Grape heat and water stress RNAseq

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.

频繁发生的气温与干旱事件对全球葡萄生产的可持续性构成了挑战。本研究旨在探讨气温与干旱胁迫对两种酿酒葡萄品种浆果转录组及代谢响应的影响。在果实早期成熟阶段，卡本内苏维翁和雷司令葡萄植株分别接受了四种处理之一：1）仅干旱胁迫，2）仅热胁迫，3）同时干旱与热胁迫，4）无干旱或热胁迫（对照组）。对浆果代谢物，尤其是有机酸进行了分析，并对胁迫事件前、中、后的样品进行了时间序列转录组分析。与水分胁迫相比，热胁迫单独或与水分胁迫相结合，对浆果有机酸含量、pH值和滴定酸度的影响更为显著。这一观察结果与之前关于叶片的研究报告形成对比，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、器官特异性的反应。与代谢变化一致，全局转录组分析揭示了在两种品种中，热胁迫对基因表达的影响均大于水分胁迫。差异表达基因涉及三羧酸循环和乙醛酸循环、线粒体电子传递和替代呼吸、糖酵解和葡萄糖生成、碳水化合物分配、抗坏血酸代谢以及非生物胁迫信号通路。了解环境胁迫，无论是单独还是联合作用，如何影响不同葡萄品种的浆果代谢，将成为制定气候变化缓解策略和遗传改良建议的基础。