Heat shock proteins (HSPs) and abscisic acid (ABA) play important roles in plant heat responses but have not been extensively studied in pea (Pisum sativum L.), whose heat susceptibility is well known. In this study, four pea varieties varying in heat tolerance based on field trials were evaluated. Plants were heat stressed for 3, 6, 12, or 24 h at 38 °C before pollination. Anther and stipule RNA from the same flowering node were sampled for transcriptional profiling of PsHSP18.1 and PsHSP71.2. Additional stipules were sampled for the quantification of ABA concentration and its five key catabolites from the four major ABA catabolic pathways by ultra-high performance liquid chromatography–selected reaction monitoring mass spectrometry (UHPLC-SRM/MS). The transcription of both HSP genes was upregulated because of heat stress (HS). In stipules, the upregulation was greatest at 3 h HS, whereas in anthers, the induced transcription was similar among different hours of HS. Likewise, more ABA accumulated in the ABA metabolism pool because of HS, and the ABA response started rapidly after 3 h of treatment. Heat-tolerant varieties had a higher ABA synthesis and turnover rate at 3 h HS than their respective heat-susceptible counterparts. This study provides new insights into different heat tolerance among Canadian pea varieties regarding HSP and ABA hormone regulation.

中文翻译：

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豌豆品种热胁迫诱导脱落酸和热休克蛋白反应的比较分析

热休克蛋白 (HSP) 和脱落酸 (ABA) 在植物热响应中起着重要作用，但尚未在豌豆 ( Pisum sativum L.) 中进行广泛研究，豌豆的热敏感性是众所周知的。在这项研究中，根据田间试验评估了四种耐热性不同的豌豆品种。在授粉前，植物在 38°C 下热应激 3、6、12 或 24 小时。对来自同一开花节点的花药和托叶 RNA 进行取样，用于PsHSP18.1和PsHSP71.2的转录分析. 通过超高效液相色谱-选择反应监测质谱法 (UHPLC-SRM/MS)，对额外的托叶进行取样，以定量 ABA 浓度及其来自四种主要 ABA 分解代谢途径的五种关键分解代谢物。由于热应激 (HS)，两种 HSP 基因的转录都被上调。在托叶中，上调在 3 小时 HS 时最大，而在花药中，诱导的转录在 HS 的不同小时之间是相似的。同样，由于 HS，更多的 ABA 在 ABA 代谢池中积累，并且 ABA 反应在处理 3 小时后迅速开始。耐热品种在 3 小时 HS 时的 ABA 合成和周转率高于其各自的热敏品种。