Developing Indica Rice With Phosphoenolpyruvate Carboxylase Gene (PEPC) From Sugarcane And Their Analysis Of Physiologic Characteristics In Relation To Photosynthesis

Rice (Oryza sativa) is one of the staple crops which is the major source of calories and nutrition for almost 50% populations in the world. The genetic engineering method which C₄ genes related to photosynthesis were transformed to rice was one of methods increasing the yield for rice because of C₄ photosynthesis with higher transforming rate of photosynthetic energy. The PEPCase was a key enzyme for C₄ photosynthesis. It catalysis the first reaction in the mechanism of CO₂ concentration, which was the intitially CO₂ fixation. So the photosynthetic rate of C₄ crops was higher that of C₃ crops, especially in the condition of high temperature and strong light.The enzyme activity of Rubisco for rice was lower grew in the condition of high temperature and strong light. So it was not conducive to assilimate and fix CO₂. resulting in the decrease the rate of CO₂ fixtion. Wherase, sugarcane, one of C₄ plants, still grew well in the condition of high temperature and strong light and wet environment. In the meanwhile, the sugar was also accumulated in the condition of lower temperature and drying environment. The indica restorer line Hang2 were transformed with pepc gene from sugarcane mediated with Agrobacterium tumefaciens to improve the photosynthetic rate of transgenic rice with pepc. Furtherly, the new germplasms of rice with higher photosynthesis were created and bred the new varieties of higher photosynthesis. The main conclusions were made as follows.1. The PCR results showed that the pepc gene from sugarcane could be deteced in 132 regenerated plants from 600 transformed plants, and so was the marker gene hyg. The statistical results indicated that indica rice Hang No.2 was transformed by pepc gene, with a transformation frequency of 18.5%.2. The Southern blotting showed that the gene pepc from sugarcane and the marker gene hyg had been integrated to the rice genome of restorer line Hang.2.3. The RT-PCR results indicated that the gene pepc from sugarcane was expressed in the mRNA for transgenic plants. 4. Analysis of total protein and PEPCase activity in the leaves of transgenic rice showed that the total protein concerntrations and the PEPCase activity of transgenic plants were higher than those of the control rice.5. The RCR results of T₁ generation of transgenic plants showed that pepc gene could be inherited in the progeny of transgenic plants.6. The results of photosynthetic rate of T₁ progencies of transgenic plants showed that pepc gene from sugarcane could improve the photosynthetic rate of transgenic rice under the certain condition.