Evolutionary Trade-off Between Stomatal Defense and Gas Exchange in Brassicaceae

Stomatal opening is crucial for gas exchange, but it unavoidably offers invasion by pathogens. In response, plants close stomata to prevent pathogen entry, while the bacterial pathogenPseudomonas syringaepv. tomato DC3000 (Pto) produces coronatine (COR), a jasmonate (JA) mimic, to counteract this plant response. Here, we demonstrate that by COR,PtoexploitsCYP707A1activation inArabidopsis thaliana, encoding an enzyme that degrades abscisic acid, essential for stomatal closure. Notably, COR-induction ofCYP707A1is absent in other Brassicaceae species, such asCapsella rubellaandEutrema salsugineum, rendering them resistant toPtoinvasion. In contrast, inA. thaliana,CYP707A1enables rapid stomatal opening at dawn in a JA-dependent manner, enhancing gas exchange and chlorophyll content, unlikeC. rubellaandE. salsugineum. Promoter-swap experiments confirm that the regulatory region ofCYP707A1underlies these evolutionary diversifications. Together, our study presents a mechanism underlying an evolutionary trade-off between stomatal defense and gas exchange.