Table_7_Characterization of Sub-Regional Variation in Saccharomyces Populations and Grape Phenolic Composition in Pinot Noir Vineyards of a Canadian Wine Region.DOCX

Wine is a product of grape juice fermentation by yeast. Terroir is a term that encompasses all environmental factors and interactions at a specific geographical site, resulting in the development of regional-specific microbial strains and grape metabolites. In this study we determine the distribution of vineyard-associated wine yeast strains and characterize the flavonoid profile of Pinot Noir grapes among 3 sub-regions in the Okanagan Valley (OV), a major wine region in British Columbia, Canada. Pinot Noir grape samples were collected from 13 vineyards among 3 sub-regions of the OV, namely Kelowna (KE), Naramata-Penticton (NP) and Oliver-Osoyoos (OO), within a week prior to the winery harvesting date in 2016 and 2017. A total of 156 spontaneous Pinot Noir fermentations were conducted and vineyard-associated Saccharomyces strains were isolated from fermentations that reached two-thirds sugar depletion. Using microsatellite genotyping, we identified 103 Saccharomyces cerevisiae strains and 9 Saccharomyces uvarum strains. We also identified Saccharomyces paradoxus in one vineyard using ITS sequencing. We developed a microsatellite database of 160 commercial S. cerevisiae strains to determine the identity of the isolated strains and we include the database herein. Commercial strains were widely distributed across the three sub-regions. Forty-two of our 103 S. cerevisiae strains were equivalent or highly similar to commercial strains whereas the remaining 61 were considered as ‘unknown’ strains. Two S. uvarum strains were previously isolated in other OV studies and none matched the S. uvarum commercial strain BMV58. S. cerevisiae population structure was driven by sub-region, although S. cerevisiae populations did not differ significantly across vintages. S. uvarum and S. paradoxus were only identified in the 2017 vintage, demonstrating dynamic wine yeast populations between vintages. We found that the flavonoid profile of Pinot Noir grapes from the same 13 vineyards was also affected by sub-regional terroir. The anthocyanin content was lower and the proportion of methoxylated anthocyanins and flavonols was higher in Pinot Noir grapes from OO, the warmer sub-region as compared to KE, the cooler sub-region. Our study demonstrates that both yeast populations and metabolites associated with the Pinot Noir variety have sub-regional variation within a viticultural area.

葡萄酒（Wine）是经酵母发酵葡萄汁所得的产物。风土（Terroir）是涵盖特定地理位点上所有环境因素及其相互作用的术语，这些因素共同促成区域特异性微生物菌株与葡萄代谢物的形成。本研究旨在探究加拿大不列颠哥伦比亚省（British Columbia）核心葡萄酒产区奥卡诺根谷（Okanagan Valley, OV）下属3个亚区域内，与葡萄园相关的葡萄酒酵母菌株分布特征，并解析黑皮诺（Pinot Noir）葡萄的类黄酮谱特征。研究于2016年与2017年酒庄采收前一周内，从奥卡诺根谷的3个亚区域——即基洛纳（Kelowna, KE）、纳拉马塔-彭蒂克顿（Naramata-Penticton, NP）以及奥利弗-奥索尤斯（Oliver-Osoyoos, OO）——的13座葡萄园采集黑皮诺葡萄样本。共计开展156组自发性黑皮诺发酵实验，并从糖耗达三分之二的发酵液中分离得到与葡萄园相关的酿酒酵母（Saccharomyces）菌株。通过微卫星基因分型（microsatellite genotyping），我们共鉴定出103株酿酒酵母（Saccharomyces cerevisiae）与9株真贝酵母（Saccharomyces uvarum，原称卡尔酵母）；此外通过ITS测序（ITS sequencing）在一座葡萄园样本中鉴定出奇异酿酒酵母（Saccharomyces paradoxus）。我们构建了包含160株商业化酿酒酵母菌株的微卫星数据库，用于比对鉴定分离得到的菌株，并将该数据库附于本文中。商业化菌株在3个亚区域中广泛分布。103株酿酒酵母中有42株与商业化菌株同源或高度相似，剩余61株则被归类为‘未知菌株’。两株真贝酵母菌株此前已在奥卡诺根谷的其他研究中被分离，且均未与商业化菌株BMV58匹配。酿酒酵母的种群结构受亚区域驱动，不过不同年份（vintage）间的酿酒酵母种群并无显著差异。真贝酵母与奇异酿酒酵母仅在2017年的样本中被检出，这表明不同年份间葡萄酒酵母种群存在动态变化。我们还发现，来自上述13座葡萄园的黑皮诺葡萄的类黄酮谱同样受亚区域风土特征影响。相较于气候更凉爽的基洛纳亚区域，气候更温暖的奥利弗-奥索尤斯亚区域产出的黑皮诺葡萄中，花青素含量更低，而甲氧基化花青素与黄酮醇的占比更高。本研究证实，与黑皮诺葡萄相关的酵母种群与代谢物，在同一葡萄种植区域内均存在亚区域特异性差异。