Sipiczki Matthias
Department of Genetics and Applied Microbiology, University of Debrecen Debrecen, Hungary.
Front Microbiol. 2016 Feb 29;7:212. doi: 10.3389/fmicb.2016.00212. eCollection 2016.
The conversion of grape must into wine involves the development and succession of yeast populations differing in species composition. The initial population is formed by vineyard strains which are washed into the must from the crushed grapes and then completed with yeasts coming from the cellar environment. As the origin and natural habitat of the vineyard yeasts are not fully understood, this study addresses the possibility, that grape yeasts can be preserved in berries left behind on vines at harvest until the spring of the next year. These berries become mummified during the winter on the vines. To investigate whether yeasts can survive in these overwintering grapes, mummified berries were collected in 16 localities in the Tokaj wine region (Hungary-Slovakia) in early March. The collected berries were rehydrated to recover viable yeasts by plating samples onto agar plates. For the detection of minority species which would not be detected by direct plating, an enrichment step repressing the propagation of alcohol-sensitive yeasts was also included in the process. The morphological, physiological, and molecular analysis identified 13 basidiomycetous and 23 ascomycetous species including fermentative yeasts of wine-making relevance among the 3879 isolates. The presence of viable strains of these species demonstrates that the grapes mummified on the vine can serve as a safe reservoir of yeasts, and may contribute to the maintenance of grape-colonizing yeast populations in the vineyard over years, parallel with other vectors and habitats. All basidiomycetous species were known phylloplane yeasts. Three Hanseniaspora species and pigmented Metschnikowia strains were the most frequent ascomycetes. Other fermentative yeasts of wine-making relevance were detected only in the enrichment cultures. Saccharomyces (S. paradoxus, S. cerevisiae, and S. uvarum) were recovered from 13% of the samples. No Candida zemplinina was found. The isolates with Aureobasidium morphology turned out to belong to Aureobasidium subglaciale, Kabatiella microsticta, or Columnosphaeria fagi. The ascomyceteous isolates grew at high concentrations of sugars with Wickerhamomyces anomalus being the most tolerant species. Complex interactions including antagonism (growth inhibition, contact inhibition, competition for nutrients) and synergism (crossfeeding) among the isolates and with Botrytis cinerea shape the composition of the overwintering communities.
葡萄汁转化为葡萄酒的过程涉及酵母菌群的发展和演替，这些菌群在物种组成上存在差异。初始菌群由葡萄园菌株构成，它们从破碎的葡萄中被冲洗到葡萄汁中，随后酒窖环境中的酵母也加入进来。由于葡萄园酵母的起源和自然栖息地尚未完全明确，本研究探讨了葡萄酵母能否在收获时留在葡萄藤上的浆果中保存至次年春天的可能性。这些浆果在冬季会在葡萄藤上干枯成木乃伊状。为了研究酵母能否在这些越冬葡萄中存活，3月初在托卡伊葡萄酒产区（匈牙利 - 斯洛伐克）的16个地点收集了干枯成木乃伊状的浆果。通过将样本接种到琼脂平板上使收集的浆果复水，以恢复有活力的酵母。为了检测直接平板接种无法检测到的少数物种，该过程还包括一个抑制酒精敏感酵母繁殖的富集步骤。形态学、生理学和分子分析在3879个分离株中鉴定出13种担子菌和23种子囊菌，其中包括与酿酒相关的发酵酵母。这些物种中有活力菌株的存在表明，在葡萄藤上干枯成木乃伊状的葡萄可作为酵母的安全储存库，并可能与其他载体和栖息地一起，多年来有助于维持葡萄园中的葡萄定殖酵母菌群。所有担子菌都是已知的叶表面酵母。三种汉逊酵母属物种和有色梅奇酵母菌株是最常见的子囊菌。其他与酿酒相关的发酵酵母仅在富集培养物中被检测到。从13%的样本中分离出了酵母属（奇异酵母、酿酒酵母和葡萄汁酵母）。未发现岑布林念珠菌。形态为 Aureobasidium 的分离株结果表明属于亚冰状 Aureobasidium、微小卡氏腔孢霉或壳针孢属真菌。子囊菌分离株在高糖浓度下生长，异常威克汉姆酵母是最耐受的物种。分离株之间以及与灰葡萄孢之间的复杂相互作用，包括拮抗作用（生长抑制、接触抑制、营养竞争）和协同作用（交叉喂养），塑造了越冬群落的组成。
