WRKY group transcription factors of model plants and major crops are confirmed to play essential roles in stress responses, senescence, secondary metabolism processes and hormone signal transduction. Previous studies have identified 81 HbWRKY genes from Hevea brasiliensis (the Pará rubber tree), but the functions of HbWRKYs in response to abiotic stresses and leaf senescence are unclear. In this study, one novel group IIc WRKY transcription factor named HbWRKY82 was identified and characterized as a stress-associated WRKY in rubber tree. Transient expression and transcriptional activation analyses indicated that HbWRKY82 encoded a nuclear protein and functioned as a transcription activator. The transcription levels of HbWRKY82 were induced by by exogenous Ethrel (ethylene releaser) and abscisic acid (ABA) stimulations, down-regulated in tapping panel dryness rubber trees, and also exhibits significant decrease during the progression of leaf senescence. Overexpression of HbWRKY82 in Arabidopsis improved the tolerance to dehydration and salinity, and decreased the sensitivity to exogenous ABA. Moreover, real-time quantitative PCR analysis demonstrated that HbWRKY82 regulated the transcriptional expression of several stress-responsive genes (DREB1A, ERD10, HKT1, P5CS, RD22, RD29B, SKOR), leaf senescence marker genes (EIN3, WRKY53, NAP), ROS-related genes (RbohD, CSD1, CSD2, FSD3) and hormone signaling genes (EIN3, ABF3, ABF4). Collectively, our findings suggested that HbWRKY82 might function as an important transcriptional regulator in Ethrel -and ABA-mediated leaf senescence and abiotic stress responses, and also be involved in tapping panel dryness, latex flow and regeneration processes of rubber trees via participating in the ET and ROS signaling pathways. This article is protected by copyright. All rights reserved.

中文翻译：

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HbWRKY82，一种来自巴西橡胶树的新型 IIc WRKY 转录因子，与拟南芥的非生物胁迫耐受性和叶片衰老相关

模型植物和主要作物的 WRKY 组转录因子被证实在胁迫反应、衰老、次生代谢过程和激素信号转导中发挥重要作用。先前的研究已经从巴西三叶树（Pará 橡胶树）中鉴定了 81 个 HbWRKY 基因，但 HbWRKYs 在响应非生物胁迫和叶片衰老方面的功能尚不清楚。在这项研究中，一种名为 HbWRKY82 的新型 IIc WRKY 转录因子被鉴定并表征为橡胶树中与压力相关的 WRKY。瞬时表达和转录激活分析表明 HbWRKY82 编码核蛋白并作为转录激活因子发挥作用。HbWRKY82 的转录水平由外源 Ethrel（乙烯释放剂）和脱落酸（ABA）刺激诱导，在敲击面板干燥橡胶树中下调，并且在叶片衰老过程中也表现出显着降低。HbWRKY82 在拟南芥中的过表达提高了对脱水和盐分的耐受性，并降低了对外源 ABA 的敏感性。此外，实时定量 PCR 分析表明，HbWRKY82 调节几种胁迫响应基因（DREB1A、ERD10、HKT1、P5CS、RD22、RD29B、SKOR）、叶片衰老标记基因（EIN3、WRKY53、NAP）、ROS 的转录表达相关基因（RbohD、CSD1、CSD2、FSD3）和激素信号基因（EIN3、ABF3、ABF4）。总的来说，我们的研究结果表明 HbWRKY82 可能在 Ethrel 和 ABA 介导的叶片衰老和非生物胁迫反应中作为重要的转录调节因子，并且还参与敲击面板干燥，通过参与 ET 和 ROS 信号通路来研究橡胶树的乳胶流动和再生过程。本文受版权保护。版权所有。