特异性等位基因的等位变异。这些等位基因由一个亲本菌株带入后代，该亲本菌株含有来自花酵母遗传组的渐渗基因。鉴定出的致病基因在功能上与定量蛋白质组变异相关，这可以解释葡萄酒酵母和花酵母在三羧酸循环（TCA）、乙醛酸分流以及质子和氧化还原辅因子稳态方面不同的代谢特征。总体而言，这项工作导致鉴定出了在葡萄酒生态位中花酵母和葡萄酒酵母适应性分化标志的遗传因素。这些结果还表明，源自种内杂交事件的渐渗促进了葡萄酒菌株中观察到的碳代谢表型变异性。
