Functional Analysis Of SlCBL4 And SlCBL8 In The Resistance To High Salinity

Calcium plays a crucial role as a second messenger in various environmental and developmental signaling pathways in plant cells.In plants,spatially and temporally distinct changes in cellular Ca2+ concentrations,are designated as "Ca2+ signatures" that are evoked in response to various stresses.Cellular calcium signals are detected and transmitted by sensor molecules such as calcium-binding proteins.In plants,the calcineurin B-like protein(CBL)family represents a unique group of calcium sensors and plays a key role in decoding calcium transients by specifically interacting with a family of protein kinases(CIPKs).Current researches suggest that CBL-CIPK signaling system involved in many biotic and abiotic stress in plants.Tomato is one of the completely sequenced model plants for identifying and characterizing genes.Despite CBL-CIPK signaling system is well studied in Arabidopsis,the functions of CBL-CIPK signaling system in tomatoes is still rarely reported.Therefore,it is important to study this aspect in tomatoes for enrich mechanisms of the stresses resistance determined by CBLs-CIPKs.We have already got the SICBL4 over-expressing and SICBL8 over-expressing/RNAi transgenic plants.Based on the above-mentioned,The results were shown as following:1.The SICBL4 over-expressing transgenic plants were treated with 200 mM NaCl during early seedling stage and adult stage,the Chlorophyll fluorescence parameter (Fv/Fm)and Na+ content related to salt stresses were examined.The results showed that the Chlorophyll fluorescence parameter(Fv/Fm)in SlCBL4 over-expressing plants decreased less than that of wild-type plant.The accumulation of Na+ in SICBL4 over-expressing plants also less than that of wild-type plants.These results suggest that SICBL4 over-expressing transgenic plants displayed notably increased tolerance to high salinity.2.The SICBL8 over-expressing and RNAi transgenic plants(W38,Nicotiana benthamiana)were treated with 200 mM NaCl,and examined the Chlorophy ?fluorescence parameter(Fv/Fm)and Na+ content.The results showed that SlCBL8 over-expressing transgenic plants displayed notably increased tolerance to high salinity than RNAi and wild-type plants.3.To further confirm the function of SICBL4 and SICBL8,we transformed the former constructed SICBL4 and SlCBL8 over-expressing vectors into cbl4 mutant and wild-type Arabidopsis.