番茄SlWRKY6-SlABI5模块参与调节叶片衰老OA

[Objective]Leaf senescence is the final stage of plant growth and development,involving multiple physiological pro-cesses such as chlorophyll degradation and nutrient redistribution,which significantly affect crop yield and quality.Previous studies have shown that the tomato transcription factor SlWRKY6 is able to integrate hormone and reactive oxygen species(ROS)signals to positively regulate leaf senescence.Abscisic acid(ABA)is a key hormone inducing senescence,and AB-SCISIC ACID INSENSITIVE 5(ABI5),a core transcription factor in its signaling pathway,plays an important role in the se-nescence process.However,whether SlWRKY6 mediates ABA signaling by regulating SlABI5 is still unclear.This study aimed to clarify whether SlWRKY6 affects tomato leaf senescence by regulating SlABI5,so as to complement its molecular reg-ulatory mechanism.[Method]Phenotypes were observed through detached senescence experiment assay,and chlorophyll and carotenoid contents were measured using spectrophotometry.Electrophoretic mobility shift assay(EMSA)and dual-luciferase reporter assay(dual-LUC)were performed to verify the regulatory effect of SlWRKY6 on the promoter activity of SlABI5.RT-qPCR technology was utilized to detect the expression levels of SlABI5 in WT,SlWRKY6OX,and slwrky6-cr materi-als.[Result](1)The SlWRKY6OX lines showed significantly accelerated leaf senescence and significantly reduced chlorophyll content,while the slwrky6-cr mutants showed delayed senescence and increased chlorophyll content,indicating that Sl-WRKY6 promoted leaf senescence.(2)Subcellular localization analysis revealed that SlWRKY6 was localized in the nucleus.(3)EMSA results demonstrated that SlWRKY6 could specifically bind to the W-box element in the SlABI5 promoter.(4)RT-qPCR analysis showed that SlABI5 expression was significantly upregulated in SlWRKY6OX and downregulated in sl-wrky6-cr,indicating that SlWRKY6 positively regulated the expression of SlABI5.(5)The dual-LUC experiment further confirmed that SlWRKY6 significantly activates the promoter activity of SlABI5.[Conclusion]SlWRKY6 not only could di-rectly regulate senescence-associated genes but also promoted tomato leaf senescence by activating SlABI5 expression and me-diating the ABA signaling pathway.This study revealed the regulatory role of the SlWRKY6-SlABI5 module in tomato leaf se-nescence and provided a theoretical basis for delaying crop senescence and improving yield and quality through molecular biolo-gy approaches.