FIGURE 1.

A proposed model for interplaying between circadian clock and leaf senescence in Arabidopsis. CCA1, one of core components of plant circadian oscillator, regulates age dependent leaf senescence by inhibiting ORE1 and activating GLK2 at the transcript level. Evening Complex (EC) modulates Jasmonate-induced leaf senescence through transcriptionally repressing MYC2, an essential component of JA signaling pathway to trigger leaf senescence. TIC, which regulates circadian rhythm with unknown mechanism, can modulate protein abundance of MYC2 with an unclear post-translational mechanism. ELF3 also regulates dark induced leaf senescence (DIS) through ORE1-dependent pathway by transcriptionally repressing PIF4. Whether other circadian clock components, such as Pseudo Response Regulators, are engaged into the regulation of leaf senescence awaits to be further investigated.