Arabidopsis thaliana WRKY25 Transcription Factor Mediates Oxidative Stress Tolerance and Regulates Senescence in a Redox-Dependent Manner
Arabidopsis thaliana WRKY25 Transcription Factor Mediates Oxidative Stress Tolerance and Regulates Senescence in a Redox-Dependent Manner
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DOI：
10.3389/fpls.2019.01734
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发表时间：
2020-01-23
影响因子：
5.6
通讯作者：
Zentgraf, Ulrike
中科院分区：
文献类型：
--
作者：
Doll, Jasmin;Muth, Maren;Zentgraf, Ulrike
衰老是植物生命发育的最后一步，伴随着基因表达的巨大变化，这意味着转录调控因子的强烈参与。在过去的十年中，WRKY53转录因子被发现是叶片衰老复杂调控网络的中心节点，并在表达、活性和蛋白质稳定性的多层控制中起着重要作用。在这里，我们发现WRKY25是WRKY53表达的氧化还原敏感上游调控因子。在非氧化条件下，WRKY25与WRKY53启动子中特定的W-box结合，并在拟南芥原生质体瞬时表达系统中作为WRKY53表达的正调节因子，而氧化条件则抑制WRKY25的作用。然而，过表达WRKY25并不会加速拟南芥植株的衰老，反而会延长其寿命，而敲除该基因则会导致相反的表型，这表明WRKY25在WRKY衰老调控亚网络中具有更复杂的调控功能。此外，WRKY25过表达介导了更高的氧化应激耐受性，并且与野生型植物相比，WRKY25过表达植物的细胞内H2O2水平较低，而WRKY25突变体的细胞内H2O2水平较高，这表明WRKY25也参与控制细胞内氧化还原条件。WRKY25过表达的突变体清除H2O2的能力较高，而过表达的突变体清除H2O2的能力较低。与WRKY53一样，MEKK1积极影响WRKY25在WRKY53启动子上的激活电位。综上所述，WRKY53、WRKY25、MEKK1和H2O2在一个复杂的网络中相互作用。由于H2O2信号分子参与了许多应激反应，WRKK25最有可能作为环境信号的整合者参与衰老调控。
Senescence is the last developmental step in plant life and is accompanied by a massive change in gene expression implying a strong participation of transcriptional regulators. In the past decade, the WRKY53 transcription factor was disclosed to be a central node of a complex regulatory network of leaf senescence and to underlie a tight multi-layer control of expression, activity and protein stability. Here, we identify WRKY25 as a redox-sensitive up-stream regulatory factor of WRKY53 expression. Under non-oxidizing conditions, WRKY25 binds to a specific W-box in the WRKY53 promoter and acts as a positive regulator of WRKY53 expression in a transient expression system using Arabidopsis protoplasts, whereas oxidizing conditions dampened the action of WRKY25. However, overexpression of WRKY25 did not accelerate senescence but increased lifespan of Arabidopsis plants, whereas the knock-out of the gene resulted in the opposite phenotype, indicating a more complex regulatory function of WRKY25 within the WRKY subnetwork of senescence regulation. In addition, overexpression of WRKY25 mediated higher tolerance to oxidative stress and the intracellular H2O2 level is lower in WRKY25 overexpressing plants and higher in wrky25 mutants compared to wildtype plants suggesting that WRKY25 is also involved in controlling intracellular redox conditions. Consistently, WRKY25 overexpressers had higher and wrky mutants lower H2O2 scavenging capacity. Like already shown for WRKY53, MEKK1 positively influenced the activation potential of WRKY25 on the WRKY53 promoter. Taken together, WRKY53, WRKY25, MEKK1 and H2O2 interplay with each other in a complex network. As H2O2 signaling molecule participates in many stress responses, WRKK25 acts most likely as integrators of environmental signals into senescence regulation.