Studies Of The Rice Defences Responsitive P450 CYP72A Gene Cluster Expression And Defense Regulator SGT1

Rice is one of the most important crops in the world and the model of monocots as well, and its mechanism of disease resistance has been attracting researchers. In past decade, the greatest progress in plant disease resistance has been achieved in the establishment of "gene for gene" molecular interaction model and identification of a series of R genes. However, most of the cloned R genes confer race-specific resistance. Then the focus now forwards downstream regulators of resistance signaling.P450 genes are widely involved in development and defense of plants. Based on previous screening, we found a P450 gene cluster probably involved in rice defense. The gene cluster belongs to the CYP72A family (CYP72A17-23). We isolated the gene clones and preformed analysis of expression profiles of the genes under pathogen attack and development and tissues. Our current studies show that members of the CYP72A family can be classified into two sub-groups. Of 7 members, CYP72A18, 19, 23 were induced differentially by the rice blast fungus M. grisea in resistant H7R and susceptible H7S plants. And 6 members except CYP72A20 showed expression pattern of spatial and temporal specificity; CYP72A20 might be a pseudogene because we did not detect its transcript in all cases. Our results probably shed a light on studies of P450 genes in rice defense and development.Defense signalsome has greatly progressed due to the finding of the role of SGTl-involved protein degradation in disease resistance. We cloned SGT1 ortholog in rice, OsSGTl, and constructed the OsSGTl genomic and cDNA overexpression trangenic constructs in both sense and antisense ways. We introduced these constructs into the model variety Taipei309 and obtained transgenic plants. We also constructed a prokaryotic expression plasmid, and harvested OsSGTl fusion protein produced in E.coli to develop antibodies. These work provides the fundamental basis for the continuous studies of OsSGTl function in rice disease resistance and obtaining transgenic rice of resistance.Master Candidate: Wang Yaling Speciality: Botany Supervisor: Prof. Hu Baozhong Prof. He Zuhua...