Signaling mechanisms and agricultural applications of (Z)-3-Hexenyl Butyrate-mediated stomatal closure

It is well known that plants respond to various stresses by releasing volatile organic compounds (VOCs). Green leaf volatiles (GLVs), which are commonly produced across different plant species after tissue damage, comprise an important group within VOCs. Among them, (Z)-3-hexenyl butyrate (HB) was described as a natural stomatal closure inducer, playing an important role in stomatal immunity, although its mechanism of action is still unknown. Here, through different genetic, pharmacological, and biochemical approaches we uncover that HB perception initiates different defense signaling events such as activation of Ca2+ permeable channels, mitogen-activated protein kinases (MPKs) and production of NADPH oxidase-mediated reactive oxygen species (ROS). Furthermore, HB-mediated stomata closure resulted to be independent of abscisic acid (ABA) biosynthesis and signaling. Additionally, exogenous treatments with this volatile alleviate water stress and improve fruit productivity in tomato plants. HB efficacy was also tested under open field conditions, leading to enhanced resistance against Phytophthora spp. and Pseudomonas syringae infection in potato and tomato plants, respectively. Collectively, our results provide insights into HB signaling transduction pathway, confirming its role in stomatal closure and plant immune system activation, and proposing HB as a new phytoprotector for the sustainable control of biotic and abiotic stresses in agriculture.