Lian Ling, Wang Xiaowei, Zhu Yongsheng, He Wei, Cai Qiuhua, Xie Huaan, Zhang Muqing, Zhang Jianfu
Rice Research Institute, Fujian Academy of Agricultural Sciences, Fuzhou, Fujian Province, 350018, People's Republic of China.
Mol Biol Rep. 2014;41(4):2189-97. doi: 10.1007/s11033-014-3070-4. Epub 2014 Jan 29.
Phosphoenolpyruvate carboxylase (PEPC) is known to play a key role in the initial fixation of CO2 in C4 photosynthesis. The PEPC gene from sugarcane (a C4 plant) was introduced into indica rice (Hang2), a process mediated by Agrobacterium tumefaciens. Integration patterns and copy numbers of the gene was confirmed by DNA blot analysis. RT-PCR and western blotting results showed that the PEPC gene was expressed at both the mRNA and protein levels in the transgenic lines. Real-time PCR results indicated that expression of the sugarcane PEPC gene occurred mostly in green tissues and changed under high temperature and drought stress. All transgenic lines showed higher PEPC enzyme activities compared to the untransformed controls, with the highest activity (11.1 times higher than the controls) being observed in the transgenic line, T34. The transgenic lines also exhibited higher photosynthetic rates. The highest photosynthetic rate was observed in the transgenic line, T54 (22.3 μmol m(-2) s(-1); 24.6 % higher than that in non-transgenic plants) under high-temperature conditions. Furthermore, the filled grain and total grain numbers for transgenic lines were higher than those for non-transgenic plants, but the grain filling (%) and 1,000-grain weights of all transgenic lines remained unchanged. We concluded that over-expression of the PEPC gene from sugarcane in indica rice (Hang2) resulted in higher PEPC enzyme activities and higher photosynthesis rates under high-temperature conditions.
已知磷酸烯醇式丙酮酸羧化酶（PEPC）在C4光合作用中二氧化碳的初始固定过程中起关键作用。将甘蔗（一种C4植物）的PEPC基因导入籼稻（杭2），该过程由根癌农杆菌介导。通过DNA印迹分析确认了该基因的整合模式和拷贝数。RT-PCR和蛋白质印迹结果表明，PEPC基因在转基因株系的mRNA和蛋白质水平上均有表达。实时PCR结果表明，甘蔗PEPC基因的表达主要发生在绿色组织中，并在高温和干旱胁迫下发生变化。与未转化的对照相比，所有转基因株系均表现出更高的PEPC酶活性，其中转基因株系T34的活性最高（比对照高11.1倍）。转基因株系还表现出更高的光合速率。在高温条件下，转基因株系T54的光合速率最高（22.3 μmol m(-2) s(-1)；比非转基因植物高24.6%）。此外，转基因株系的实粒数和总粒数高于非转基因植物，但所有转基因株系的粒重充实率（%）和千粒重保持不变。我们得出结论，甘蔗PEPC基因在籼稻（杭2）中的过表达导致在高温条件下具有更高的PEPC酶活性和更高的光合速率。
