Regulation Of The WD-repeat/bHLH/MYB Complex By Gibberellin And Jasmonate

The phytohormones jasmonate(JA)and gibberellin(GA)regulate various aspects of plant development,growth and defense.Previous studies showed that both JA-ZIM domain(JAZ)proteins in JA pathway and DELLA repressors in GA pathway interact with and repress the WD-repeat/bHLH/MYB transcriptional complex to inhibit trichome initiation,and JA and GA respectively induce JAZs and DELLAs degradation to synergistically enhance trichome formation.In this study,we showed that the DELLA protein RGA and JAZ1 competitively bind to ENHANCER OF GLABRA3(EGL3),a bHLH component of the WDrepeat/bHLH/MYB complex by a pull-down assay.Our quantitative real-time PCR and weatern-blot analysis showed GA and JA differently affect the expression and protein stability of the components of the WD-repeat/bHLH/MYB complex,and EGL3 and GL3 repress the expression of JAZ genes as a feedback.The novel findings help to understand the mechanism of the WD-repeat/bHLH/MYB complex in GA/JA regulated trichome formation.