Transcriptional activation and phosphorylation of OsCNGC9 confer enhanced chilling tolerance in rice

摘要

Low temperature is a major environmental factor that limits plant growth and productivity.Although transient elevation of cytoplasmic calcium has long been recognized as a critical signal for plant cold tolerance,the calcium channels responsible for this process have remained largely elusive.Here we report that OsCNGC9,a cyclic nucleotide-gated channel,positively regulates chilling tolerance by mediating cytoplasmic calcium elevation in rice (Oryza sativa).We showed that the loss-of-function mutant of OsCNGC9 is defective in cold-induced calcium influx and more sensitive to prolonged cold treatment,whereas OsCNGC9 overexpression confers enhanced cold tolerance.Mechanistically,we demonstrated that in response to chilling stress,OsSAPK8,a homolog of Arabidopsis thaliana OST1,phosphorylates and activates OsCNGC9 to trigger Ca2+ influx.Moreover,we found that the transcription of OsCNGC9 is activated by a rice dehydration-responsive element-binding transcription factor,OsDREB1A.Taken together,our results suggest that OsCNGC9 enhances chilling tolerance in rice through regulating cold-induced calcium influx and cytoplasmic calcium elevation.