Cloning And Analysis The Salt Tolerance Related Genes From Salicornia Bigelovii Torr.

Salicornia Bigelovii Torr. is an euhalophyte plant in Salicornia, which can tolerate high Na+ concentration. It can tolerate over 20%～40% of sea water. The highest concentration for its growth is 5% NaCl. The plant contents 37% solubility salt in the young stem.Na+/H+ antiporter is a trans-membrane protein which plays an important role in plant salt tolerance. It responds to transport the Na+ out of plasma membrane from cytoplasm, or to vacuole from cell, which results the a decrease of Na+ concentration in cytoplasm, and protects the enzymes in cytoplasm against the poison by Na+. Clone and analysis of the Na+/H+ antiporter of Salicornia Bigelovii Torr. are preliminary to understand this gene in molecule level. Transformation of Na+/H+ antiporter into mode plant can research the mechanism of plant salt tolerance, and the function of this gene in plant salt tolerance thoroughly.In this research, we designd primers according to the homology of Na+/H+ antiporter, and clone the Na+/H+ antiporter gene form Salicornia Bigelovii Torr. by RT-PCR. The gene (named NP) is 2591bp length and was registered as DQ157454 in GeneBank. This cDNA sequence contains a 1683bp open reading frame (ORF) and encodes a polypeptide of 560 amino acids weight about 62.1KD. The result from the phylogeny analysis shows that NP is more close to the organellar Na+/H+ antiporters than plasma membrane Na+/H+ antiporters. It indicates that the NP is more likely to locate on member of vacuolar, and responds to transport Na+ into the vacuole from cytoplasm.The open reading frame of NP gene was inserted into plant expression vector pVKH-35S-pA, which resulted pVKH-35S-NP-pA. The recombinant vector was introduced into Arabidopsis thaliana by using vacuum infiltration method. After three generation selection (T3) through Hygromycin resistence, single-locus and homozygote transgenic lines were obtained. The transgenic Arabidopsis thaliana have higher salt tolerance than wild-type Arabidopsis on the MS medium with 200mmol/L NaCl.Salt tolerance of plant is a complex character and corporately regulated by many genes. In order to deeply research the mechanism of the plant salt tolerance. We should study all...