Generation Of Transgenic Wheat Homozygous Lines Expressing ABP9 And Characterization Of Their Tolerance To Drought And Nitrogen Deficiency

Drought is an important factor that restrict the yield improvement of crops and the over application of nitrogen has caused serious eco-system pollution. Our laboratory has cloned a bZIP transcription factor-ABP9 from the cDNA library of maize, which can interact with the cis-acting element of Cat1——ABRE2. According to the function study of ABP9 in Arabidopsis Thaliana, ABP9 can significantly improve its tolerance to abiotic stress such as drought, salinity and cold. Starting from the creation of transgenic wheat expressing ABP9, we further identified the transgenic wheat's tolerance to the stress of drought and low-nitrogen and created good germplasm resources for the wheat breeding. Results of the study are as following:(1) From 2006 to 2009 we have successfully transformed ABP9 gene driven by three different promoters into two varieties of SHI4185 and NINGCHUN4 by the method of microprojectile bombardment and obtained the T0 transformed plants. According to the detection of T0-T4 transformed plants by PCR, we obtained one pure line of Ubi-ABP9 SHI4185 and Ind-ABP9 SHI4185 respectively ,two pure lines of Ubi-ABP9 NINGCHUN4 . According to Southern blot and Northern blot, we further confirmed the results of PCR and the expression of ABP9 in the wheat.(2) We conducted drought tolerance experiment in the two T2 transgenic lines of SHI4185(Ubi-ABP9SHI4185 and Ind-ABP9 SHI 4185). The results showed that the phenotypes of the two transgenic lines under the drought stress and survival rate have been significantly improved.(3)We conducted drought tolerance experiment for the pure lines of transgenic ABP9 SHI4185 in ports in 2009 and 2010. Results showed that the phenotype of transgenic lines has been greatly improved. The results of 2009 showed that under drought stress the height, biomass, relative water content, yield and yield components have been remarkably improved and statistical analysis showed that the difference of yield and yield components between SHI4185 and Ubi-ABP9 SHI4185 is significant on the level of 1% and the above indexes are not significant between SHI4185 and Ubi-ABP9 SHI4185 under normal conditions.(4) According to the Real-time Quantitative PCR, we confirmed the induction of ABP9 in maize under the conditions of low nitrogen. We conducted the low-nitrogen tolerance experiment with pure lines of Ubi-ABP9SHI4185 in the sand and vermiculite in 2009 and 2010 respectively. Results of 2009 and 2010 showed that the growth and leaf color of Ubi-ABP9SHI4185 have been greatly improved comparing with SHI4185. Results of 2009 showed that the growth, chlorophyll, yield and yield components have been greatly improved,too. The differences of height,biomass,length of panicle and spikelets per panicle between SHI4185 and Ubi-ABP9SHI4185 are not significant and yield per plant, 100-grain weight and number of panicle of Ubi-ABP9SHI4185 are significantly improved comparing with SHI4185. The results of low-nitrogen tolerance experiment in vermiculite with Ubi-ABP9NINGCHUN4 are basically consistent with that of Ubi-ABP9 SHI4185. The above results from 2009 to 2010 have showed that ABP9 can significantly improve wheat's tolerance to drought and low nitrogen stress and has no obvious negative effect on the growth and yield of the wheat under normal conditions.