SCAB1 coordinates sequential Ca^(2+) and ABA signals during osmotic stress induced stomatal closure in Arabidopsis  

作　　者：Tianren Zhang Li Bai Yan Guo 

机构地区：[1]State Key Laboratory of Plant Environmental Resilience,College of Biological Sciences,China Agricultural University,Beijing 100193,China

出　　处：《Science China(Life Sciences)》2024年第1期1-18,共18页中国科学（生命科学英文版）

基　　金：This work was supported by the National Natural Science Foundation of China(31921001).

摘　　要：Hyperosmotic stress caused by drought is a detrimental threat to plant growth and agricultural productivity due to limited water availability.Stomata are gateways of transpiration and gas exchange,the swift adjustment of stomatal aperture has a strong influence on plant drought resistance.Despite intensive investigations of stomatal closure during drought stress in past decades,little is known about how sequential signals are integrated during complete processes.Here,we discovered that the rapid Ca^(2+) signaling and subsequent abscisic acid(ABA)signaling contribute to the kinetics of both F-actin reorganizations and stomatal closure in Arabidopsis thaliana,while STOMATAL CLOSURE-RELATED ACTIN BINDING PROTEIN1(SCAB1)is the molecular switch for this entire process.During the early stage of osmotic shock responses,swift elevated calcium signaling promotes SCAB1 phosphorylation through calcium sensors CALCIUM DEPENDENT PROTEIN KINASE3(CPK3)and CPK6.The phosphorylation restrained the microfilament binding affinity of SCAB1,which bring about the Factin disassembly and stomatal closure initiation.As the osmotic stress signal continued,both the kinase activity of CPK3 and the phosphorylation level of SCAB1 attenuated significantly.We further found that ABA signaling is indispensable for these attenuations,which presumably contributed to the actin filament reassembly process as well as completion of stomatal closure.Notably,the dynamic changes of SCAB1 phosphorylation status are crucial for the kinetics of stomatal closure.Taken together,our results support a model in which SCAB1 works as a molecular switch,and directs the microfilament rearrangement through integrating the sequentially generated Ca^(2+) and ABA signals during osmotic stress induced stomatal closure.

关 键 词：calcium signal ABA stomatal movement MICROFILAMENTS KINASE 

分 类 号：Q945.78[生物学—植物学]