The Functional Analysis Of Rice Disease Defense-related Genes OsRBCS And OsUBC2

Rice sheath blight, which is one of the most serious rice fungal diseases, is quitedifficult to prevent and control, while the continuous development of transgenictechnology has made it possible to quickly cultivate resistance varieties against thedisease. In order to quickly cultivate disease-resistant varieties through transgenictechnology, first of all, effective resistance genes are necessary.The ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit (OsRBCS)gene and ubiquitin-conjugating enzyme E2(OsUBC2) gene were found throughsuppression subtractive hybridization and homology cloning, which showed to beinduced by the infection of rice sheath blight and rice blast. The overexpressionvectors of the two genes were constructed and transformed into rice Minghui86byAgrobacterium respectively. And transgenic lines with increased resistance againstrice sheath blight and rice blast have also been obtained through disease resistanceidentification, which suggested that OsRBCS and OsUBC2were both related to ricedisease resistance.For further study the functions of the two genes, the resistances of the abovetransgenic lines were carefully identified again, and the transcription amounts oftarget genes were analyed by semi-quantitative RT-PCR. In addition, theaccumulation changes of reactive oxygen in the above transgenic lines which isrelated to the rice defense response were also detected. Besides, RNAi vectorspTCK303-OsRBCS and pTCK303-OsUBC2were constructed and then successfullytransformed into rice cultivar Kitake by Agrobacterium-mediated transformation.The GUS gene and the hygromycin resistance gene were amplified by PCR, whichprovided the initial proof that the target gene was integrated into the rice genome.GUS staining results showed that the transgenic rice leaves could be dyed blue,indicating that RNAi vectors had been successfully expressed in vivo. Until now213GUS staining positive transgenic plants and156T1transgenic seeds were harvested.Follow-up analysis of disease-resistance characteristics of OsRBCS and OsUBC2RNAi lines is of great significance for further clarification of the functions of OsRBCS and OsUBC2.