Cloning And Functional Analysis Of Cotton Salt Stress Responsive Gene GhSR13

With the land environment was deteriorated and saline area continues to expand, how to use saline effectively has placed in front of our reality problem. Cotton is a typical salinity of crop with high salinity and drought resistance, but salt-tolerant cotton varieties is still relatively scarce in the production of large-scale cultivation. Thus utilizing insensitive salt gene to improve salt tolerance of cotton by transgenic technology, and cultivate cotton excellent salt varieties is particularly important.In this study, we got a salt response related EST sequences by gene chip technology. Through analysis of the gene information database of Upland cotton, we cloned the full length CDS sequence of the gene,which named Gh SR13. The gene CDS is 1476 bp and the protein contains 492 amino acids. Then we analyzed GhSR13 gene bioinformatics information, and the results showed that GhSR13 belong to DDE_Tnp₁₆ Superfamily. Through combined NCBI database, tetraploid database of Cotton Institute,Chinese Academy of Agricultural Sciences（Anyang, China）, that found the genes which in tomato and Arabidopsis was more than 50% of homology analysis. The orthologous genes which in tomato and Arabidopsis were both predicted take part in salt stress response pathway.We analyzed the GhSR13 expression levels under the salt stress. The cotton root and leaf RNA was extracted and performed quantitative analysis after treating the seedling with 200 mm NaCl for 0 h, 1 h, 4 h,6 h, 12 h, 24 h. Through analyzed the expression level of GhSR13 in the root, indicated that the gene may be involved in salt stress response pathway.We constructed some vectors, such as GhSR13-GFP and Gh SR13-GUS, and then transformed into Arabidopsis protoplasts to investigate the gene functions under salt stress. The GFP fluorescence results showed that GhSR13 was located in the nucleus, and the GUS stain results indicated that the gene is expressed mainly in the root maturation zone. We went on to construct the GhSR13-PYES2 yeast expression vector and found that the colonies of yeast expression vector which containing the gene were grown not well as control under 200 m M NaCl and 10 mM LiCl conditions. Furthermore, we did the VIGS experiments and observed that the transgene plants leaves obvious wilting after 600 mM NaCl treatment,which showed higher wilting rate than the control plants. It seems likely that the gene which was interferedincreased the response to salt stress. We also transferred cotton GhSR13 gene into Arabidopsis plants, three lines（OE-2,OE-3,OE-4） seeds showed higher sensitive to salt stress in germination and root elongation experiments. Above all, GhSR13 gene is involved in the salt stress response in cotton.