Sica Jacopo, Bovo Barbara, Nadai Chiara, Carlot Milena, Giacomini Alessio, Corich Viviana
Department of Agronomy Food Natural Resources Animals and Environment (DAFNAE), University of Padova, Viale dell'Università 16, 35020, Legnaro, PD, Italy.
Interdepartmental Centre for Research in Viticulture and Enology (CIRVE), University of Padova, Viale XXVIII Aprile 14, 31015, Conegliano, TV, Italy.
Heliyon. 2024 Jul 20;10(15):e34885. doi: 10.1016/j.heliyon.2024.e34885. eCollection 2024 Aug 15.
The widespread use of copper-based pesticides in winemaking can affect wine fermentation. Therefore, it is crucial to assess the resistance levels of wine strains in enological growth conditions. In the context of winemaking, grape juice is a complex environment capable of chelating copper and is characterized by a distinctly acidic pH. In this work, the effects of copper concentration on the growth of 10 strains, isolated from an enological environment, and one commercial starter were tested in YNB minimal medium and synthetic must, mimicking enological conditions. In minimal medium, resistance to copper varied among yeasts (50-600 μM), revealing the presence of three resistance levels (high, intermediate, and low). Representative strains of the three groups were tested at a pH range from 5.2 to 3.0 at the copper concentration that showed a 20-25 % growth reduction. At pH range 5.2-4.5, a growth reduction was observed, while, conversely, a strain-specific recovery was observed at pH range 3.2-3.0. In synthetic must, the strains showed higher copper resistance levels than in minimal medium (50-4000 μM). In both synthetic must and minimal medium, a significant logarithmic correlation was found between copper resistance and gene copy number. The copy number tended to better explain resistance in minimal medium compared to synthetic must. The results shed light on the role of copy number within an enological environment.
酿酒过程中铜基农药的广泛使用会影响葡萄酒发酵。因此，评估酿酒酵母菌株在酿酒生长条件下的抗性水平至关重要。在酿酒背景下，葡萄汁是一个能够螯合铜的复杂环境，其特点是pH值明显呈酸性。在这项研究中，在模拟酿酒条件的YNB基本培养基和合成葡萄汁中，测试了从酿酒环境中分离出的10株菌株和一种商业发酵剂对铜浓度的反应。在基本培养基中，酵母对铜的抗性各不相同（50 - 600 μM），显示出三种抗性水平（高、中、低）。在导致生长降低20 - 25%的铜浓度下，对这三组的代表性菌株在pH值范围为5.2至3.0的条件下进行了测试。在pH值范围5.2 - 4.5时，观察到生长降低，相反，在pH值范围3.2 - 3.0时，观察到菌株特异性的生长恢复。在合成葡萄汁中，菌株显示出比在基本培养基中更高的铜抗性水平（50 - 4000 μM）。在合成葡萄汁和基本培养基中，均发现铜抗性与基因拷贝数之间存在显著的对数相关性。与合成葡萄汁相比，基因拷贝数在基本培养基中似乎能更好地解释抗性。这些结果揭示了基因拷贝数在酿酒环境中的作用。
