Overexpression of Phosphoenolpyruvate Carboxykinase Increases Photosynthetic Efficiency and Salt Tolerance in Rice

Salinity stress is one of the major obstacle worldwide for the glycophytic crop production, including rice. It alters the cellular metabolism, causing significant crop destruction resulting in substantial reductions in yield. Through genetic engineering, the oxidative stress can be decreased while increasing the photosynthetic capability by using C3 transgenic plants that produce the C4 enzymes like phosphoenolpyruvate carboxykinase (PEPCK) at a high level. In this research, we evaluate the efficiency of transgenic rice plants (Oryza sativa L. cv. IR64) over-expressing PEPCK genes to act against salinity stress as well as increasing its photosynthetic efficiency. The T1 transgenics showed increased levels of several biochemical factors, including ascorbate peroxidase (APX), malondialdehyde (MDA), glutathione reductase (GR) and guaiacol peroxidase (GPX) activities suggesting the existence of an effective antioxidant defense mechanism that helps the plants to deal with oxidative damage driven by salt stress. The photosynthetic parameters like chlorophyll contents, net photosynthetic rate, intercellular CO2 content and stomatal conductance were elevated in transgenic plants when compared with the control plants (null seggregant). It also exhibited higher agronomic characteristics than the control plant. Our findings add a conclusive evidence of PEPCK gene’s potential role in regulating salt stress response and tolerance of rice plants.