Oryza sativa sequence reads

As sessile organism, plant must defend against multiple stresses such as soil salinity, osmotic or drought environment. Circadian clock system helps plants to perceive environmental changes and challenges, transmit these signals to cells and adjust their growth and metabolism in order to survive and reproduce. Compared with the better knowledge on how plants defend against stress-caused impairment on Arabidopsis, much less is known about how these stressful signals are integrated with circadian clock to control rice growth in threatening environment. Here we revealed core clock-related protein CIRCADIAN CLOCK ASSOCIATED 1 (OsCCA1) plays an essential role in integrating the abscisic acid (ABA) signaling pathway to confer soil salinity, osmotic and drought stresses tolerance in rice. The molecular mechanism was analyzed by transcriptome combined with DNA affinity purification sequencing (DAP-seq), which contribute a more integrative understanding of cross talk between OsCCA1 and its binding targets. In particular, we identified that the GATATTT motif is required for OsCCA1 to bind the promoter of its target genes, and found that OsCCA1 directly activates transcriptions of OsPP108 and OsbZIP46 to modulate a wide spectrum of stress-responsive genes thereby enhancing multiple stress resilience. Our finding clarifies the complex relationship between plant circadian clock and the regulatory mechanism of salt-inducible gene expression, which initially represent a molecular link that clock orchestrates ABA signaling pathway and defense response in rice.