Wang Tenghua, Ye Wenxiu, Wang Yin, Zhang Maoxing, Aihara Yusuke, Kinoshita Toshinori
Graduate School of Science, Nagoya University, Nagoya, Japan.
Graduate School of Science, Kyoto University, Kyoto, Japan.
Front Plant Sci. 2021 Sep 10;12:735328. doi: 10.3389/fpls.2021.735328. eCollection 2021.
Stomata in the epidermis of plants play essential roles in the regulation of photosynthesis and transpiration. Stomata open in response to blue light (BL) by phosphorylation-dependent activation of the plasma membrane (PM) H-ATPase in guard cells. Under water stress, the plant hormone abscisic acid (ABA) promotes stomatal closure the ABA-signaling pathway to reduce water loss. We established a chemical screening method to identify compounds that affect stomatal movements in . We performed chemical screening using a protease inhibitor (PI) library of 130 inhibitors to identify inhibitors of stomatal movement. We discovered 17 PIs that inhibited light-induced stomatal opening by more than 50%. Further analysis of the top three inhibitors (PI1, PI2, and PI3; inhibitors of ubiquitin-specific protease 1, membrane type-1 matrix metalloproteinase, and matrix metalloproteinase-2, respectively) revealed that these inhibitors suppressed BL-induced phosphorylation of the PM H-ATPase but had no effect on the activity of phototropins or ABA-dependent responses. The results suggest that these PIs suppress BL-induced stomatal opening at least in part by inhibiting PM H-ATPase activity but not the ABA-signaling pathway. The targets of PI1, PI2, and PI3 were predicted by bioinformatics analyses, which provided insight into factors involved in BL-induced stomatal opening.
植物表皮上的气孔在光合作用和蒸腾作用的调节中起着至关重要的作用。气孔通过保卫细胞中质膜（PM）H-ATP酶的磷酸化依赖性激活对蓝光（BL）作出反应而开放。在水分胁迫下，植物激素脱落酸（ABA）通过ABA信号通路促进气孔关闭以减少水分流失。我们建立了一种化学筛选方法来鉴定影响气孔运动的化合物。我们使用包含130种抑制剂的蛋白酶抑制剂（PI）文库进行化学筛选，以鉴定气孔运动的抑制剂。我们发现17种PI能将光诱导的气孔开放抑制50%以上。对排名前三的抑制剂（PI1、PI2和PI3；分别为泛素特异性蛋白酶1、膜型-1基质金属蛋白酶和基质金属蛋白酶-2的抑制剂）的进一步分析表明，这些抑制剂抑制了BL诱导的PM H-ATP酶的磷酸化，但对向光素的活性或ABA依赖性反应没有影响。结果表明，这些PI至少部分通过抑制PM H-ATP酶活性而非ABA信号通路来抑制BL诱导的气孔开放。通过生物信息学分析预测了PI1、PI2和PI3的靶点，这为深入了解参与BL诱导气孔开放的因素提供了线索。
