Plants have developed sophisticated mechanisms to survive in dynamic environments. Plants can communicate via volatile organic compounds (VOCs) to warn neighboring plants of threats. In most cases, VOCs act as positive regulators of plant defense. However, the communication and role of volatiles in response to drought stress are poorly understood. Here, we showed that tea plants release numerous VOCs. Among them, methyl salicylate (MeSA), benzyl alcohol, and phenethyl alcohol markedly increased under drought stress. Interestingly, further experiments revealed that drought-induced MeSA lowered the abscisic acid (ABA) content in neighboring plants by reducing 9-cis-epoxycarotenoid dioxygenase (NCED) gene expression, resulting in inhibition of stomatal closure and ultimately decreasing early drought tolerance in neighboring plants. Exogenous application of ABA reduced the wilting of tea plants caused by MeSA exposure. Exposure of Nicotiana benthamiana to MeSA also led to severe wilting, indicating that the ability of drought-induced MeSA to reduce early drought tolerance in neighboring plants may be conserved in other plant species. Taken together, these results provide evidence that drought-induced volatiles can reduce early drought tolerance in neighboring plants and lay a novel theoretical foundation for optimizing plant density and spacing.

中文翻译：

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由邻近茶树发出的挥发性信号引起的早期干旱响应的放大

植物已经发展出复杂的机制来在动态环境中生存。植物可以通过挥发性有机化合物 (VOC) 进行交流，以警告邻近植物受到威胁。在大多数情况下，VOCs 作为植物防御的积极调节剂。然而，人们对挥发物在应对干旱胁迫中的传播和作用知之甚少。在这里，我们展示了茶树释放大量 VOC。其中，水杨酸甲酯（MeSA）、苯甲醇和苯乙醇在干旱胁迫下显着增加。有趣的是，进一步的实验表明，干旱诱导的 MeSA 通过减少 9-顺-环氧类胡萝卜素双加氧酶降低了邻近植物的脱落酸 (ABA) 含量。NCED) 基因表达，从而抑制气孔关闭并最终降低邻近植物的早期耐旱性。ABA的外源应用减少了由MeSA暴露引起的茶树萎蔫。的接触本氏烟草MeSA 也导致严重的萎蔫，表明干旱诱导的 MeSA 降低邻近植物早期耐旱性的能力可能在其他植物物种中得到保留。总之，这些结果证明干旱诱导的挥发物可以降低邻近植物的早期耐旱性，并为优化植物密度和间距奠定新的理论基础。