Improvement of wheat drought and salt tolerance by expression of a stress-inducible transcription factor GmDREB of soybean (Glycine max)

Under stress conditions such as drought, high-salinity and low-temperature, the transcription factor of DREB (dehydration responsive element binding proteins) improved efficiently stress resistance by regulating the expression of its downstream genes with various environmental stress resistance in plants. GmDREB gene (GenBank Accession No. AF514908) encoding a stress-inducible transcription factor was cloned by screening a cDNA library of Glycine max cv. Jinong 27 with yeast one-hybrid method. GmDREB gene was 910 lip in length and encoded 174 amino acids containing a conserved AP2/EREBP DNA-binding domain of 58 amino acids. Two conserved functional amino acids, valine and glutamic acid, were located on the 14th and the 19th amino acid residues in the conserved structural domain. An alkaline amino acid region (KKR) related to a nuclear localization signal was at the N-terminal, while an acidic amino acid region (DDD) related to trans-activation was at the C-terminal. Plant expression vectors were constructed and transformed into wheat by bombardment. In total, 13 transgenic plants with Ubi::GmDREB and 11 transgenic plants with rd29A::GmDREB were identified from 103 regeneration plants by molecular analysis. The drought and salt tolerances of T, transgenic lines with Ubi::GmDREB or rd29A::GmDREB were demonstrated to be improved as compared to wild type. The result also suggested that both Ubiquitin and rd29A promoters could effectively drive the expression of the GmDREB gene and enhance drought and salt tolerance of T-1 plants.