Cloning, Expression Analysis And Genetic Transformation Of The BdWRKY55 And BdWRKY83 Genes In Tobacco

Various abiotic stresses including drought, high salinity, extreme temperature, etc. severely affect plant growth and development, and decrease the productivity and quality of crops. During long-time evolution process, plants have developed elaborate metabolisms e.g. by activating transcriptional factors to enhance or inhibit downstream genes' expression, and adapt to those environmental changes. WRKY transcriptional factors have been shown to play important roles in plants' growth and development and in response to bio- and abiotic stresses. While there is few reports on WRKYs of Brachygodium distachyon, a new model monocot, whose genome is highly homologous with wheat.In the present study, two WRK Y genes from B. distachyon were cloned successfully. Their expression profiles in different organs and in response to abiotic stresses and signaling molecules, subcellular localization were analyzed. Transgenic tobaccos overexpressing the two WRK Y genes were generated by using agrobactirium- mediated genetic transformation techneque. The main results are as follows:(1)Based on bioinformatic analysis,c DNA of two WRKY genes, designated BdWRKY55 and BdWRKY83,respectively, were cloned by RT-PCR. Sequence alignment results indicated that both these WRK Y belong to subgroup III.( 2) Subcellular analysis using onion epidermal cells method showed both BdWRK Y55-GFP and Bd WRKY83-GFP were localized in nucleus.(3)Their expression profiles analyses by semi-quantatative RT-PCR method showed that BdWRKY55 and Bd WRKY83 were expressed in all organs examined with highest expression in leaves. Bd WRK Y55 and BdWRK Y83 expression in response to different stresses and signaling molecules were different. PEG?ABA?H2O2?cold and heat treatments all downregulated BdWRK Y55 expression. While except for cold,all above mentioned stresses and signaling molecules treatments upregulated BdWRKY83 expression.(4)Transgenic tobacco overexpressing BdWRKY55 and Bd WRKY83 were obtained. Preliminary phenotypic observation showed that overexpression of BdWRKY83 in tobacco could obviously enhanced their tolerance to drought stress.Results of present study provided useful information for further investigation on the functions of these two BdWRKYs.