Coronatine orchestrates ABI1 ‐mediated stomatal opening to facilitate bacterial pathogen infection through importin β protein SAD2

作者：Lu Liu, Yanzhi Liu, Xuehan Ji, Xia Zhao, Jun Liu, Ning Xu · 发表于：The Plant Journal · 年份：2024 · DOI：10.1111/tpj.16784 · 被引用次数：13 · 研究领域：Plant-Microbe Interactions and Immunity、Plant Pathogenic Bacteria Studies、Legume Nitrogen Fixing Symbiosis

Stomatal immunity plays an important role during bacterial pathogen invasion. Abscisic acid (ABA) induces plants to close their stomata and halt pathogen invasion, but many bacterial pathogens secrete phytotoxin coronatine (COR) to antagonize ABA signaling and reopen the stomata to promote infection at early stage of invasion. However, the underlining mechanism is not clear. SAD2 is an importin β family protein, and the sad2 mutant shows hypersensitivity to ABA. We discovered ABI1, which negatively regulated ABA signaling and reduced plant sensitivity to ABA, was accumulated in the plant nucleus after COR treatment. This event required SAD2 to import ABI1 to the plant nucleus. Abolition of SAD2 undermined ABI1 accumulation. Our study answers the long-standing question of how bacterial COR antagonizes ABA signaling and reopens plant stomata during pathogen invasion.