The accumulation of cold temperature is an important factor for the release of bud dormancy in grapevine. The stress generated by cold is related to changes in defense hormones such as salicylic acid (SA). To understand the participation of this hormone during grapevine bud dormancy release, in this study, we evaluated the effects of cold accumulation on the endogenous SA content and expression patterns of the synthesis and signaling genes of SA as well as budbreak rates. Buds were subjected to an accumulation of 900 or 600 chilling units (CUs). The budbreak percentage was determined when cold-treated buds were transferred to warm temperatures (25 °C). The percentage of budbreak was closely correlated with the amount of cumulative CUs; the percentage increased gradually with the amount of chilling applied before forcing. The increase in the expression level of the SA biosynthesis gene ( ICS2 ) and the endogenous SA content were quantified in cold-treated buds, and the expression was correlated with the percentage of budbreak. These findings may indicate that in dormant grapevine buds, cold accumulation stimulates the synthesis of SA. In cold-treated buds, the cellular levels of SA led to the expression of the NPR1 and PR1 genes, which was mediated by the transcription factor WRKY70 . In contrast, expression of NPR1 and PR1 in control buds, which maintained a basal level of SA, and expression of ICS2 and WRKY70 were not detected, suggesting that the constitutive expression of NPR1-SA is independent. Taken together, the results of this study suggest a possible involvement of the SA signaling pathway in grapevine bud dormancy release.

中文翻译：

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水杨酸内源性含量及基因表达变化与葡萄芽休眠解除的相关性

低温的积累是葡萄树芽休眠解除的重要因素。寒冷产生的压力与水杨酸 (SA) 等防御激素的变化有关。为了了解这种激素在葡萄树芽休眠释放过程中的参与，在本研究中，我们评估了冷蓄积对内源 SA 含量和 SA 合成和信号基因表达模式以及萌芽率的影响。芽经历了 900 或 600 个冷却单元 (CU) 的累积。当冷处理的芽转移到温暖的温度（25°C）时，确定萌芽百分比。萌芽率与累积CU数密切相关；该百分比随着强制前施加的冷却量而逐渐增加。在冷处理芽中量化SA生物合成基因(ICS2)表达水平和内源SA含量的增加，并且表达与萌芽百分比相关。这些发现可能表明，在休眠的葡萄藤芽中，蓄冷刺激了 SA 的合成。在冷处理的芽中，SA 的细胞水平导致 NPR1 和 PR1 基因的表达，这是由转录因子 WRKY70 介导的。相反，未检测到 NPR1 和 PR1 在维持 SA 基础水平的对照芽中的表达，以及 ICS2 和 WRKY70 的表达，表明 NPR1-SA 的组成型表达是独立的。总之，这项研究的结果表明 SA 信号通路可能参与了葡萄树芽休眠的释放。