Isolation Of ATP Synthase Subunit E Gene In Sorghum (Sb ATPase-E) And Its Functional Analysis Related To Stress Tolerance

Drought is a major environmental stress seriously limiting plant growth and crop productivity. Using of genetic engineering becomes an important approach to improve drought resistance of crops. In this method, getting useful and valuable genes is the bottle-neck of the approach. Therefore, discovering drought- resistant gene quickly and efficiently is quite important in crop breeding.The FOX(Full-length cDNA Over-expressing gene) hunting system is unique in that only fl-cDNAs are required for the functional analysis of genes. First, this experiment screening drought resistance related genes from the sorghum’s full-length cDNA library which built in the early. Then do functional analysis on SbATPase-E(the ATP synthase subunit E gene) in sorghum.The main results as follows:(1)Isolation of drought resistance related genes in sorghum using the FOX hunting systemThe laboratory has constructed sorghum FOX Arabidopsis lines, treated the transgenic Arabidopsis thaliana T1 plants with drought, and harvest seeds of survival plants. Through identify the phenotype and molecular level of drought resistant T3 plants, we get seven drought resistance related genes.(2)Studying stress resistance function of SbATPase-E gene in transgenic Arabidopsis thaliana. Identified the function of the SbATPase-E gene which selected from seven drought resistance related genes. We found that the gene of transgenic Arabidopsis thaliana could improve the drought and salt resistance. In order to further study the function of the gene, we identified the over-expression transgenic Arabidopsis plants genes related to salt and drought tolerance, the seed germination rate and the stress resistance. We found that, over-expression transgenic Arabidopsis thaliana plants have a higher seed germination rate after treated with NaCl and ABA,and have a more extensive root system compared with the wild type plants after treatment with mannitol and sodium chloride. The more extensive root system in transgenic Arabidopsis thaliana plant may be the main reason for the improveddrought and salt tolerance under tolerance environment. SbATPase-E gene expression increased significantly in the sorghum seedling after treated with NaCl and ABA.Moreover, through the analysis of the expression of the other drought resistance related genes, we can find that the expression level of DREB2 A, P5CS1, RD29 A,RAB18 and ABI1 in the transgenic plants under drought condition were higher than that in the wild type plants, so as the expression of SOS1, SOS2 and SOS3 in the transgenic plants under high salt treatment were also higher. The up regulation of these genes’ expression level might be the main molecular mechanism of the improved stress resistance in these transgenic plants.