Analysis Of Several Rice Circadian Clock Genes In Regulating Disease Resistance To Magnaporthe Oryzae

Plants have developed a complex disease resistance mechanisms in the long-term co-evolution with pathogens.The circadian clock is the internal time measuring machinery that integrates temporal information with environmental cues in regulating plant growth and development.Recent studies have established a role of the circadian clock in defense response in the model plant Arabidopsis.Rice shares conserved core clock genes with Arabidopsis.However,whether the circadian clock of rice is involved in rice resistance to pathogens,in particular to oryzae,a fungal pathogen causing devastating rice blight disease,remains unknown.In this study,the function of OsGI,a candidate clock gene was evaluated,especially its resistance to Magnaporthe oryzae.then,OsGI-Cas9 mutant will be constructed through CRISPR/Cas9 system.Furthermore we constructed reporter lines expressing the luciferase driven by clock gene promoters,whichse materiwill be used to generate transgenic lines for clock activity assay under various defense conditions.In current study,the results were as follows:1)OsGI enhanced resistance to rice blast fungus.we identified the genotype of T-DNA inserted mutants,OsGI,OsCPR5,and OsCRRL.The results showed that the genotypes of OsGI were homozygote and theheight of the nutantrice was dwarf when gene OsGI destroyed.The OsGI T-DNA insertion lines enhanced resistance to rice blast fungus.Also,OsGI-Cas9 mutant has been constructed through CRISPR/Cas9 system.2)we constructed reporter lines expressing the luciferase driven by clock gene promoters.Some candidate clock genes were predicted by bioinformatics,the result revealed that GI,TOC,CCA,PRR9,LUX and CPR5 are conserved with clock genes in Arabidopsis.Whereafter,we constructed reporter lines expressing the luciferase driven by those clock gene promoters.The resulting constructs have been used to generate transgenic lines for clock activity assay under various defense conditions.3)The expression level of clock genes were changed after infection with rice blast fungus.Rice plants inoculated with or without M oryzae were havested in a time course.The qRT-PCR was employed to evaluate the expression pattern of some candidate genes.Rice clock-related genes,GI,TOC,CCA,LUX and PRR9 are involved in response to rice blast fungus infection,and play roles at different time.The expression levels of GI and PRR9 were significantly upregulated 30 hpi;LUX significantly upregulated 36 hpi;CCA increased significantly 18 hpi;TOC 6 hpi.