GSE99290
Functional analysis of evening complex component LUX in Arabidopsis
Plants trigger leaf senescence to relocate energy and nutrients from aging leaves to developing tissues or storage organs to optimize the growth and reproduction under limited nutrients and energy conditions. Jasmonate signaling is one of the major endogenous hormone signals to induced leaf senescence in Arabidopsis. However, whether circadian clock will gate Jasmonate signaling to induce leaf senescence and the underlying precise mechanism is unclear. Here we find that the Evening Complex (EC) of core oscillator closely regulates leaf senescence. To identify the underlying mechanism of EC regulating leaf senescence, we conducted RNA-sequencing. Transcriptomic data reveals Evening complex extensively involves into JA signal transduction and responses. Moreover, the mutants of ELF3, ELF4 and LUX universly display the accelerated JA-induced leaf senescence phenotype, while their overexpression lines act reversely. In accordance with the transcript levels of JA immediate early induced JA-responsive gene MYC2 are up-regulated in lux mutants. Futhermore we demonstrated LUX can bind to to the promoter of MYC2 in vivo to represses its transcription. In addition, the accelerated JA-induced leaf senescence in mutants of evening complex can be overturned by myc2, myc3 and myc4 mutants redundantly. Collectively, our findings demonstrated the underlying molecular basis for circadian clock gating jasmonate signaling to induce leaf senescence through the module of evening complex to directly repressing MYC2 transcription. This novel established molecular module also refines complicated nodes between circadian clock and jasmonate signal in Arabidopsis. Overall design: We analyzed the transcriptomic profile of Col-0 and lux-6 mutant using 10-day-old seedlings, as evening complex negatively regulates leaf senescence through its transcription repressive activity. Two biological replicates were performed with the tissues harvesting at ZT12, the peak expression time of evening complex components.