Nicotiana sylvestris calcineurin B-like protein NsylCBL10 enhances salt tolerance in transgenic Arabidopsis

Key message Nicotiana sylvestris calcineurin B-like protein NsylCBL10 improves tolerance to high-salt stress through better maintenance of Na + balance. Abstract The calcineurin B-like (CBL) proteins represent a unique group of plant calcium sensors and play an important role in regulating the response of a plant cell to the stress. Although many studies have been made in Arabidopsis ( Arabidopsis thaliana ), rice ( Oryza sativa ) and poplar ( Populus trichocarpa ), the characterization and elucidation of the functions of CBLs in tobacco have not yet been reported. In this study, NsylCBL10 , a CBL gene showing higher similarities to other CBL10 genes, was cloned from Nicotiana sylvestris . NsylCBL10 is expressed in most of the tobacco tissues, and the protein targets to the plasma membrane specifically. Over-expression of NsylCBL10 enhanced the salt tolerance of Arabidopsis wild type plants greatly, and rescued the high-salt-sensitive phenotype of Arabidopsis cbl10 mutant. The analysis of ion content indicated that over-expressing NsylCBL10 in plants is able to maintain a lower Na + /K + ratio in roots and higher Na + /K + ratio in shoots, compared with cbl10 mutant. The results suggest that NsylCBL10 might play an important role in response to high salinity stress in N . sylvestris , by keeping a better ionic homeostasis to reduce the damage of toxic ion to the plant cell.