Fei Liu¹, Qi Liu², Ju‐Hua Wu, Zong‐Qi Wang, Yuan‐Jun Geng, Juan Li, Yan Zhang, Sha Li

Abstract

Stomatal movement is critical for water transpiration, gas exchange, and responsesto biotic stresses. Abscisic acid (ABA) induces stomatal closure to prevent water lossduring drought. We report that Arabidopsis CIPK8 negatively regulates ABA‐mediated stomatal closure and drought tolerance.CIPK8is highly enriched in guardcells and transcriptionally induced by ABA. Functional loss ofCIPK8results inhypersensitive stomatal closure to ABA and enhanced drought tolerance. Guard cell‐specific downregulation ofCIPK8mimics the phenotype ofcipk8whereas guard cell‐specific expression of a constitutive active CIPK8 (CIPK8CA) has an opposite effect,suggesting a cell autonomous activity of CIPK8. CIPK8 physically interacts withCBL1 and CBL9. Functional loss ofCBL1andCBL9mimics ABA‐hypersensitivestomatal closure ofcipk8whereas abolishes the effect ofCIPK8CA, indicating thatCIPK8 and CBL1/CBL9 form a genetic module in ABA‐responsive stomatalmovement.SlCIPK7, the functional homolog ofCIPK8in tomato (Solanumlycopersicum), plays a similar role in ABA‐responsive stomatal movement. Genomicediting ofSlCIPK7results in more drought‐tolerant tomato, making it a goodcandidate for germplasm improvement.

Paper Linkage:https://onlinelibrary.wiley.com/doi/epdf/10.1111/pce.14887