Vascular plants have evolved intricate long-distance signaling mechanisms to cope with environmental stress, with reactive oxygen species (ROS) emerging as pivotal systemic signals in plant stress responses. However, the exact role of ROS as root-to-shoot signals in the drought response has not been determined. In this study, we reveal that compared with wild-type plants, () mutants exhibit enhanced drought resistance concomitant with elevated transcript levels and ABA contents in leaves as well as increased hydrogen peroxide (HO) levels in roots and leaves. Grafting experiments distinctly illustrate that drought resistance can be conferred by the rootstock regardless of the scion genotype, indicating that long-distance signals originating from roots promote an increase in ABA levels in leaves. Intriguingly, the drought resistance conferred by the mutant rootstock is weakened by the -overexpressing scion, suggesting that HO may be involved in long-distance signaling. Moreover, the results of comparative transcriptome and proteome analyses support the drought resistance phenotype of the mutant. Taken together, our findings substantiate the notion that root-derived long-distance signals trigger ABA synthesis in leaves and enhance drought resistance, providing new evidence for root-to-shoot long-distance signaling in the drought response of plants.

中文翻译：

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根源长距离信号触发脱落酸（ABA）合成并增强拟南芥的抗旱性

维管植物已经进化出复杂的长距离信号机制来应对环境胁迫，其中活性氧（ROS）成为植物胁迫反应中关键的系统信号。然而，ROS 作为根-茎信号在干旱反应中的确切作用尚未确定。在这项研究中，我们发现，与野生型植物相比，()突变体表现出增强的抗旱性，同时叶子中转录水平和ABA含量升高，以及根和叶子中过氧化氢(H2O)水平升高。嫁接实验清楚地表明，无论接穗基因型如何，砧木都可以赋予抗旱性，这表明源自根部的长距离信号促进了叶片中 ABA 水平的增加。有趣的是，突变砧木赋予的抗旱性被过度表达的接穗削弱，这表明 H2O 可能参与长距离信号传导。此外，比较转录组和蛋白质组分析的结果支持突变体的抗旱表型。综上所述，我们的研究结果证实了根源长距离信号触发叶片中 ABA 合成并增强抗旱性的观点，为植物干旱响应中根-芽长距离信号传导提供了新证据。