The abscisic acid (ABA) receptor PYR/PYL/RCAR, located upstream of the ABA signaling pathway, recognizes ABA signals and initiates the primary process of signal transduction. In our previous study, we found that the PYL4 gene in tomato plants was significantly upregulated after exogenous treatment with the hormone ABA. The present study used virus-induced gene silencing (VIGS) to further elucidate the role of the PYL4 gene in response to drought in tomato (Solanum lycopersicum) plants. Under the drought treatment, the SlPYL4-silenced plants wilted faster than the control plants did. Physiological indicators showed that the total reactive oxygen species (ROS) content and superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities of the SlPYL4-silenced plants were lower than those of the control plants after 3 and 6 h of drought stress treatment. After 3 h of drought treatment, hydrogen peroxide (H₂O₂) and superoxide anion (O₂^−.) accumulated much more in the leaves of the SlPYL4-silenced plants than in the leaves of the control plants. These results indicated that PYL4 plays a positive role in drought tolerance in tomato plants. Our results also suggest that SlPYL4 is located upstream of the ABA pathway to regulate the expression of PP2C, SnRK, and AREB/ABF genes.

脱落酸 (ABA) 受体 PYR/PYL/RCAR 位于 ABA 信号通路的上游，识别 ABA 信号并启动信号转导的初级过程。在我们之前的研究中，我们发现用激素 ABA 进行外源处理后，番茄植株中的PYL4基因显着上调。本研究使用病毒诱导的基因沉默 (VIGS) 来进一步阐明PYL4基因在响应番茄 ( Solanum lycopersicum ) 植物中的干旱中的作用。在干旱处理下，SlPYL4- 沉默的植物比对照植物枯萎得更快。生理指标表明，SlPYL4沉默植株的总活性氧 (ROS) 含量和超氧化物歧化酶 (SOD)、过氧化物酶 (POD) 和过氧化氢酶 (CAT) 活性在 3 小时和 6 小时后低于对照植株。干旱胁迫处理。干旱处理 3 小时后，过氧化氢 (H ₂ O ₂ ) 和超氧阴离子 (O ₂ ^-. ) 在SlPYL4沉默植物的叶子中比在对照植物的叶子中积累的多得多。这些结果表明PYL4在番茄植物的耐旱性中起积极作用。我们的结果还表明SlPYL4位于 ABA 通路的上游以调节PP2C、SnRK和AREB/ABF基因的表达。