Received: 25-07-2014 / Accepted: 09-10-2015
OsCIPK15is a key regulator of starch degradation in rice due to submergence. This gene receives submergence signal via calcineurin B-like (OsCBL) proteins, which act as the Ca2+sensors, and whose role has yet to be established. In the present study, we compared the transcriptional regulation of CBLsin germinating rice embryos under water submergence. The trans-activation of OsCBLpromoters was tested by examining the effects of Ca2+. We used rice protoplasts to study the OsCBLs-OsCIPK15 protein interactions. We found that OsCBL4and OsCBL5were transcriptionally regulated under submergence.The Ca2+sensors OsCBL4 and OsCBL5 wereinvolved in this system and interactedon the plasma-membrane with OsCIPK15 in Ca2+dependent manner. Our results suggest that Ca2+signaling formed under submergence are inducedby OsCBL4and OsCBL5 which then interact with OsCIPK15 to activate genes involving instarch catabolism to provide energy for rice germination.