Cloning And Functional Characterization Of A Rice Bacterial Leaf Streak And Bacterial Leaf Blight Defense-related Gene OsDRxoc8

Rice bacterial blight disease caused by Xanthomonas oryza sative pv. oryza and Rice bacterial streak disease caused by Xanthomonas oryzae pv.oryzicola, are two of the most devastating diseases of rice worldwide which caused tremendous yield loss each year. It is an economic and green strategy to control those diseases through improving rice defense system. In this study, we have cloned and charactered a rice disease resistance related genes, OsDRxoc8, which results in enhancing resistant to both Xoo and Xoc in transgenic rice. It is supported to elucidate the resistant mechanism of rice disease and to cultivate resistant rice variety with OsDRxoc8gene in the future.OsDRxoc8encoded a18.1KDa sHSP, which belongs to the Saccharomyces yeast small heat shock protein26(ScHsp26) gene family. As a chaperone, sHSP can inhibit excessive accumulation of protein, prevent cell damage, enhance stress resistance in plants. Through Agrobacterium tumefaciens-mediated transformation system, the we got OsDRxoc8overexpression and repressed expression transgenic rice lines. After pathogen assayed for RS105and PXO99with T1generation of transgenic lines, which have been screened out to affect the expression of OsDRxoc8with quantitive RT-PCR. The overexpression lines show to enhanced the resistance of both bacterial streak disease and rice bacterial blight disease, while RNAi lines show more susceptible to PXO99only. As OsDRxoc8belongs to a super gene family, it contains fifteen gene members whose share about71.0%similiarity of each other at amino acid level in rice genome. Associated with no clear effect obeserved on RNAi line after inoculation RS105, it is predicted that here may has gene redundancy for OsDRxoc8in RNAi lines.Compared with wild type, OsDRxoc8overexpression lines appear to dwarf, shorter and narrower blade, less tiller phenotype, but not for RNAi lines of OsDRxoc8. These phenotypic changes was cosegregated with genotype of transforred OsDRxoc8. The results suggestted that OsDRxoc8was aslo function on regulation of plant development and may has gene redundancy function in its RNAi lines.Above all, we concluded that the OsDRxoc8gene is a important factor involved in both plant development and disease resistancein rice.