Agrobacterium Tumefacien Mediated Transformation Of PRK Gene Into Rice

According to differences in carbon assimilation pathways in photosynthesis, land plant species may be distinguished into three types: C₃, C₄, and CAM (crassulacean acid metabolism). Compared with C₃ plants, C₄ plants have higher eficiency in photosynthesis, water utilization and nutrient utilization because of their unique Kranzs tructureand C₄ pathway. These advantages of C₄ plants are especially valuable under the circumstance of high temperature, high light intensity and drought. Therefore, it is neccesary to improve the photosynthetic properties of C₃ rice plants by introducing the photosynthetic traits of C₄ plants into them. PRK gene is the key enzyme for the C₄ photosynthensis. In this study, PRK gene was transformed into Ribenqing, a rice variety, in an Agrobacterium-mediated way. The aim of doing that is to increase the amount of its PRK gene and make the transgenic rice plants have the photosynthesis characteristics of C₄. In addition, a primary study on photosynthetic physiological change was also done in the present study. This study provides a standard practice method for further rice engineering and furnishes our knowledge of improving photosynthesis. The main results are as follows:1. A pair of primers was designed to clone the CAB gene of rice, and PRK gene according to the published gene sequence. The expression vector was successfully constructed. The recombinant expression vector was named CAB- PRK- pSN1301, and then it was used to transform transgenic Agrobacterium EHA105.2. Expression vector PRK-CAB-pSN1301 was used to transform transgenic rice with the introduction of Agrobacterium EHA105. Transgenic callus of rice were screened out on nutrient medium with hyg by using rice. PCR detection of hyg in 10 putative transgenic plants confirmed that the PRK gene was transformed into the geneome of these putative transgenic callus.3. The photosynthesis characteristics on different leaf age at one developmental stage between mutant and WT were compared. The Fv/Fm ratio, reflecting the maximal photosystem II photochemical efficiency, was not changed in different age leaves of mutant and Wt.4. Chlorophyll contents per unit FW were increased from germination to the forth leaves in both Wt and mutant plants, and the mutant is higher than Wt.