Department of Horticulture, Washington State University, Pullman, WA, USA.
Department of Viticulture and Enology, Irrigated Agriculture Research and Extension Center, Washington State University, Prosser, WA, USA.
Sci Rep. 2023 Jun 19;13(1):9907. doi: 10.1038/s41598-023-36160-x.
Recurring heat and drought episodes present challenges to the sustainability of grape production worldwide. We investigated the impacts of heat and drought stress on transcriptomic and metabolic responses of berries from two wine grape varieties. Cabernet Sauvignon and Riesling grapevines were subjected to one of four treatments during early fruit ripening: (1) drought stress only, (2) heat stress only, (3) simultaneous drought and heat stress, (4) no drought or heat stress (control). Berry metabolites, especially organic acids, were analyzed, and time-course transcriptome analysis was performed on samples before, during, and after the stress episode. Both alone and in conjunction with water stress, heat stress had a much more significant impact on berry organic acid content, pH, and titratable acidity than water stress. This observation contrasts with previous reports for leaves, which responded more strongly to water stress, indicating that grape berries display a distinct, organ-specific response to environmental stresses. Consistent with the metabolic changes, the global transcriptomic analysis revealed that heat stress had a more significant impact on gene expression in grape berries than water stress in both varieties. The differentially expressed genes were those associated with the tricarboxylic acid cycle and glyoxylate cycle, mitochondrial electron transport and alternative respiration, glycolysis and gluconeogenesis, carbohydrate allocation, ascorbate metabolism, and abiotic stress signaling pathways. Knowledge regarding how environmental stresses, alone and in combination, impact the berry metabolism of different grape varieties will form the basis for developing recommendations for climate change mitigation strategies and genetic improvement.
反复出现的高温和干旱事件给全球葡萄生产的可持续性带来了挑战。我们研究了高温和干旱胁迫对两种酿酒葡萄品种浆果的转录组和代谢响应的影响。在果实早期成熟期间，对赤霞珠和雷司令葡萄藤进行了四种处理之一：（1）仅干旱胁迫，（2）仅热胁迫，（3）干旱和热胁迫同时发生，（4）无干旱或热胁迫（对照）。分析了浆果代谢物，特别是有机酸，并在胁迫发生前后对样品进行了时间过程转录组分析。单独或与水分胁迫结合，热胁迫对浆果有机酸含量、pH 值和可滴定酸度的影响比水分胁迫大得多。这一观察结果与先前关于叶片的报告形成对比，叶片对水分胁迫的反应更为强烈，表明葡萄浆果对环境胁迫表现出独特的器官特异性反应。与代谢变化一致，全局转录组分析表明，在两种品种中，热胁迫对葡萄浆果基因表达的影响比水分胁迫更为显著。差异表达的基因与三羧酸循环和乙醛酸循环、线粒体电子传递和替代呼吸、糖酵解和糖异生、碳水化合物分配、抗坏血酸代谢和非生物胁迫信号通路有关。了解环境胁迫单独和组合如何影响不同葡萄品种的浆果代谢，将为制定气候变化缓解策略和遗传改良建议奠定基础。
