Leucine-rich repeat receptor-like kinase OsASLRK regulates abscisic acid and drought responses via cooperation with S-like RNase OsRNS4 in rice

Both leucine-rich repeat receptor-like kinases (LRR-RLKs) and S-like RNases play key roles in abiotic stress response regulation. However, their relationship in together facing with abiotic stress has not yet been revealed. Here, we characterized the function of a LRR-RLK-coding gene in rice, OsASLRK, which is significantly up-regulated by multiple abiotic stresses. The Osaslrk mutant was less sensitive to exogenous abscisic acid (ABA) and more sensitive to drought, whereas the rice lines with OsASLRK ectopic expression displayed reverse phenotypes. The expression of a set of ABA- and drought-related genes was altered in the Osaslrk mutant and OsASLRK ectopic expression rice lines under drought treatment. Further investigation indicated that OsASLRK interacted physically with S-like RNase (OsRNS4), and this interaction could be enhanced by ABA and drought. The expression of OsRNS4 was suppressed in the Osaslrk mutant and elevated in the OsASLRK ectopic expression rice lines in response to ABA and drought. Furthermore, OsASLRK can phosphorylate OsRNS4 in vivo and vitro. Genetic analysis showed that OsRNS4 has similar functions in ABA and drought responses to OsASLRK. Collectively, our findings reveal that the LRR-RLK OsASLRK plays important roles in ABA and drought responses via cooperation with S-like RNase OsRNS4 in rice.