古丝绸之路（中国境内）传统发酵食品酿酒酵母种群演化研究

Saccharomyces cerevisiae is the main driving force of traditional food fermentation; Both geographic differentiation and human activities drive the global evolution of S.cerevisiae, but its domestication origin is keeping unknown as a academic dispute. The Silk Road combined diverse geographical features and diversity civilization is an ideal model to research the domestication of S.cerevisiae population and maybe only way to solve the argument. Our previously research has primarily proven S.cerevisiae population in Xinjiang has rich diversity with unique genotypic - phenotypic groups and potential new lineage, and its evolutionary route is likely to be coupled the Silk Road. This project intends to collect S.cerevisae strains associated with traditional fermented foods along the Silk Road in China. By assessing the growth and metabolic properties and genetic types by Simple Sequence Repeats of collected strains, S.cerevisiae representative strains with typical phenotypic characteristics and different genetic types are screened, and then the genome of these selected strains are sequenced to analyze S.cerevisaie population structure and typical genotype- environment - phenotype features, and, to reveal their history of domestication and evolution comparing to reference strains from the world, and combining information from geography, ecology, evolution of traditional food , culture background along Silk Road, with the aims to provide newly critical proof to solve the argument on S.cerevisiae domestication origin, and to reserve high quality strains for industrial production and scientific research, and to lay a good scientific foundation to drive a new development of traditional fermented food along the Silk Road.

酿酒酵母是食品发酵的主要驱动力；地理分化与人类活动双重作用推动酿酒酵母的全球演化，但其起源于中国还是地中海，东西方存有学术之争；连接东西文明，集多样地域特征与人文特征为一体的古丝绸之路，是研究酿酒酵母驯化的理想的自然模型和解决酿酒酵母起源之争的可能的必经途径。本课题组初步探明新疆葡萄酒酿酒酵母种群多样分化，具有丰富的基因-表型特征及潜在新谱系，其传播途径可能与古丝路文明传播耦合。由此本项目拟收集古丝路（中国境内）的传统发酵食品酿酒酵母，对其群体生长特性和代谢特性进行评估及SSR分型，挑选典型表型-基因型代表株进行基因组重测序，分析酿酒酵母群体结构及表型-环境-基因型特征，结合地理生态、传统发酵食品演变历史、人文背景等特征信息，揭示沿丝路带酿酒酵母种群演化规律，为解决酿酒酵母起源之争提供关键性理论支撑，为传统发酵食品的改进和科学研究贮备用菌资源，助力古丝路带上传统发酵食品的传承与发扬。

目前由国内外专家一致认为酿酒酵母起源地包括中国东南及台湾的远东地区，但起源中国的酿酒酵母在世界范围内的传播途径与驯化模式仍然不清。为此，本项目通过古丝绸之路（中国境内）的馒头和葡萄酒酿酒酵母进行群体演化分析，得到：沿古丝绸之路酿酒酵母极其丰富多样，具有地方分化谱系，其中葡萄酒酿酒酵母表现出CHN-Ⅷ、CHN-VI/VI野生谱系、与驯化型地方谱系共存，馒头菌谱系表现出驯化型的Mantou3、Mantou2、Mantou6、 Baijiu/Huangjiu等。本项目证明古丝绸之路是酿酒酵母从中国传向世界的重要的传播途径。古丝绸之路葡萄酒酿酒酵母谱系、馒头谱系分布与白逢彦团队报道一致，即：来自于果园的野生谱系CHN-Ⅷ是不同驯化型葡萄酒酿酒酵母谱系的近祖先菌，而馒头菌均为驯化型谱系，没有明显的地方谱系；CHN-VI/VII谱系为各馒头谱系和大部分葡萄酒酿酒谱系和共享祖先，早于CHN-Ⅷ谱系。这在较窄时空及基质中（即在古丝绸之路的葡萄与酵头生态基质）证明白逢彦团队的驯化型酿酒酵母存在液态发酵型与固态发酵型两种，我们进一步创新提出固液驯化型不同是源于断代式驯化和传代式驯化的不同模式。断代式驯化由季节性将自然界的酵母进行驯化，传代式驯化为酵头、曲等传代培养方式驯化。葡萄酒酿酒酵母驯化模式为断代式驯化，具体为季节性果园+酒厂（果园驯化功能可能超过酒厂）驯化；馒头菌驯化模式是酵头的传代培养。最早野生型祖先菌可能经过两个阶段演化为各种不同驯化类型，即人类有意饮用水果自然发酵酒的过度阶段和人工控制环境中的有意酿制的驯化阶段。其中人工干预环境中（例如果园）的野生谱系CHN-Ⅷ、CHN-VI/VII可能是驯化谱系的过度阶段。这种通过果园+酒厂的季节性驯化模式和两段驯化进程的理论，需要进一步深入探讨，但葡萄酒的自然发酵微生物的导向性控制可能要提前在葡萄园，这为葡萄酒酒回归自然生态发酵或获得优良菌株提供了新的方向性参考。也为类似酒精发酵产品（例如乳酒、啤酒等回归自然生态发酵或获得优良菌株提供相近的参考。