Stomatal pores in the plant epidermis open and close to regulate gas exchange between leaves and the atmosphere. Upon light stimulation, the plasma membrane (PM) H⁺-ATPase is phosphorylated and activated via an intracellular signal transduction pathway in stomatal guard cells, providing a primary driving force for the opening movement. To uncover and manipulate this stomatal opening pathway, we screened a chemical library and identified benzyl isothiocyanate (BITC), a Brassicales-specific metabolite, as a potent stomatal-opening inhibitor that suppresses PM H⁺-ATPase phosphorylation. We further developed BITC derivatives with multiple isothiocyanate groups (multi-ITCs), which demonstrate inhibitory activity on stomatal opening up to 66 times stronger, as well as a longer duration of the effect and negligible toxicity. The multi-ITC treatment inhibits plant leaf wilting in both short (1.5 h) and long-term (24 h) periods. Our research elucidates the biological function of BITC and its use as an agrochemical that confers drought tolerance on plants by suppressing stomatal opening.

植物表皮中的气孔打开和关闭以调节叶片与大气之间的气体交换。在光刺激下，质膜 (PM) H ⁺ -ATP 酶通过气孔保卫细胞中的细胞内信号转导通路被磷酸化和激活，为开放运动提供主要驱动力。为了发现和操纵这种气孔开放途径，我们筛选了一个化学库并确定了异硫氰酸苄酯 (BITC)，这是一种芸苔目特异性代谢物，是一种有效的气孔开放抑制剂，可抑制 PM H ⁺-ATP酶磷酸化。我们进一步开发了具有多个异硫氰酸酯基团 (multi-ITC) 的 BITC 衍生物，其对气孔开放的抑制活性高达 66 倍，而且效果持续时间更长，毒性可忽略不计。多 ITC 处理在短期（1.5 小时）和长期（24 小时）期间抑制植物叶片枯萎。我们的研究阐明了 BITC 的生物学功能及其作为农用化学品的用途，通过抑制气孔开放赋予植物耐旱性。