Research The Function Of OsCBL5 In Salt Tolerrance Signal Transduction In Rice

Calcium serves as a critical messenger in many adaptation and developmental processes. Calcium signals are detected and delivered by sensor proteins such as CBLs and CDPKs. In plants, the calcineurin B-like protein (CBL) family represents a unparalleled group of calcium sensors and plays a key role in decoding calcium transients by peculiarly interacting with and regulating a family of protein kinases (CIPKs). Several CBL-CIPK complexes have been identified that connect Ca2+ sensing with different physiological responses through a range of target proteins. Of these, the best known example is the salt overly-sensitive (SOS) pathway, a SOS3 (CBL) family protein SCABP8 (CBL 10) is operative in shoots The SCABP8-depen-dent SOS pathway activates SOS1 and Na+ efflux, thereby regulating net intracellular accumulation in shoots SOS2 phosphorylated SCABP8, which stabilized the SCABP8-SOS2 complex association with the plasma membrane and increased SOS1 antiporter activity Thus, SOS3 primarily interacts with SOS2 in roots and SCABP8 with SOS2 in shoots to facilitate recruitment of the complex to the plasma membrane, activate SOS1 Na+/H+ antiporter activity, and coordinate Na+ homeostasis and salt tolerance. The CBLs pathway compromise ABA dependent and ABA in-dependent pathway. The AtCBL1 and AtCBL9 all be interacted with AtCIPK23 to activate a downstream protein AtAKT1 which confer it tolerance the low K+condition in arabidopsis, Atcb19 mutant is sensitive’to ABA and Atcbll is not sensitive to ABA, which indicate that AtCBLl and AtCBL9 acted thought different pathway.CBL5 serves as crucial regulator of salt tolerance in rice.CBL5 over-expression can endow post-germination it sensitive to salt stress while tolerate with plant hormone ABA in rice, furthermore, we found that if OsCBL5 over-expression it was only confer rice sensitive to Na+ not other anion such as Cl- and NO3-.We measured the shoot and root Na+and K+ content which was imposed to high NaCl concentrate in different days by atomic absorption spectroscopy,finding out the shoot Na+concentrate higher than wild type and the root one was lower then wild type no matter whether it was imposed to high NaCl,and the more days it was imposed to high NaCl the bigger distinction both in shoot and root.while the K+ content had not obvious different.it indicted that OsCBL5 can regulate some gene to enhance rice capacity of transport Na+ from root to shoot.With Real Time PCR analysis we found that OsCBL5 confer rice sensitive to salt stress may by up-regulate shoot dawn-stream OSA1 and down-regulate OsHKT2;1,OsHKT2;3 and OsHKT9 genes expression and reducing ROS eliminated power gene like OsCATAl,other-while we also found OsCBL5 up-regulate OsELF3 expression in shoot and finally may regulate rice flowering or physiological cycle in high NaCl condition.