Physiological and metabolic enzymes activity changes in transgenic rice plants with increased phosphoenolpyruvate carboxylase activity during the flowering stage
文献类型： 外文期刊
作者： Xia, Li 1 ; Cao, Wang 1 ;
作者机构： 1.Jiangsu Acad Agr Sci, Inst Food Crops, Jiangsu High Qual Rice Res & Dev Ctr, Nanjing 210014, Jiangsu, Peoples R China
2.Nanjing Normal Univ, Coll Life Sci, Jiangsu Key Lab Microbes & Funct Genom, Nanjing 210097, Jiangsu, Peoples R China
关键词： Phosphoenolpyruvate carboxylase (PEPC);Transgenic rice;Carbon metabolic enzyme;Nitrogen metabolic enzyme;Photosynthesis
期刊名称：ACTA PHYSIOLOGIAE PLANTARUM （ 影响因子：2.354； 五年影响因子：2.711 ）
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收录情况： SCI
摘要： To compare the differences in physiology and metabolism between phosphoenolpyruvate carboxylase (PEPC) transgenic rice and its control, untransformed wild rice, dry matter accumulation, soluble sugar, starch and protein contents and enzyme activitieswere determined in different plant parts during flowering. Results revealed that PEPC transgenic rice had higher dry weights for leaf, stem and sheath as well as panicle than the untransformed wild rice did, with the largest increase in the panicle. Soluble sugar and protein content in the grains of PEPC transgenic rice were significantly enhanced while starch content changed less. PEPC transgenic rice exhibited high levels of PEPC activity, manifesting in high net photosynthetic rates during flowering.Moreover, transgenic rice with high PEPC expression levels also had elevated levels of the enzymes such as sucrose-p-synthase and sucrose synthase, which may confer a higher capacity to assimilate CO2 into sucrose. Little increase in grain starch content was observed in transgenic plants due to the stable activities of starch synthase and Q enzyme. However, the PEPC transgenic rice plant induced the activities of nitrate reductase, glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, glutamine synthetase, and asparagine synthase to high levels, as compared with the untransformed rice plant. PEPC activity was correlated with protein content in grains and the enzymes of nitrogen metabolism, suggesting that high PEPC activity in transgenic rice might be able to redirect carbon and nitrogen flow by regulating some enzymes related to carbon or nitrogen metabolisms. These results may help to understand how the C3 plants possessing a C4-like photosynthesis pathway worked by expression of PEPC.
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