Safety Assessment Of Transgenic Drought-resistant Wheat With DREB Gene And Proteomic Research Of Drought-resistant Mechanism

The AP2/EREBP transcription factors, which participate in the regulation of a variety offunctional gene expression, are widely present in many plants. Among them, DREB transcriptionfactor play an important role in stress-tolerance response. DREB transcription factors bind to theDRE/CRT cis-acting elements in the promoter regions of many stress-related genes and inducetheir expression which, in turn, confers abiotic stress tolerance to plants. After several years ofearly research, we obtained the transgenic wheat lines that expressed TaDREB3, TaDREB4 andGmDREB1 under constitutive CaMV35S promoter and showed drought stress tolerance. In thisstudy, the functional efficiency and the competition for survival ability of the transgenic wheatwere evaluated to evulate the influence of the overexpression of DREB on transgenic wheat.Based on the phenotype characters, physiology parameters and protein response to salt anddrought stress, we deciphered the mechanisms underlying drought and high-salinity tolerance in35S:DREB transgenic wheat. The results are as follows:1. We evaluated the functional efficiency of transgenic wheat MG344, MG199, T349 andwild-type Jm19. The results showed: The transgenic wheat that expressed TaDREB3,TaDREB4 and GmDREB1 under constitutive CaMV35S promoter showed salt and droughtstress tolerance in the seedling stage and the whole growning season.2. We evaluated the competition for survival ability of transgenic wheat MG344, MG199, T349and wild-type Jm19..Under the normal growning conditions, the ratio of germination, thephysiological indicators and the agricultural characters of transgenic wheat and wild-type hadno significant differences in the germination stage, the seedling stage and the whole growthperiod. The transgenic wheat had the same competition for survival ability with the wild-type.3. Using the proteomic approach, the protein responses to the drought and salt stress of thetransgenic wheat and Jm19 were studied. Comparing with Jm19, there were 15, 23 and 16protein spots differentially expressed in T349, MG344, MG199 under drought stress, and 17,18 and 13 under salt stress. According to the results of MALDI-TOF-MS idendification, theseproteins respectively belong to osmotic stress-related, oxidative stress-related, photosynthesis-related proteins and some unknown function proteins.4. Based on the phenotype characters, physiology parameters and protein response to salt anddrought stress, we deciphered the mechanisms underlying drought and high-salinity tolerancein 35S:DREB transgenic wheat: the overexpression of DREB in transgenic wheat probablyinduce the differentialy expression of some proteins to reduce the damage of osmotic stressand oxidative stress, and improve the photosynthesis of transgenic plants, finally to improvethe drought and salt tolerance of transgenic wheat.The results of this study provide theoretical basis for us to further study the molecularmechanism of the DREB transcription factors in regulating the stress signal networks in plant,and good candidate gene resources for improving crop stress tolerance using gene engineering.Also provide important information for the management and release in the environment of thetransgenic wheat.