Analysis Of Resistance In Transgenic Rice With OsCERK2 Gene To Bacterial Leaf Blight

Rice (Oryza sativa) is the most important food crop, and most people feed on it. With the increase of population and cultivated area per person is gradually decreasing, we must increase rice yield in order to meet the demand of people’s lives. Rice diseases, such as rice bacterial leaf blight, are important factors that affect rice production. Breeding for resistant varieties is a most economically and environmentally effective way to protect rice yield from losses caused by diseases.In this study, the Arabidopsis CERK1 was used to retrieve its homologous genes in the rice genome and a rice homologous gene CERK2, OsCERK2 was obtained. cDNA of OsCERK2 was isolated by RT-PCR. Overexpression vector driven by 35S promoter and RNA interference (RNAi) vector driven by maize ubiquitin promoter were constructed. These vectors were then transferred into rice by Agrobacterium-mzdiated transformation. Thirty TO transgenic plants were obtained from each vector. Homozygous transgenic lines were identified after multigenerational cultures and PCR detection. These homozygous transgenic lines were then tested for responses to cell wall extracts of pathogens and inoculation of rice bacterial blight Xanthomonas oryzae pv. oryzae (Xoo). The results were reported as follows.I. Bioinformatics analysis showed that OsCERK2 is a plasma membrane protein including a signal peptide, its extracellular domain includes an LsyM domain, its kinase domain includes a protein tyrosine kinase domain. Encoding protein consists of 712 amino acid residues, and its molecular weight is 76.852 kD, its theoretical pi is 6.50, its Instability index is 36.87, the protein is a stable protein, total number of negatively charged residues (Asp+Glu) is 67, total number of positively charged residues (Arg and Lys) is 63, Total number of atoms is 10753, its formula is C3420H5352N918O1031S32-3. After screening plants by multigenerational culture and PCR detection, the transgenic homozygous lines (OE30,OE42,OE56, OE57 and RNAi-54, RNAi-57) with genetic stability were identified.4. OsCERK2 homozygous plants treated by cell wall extracts of pathogens indicated that OsCERK2 might participate in PGN or chitin elicitor signaling.5. Inoculations with rice bacterial leaf blight pathogen Xoo strain PXO99 demonstrated that overexpression of OsCERK2 enhanced resistance to Xoo, while RNAi transgenic plants decreased resistance to Xoo, suggesting that remodeling of OsCERK2 expression pattern might alter rice response to Xoo. Our results provide the possibility to generate transgenic rice by gene expression remodeling.