Abstract: Cotton is an important crop in the reclamation of saline and alkaline land. In this study, a novel DREB (dehydration responsive element binding) transcript factor named GhDREB2B (GenBank accession No.GQ848094) was cloned from the upland cotton (Zhongmiansuo 49) by RT-PCR method based on the information of screening the cotton fiber EST (express sequence tag) database and contig the candidate ESTs under salt treatment. The full length of GhDREB2B encoded a polypeptide of 351 amino acid residues with a predicted molecular weight of 39 kD. The deduced amino acid sequences had the homology with the members of DREB family in plant kingdom: populus, soybean and Arabidopsis thaliana, etc. They shared the conserved domain of AP2/ERF in the deduced protein. This gene was predicted as a novel DREB factor in tetreploid cotton. Quantitative real-time RT-PCR analysis revealed that the higher expression levels of GhDREB2B gene were detected under salt treatment and its expression level was high under 0.7% NaCl treatment; however, its expression was not affected by the plant hormone of ABA (abscisic acid). These results indicated that GhDREB2B gene plays an important role under salt tolerance and gives us the clues of using the factor in cotton by transgenic method．

Key words: cotton, DREB transcript factor, GhDREB2B, quantitative real-time PCR, salt tolerance, ABA treatment