Over-expression of RPEase gene promotes the growth and development of Arabidopsis thaliana

The Calvin cycle is an irreplaceable pathway for photosynthetic organisms to assimilate CO2 from the air and therefore plays a crucial role in plant growth and development. The ribulose-phosphate 3-epimerase (RPEase: EC 5.1.3.1) is one of the integral enzymes in the Calvin cycle regeneration phase. In our study PdRPE gene was cloned from fast-growing hybrid poplar NE-19 (Populus nigra × (Populus deltoids × Populus nigra)), and then PdRPE was transformed into Arabidopsis thaliana by the floral dip method. Using PCR and Green Fluorescent Protein (GFP) detection methods, we obtained the CaMV35S:PdRPE:GFP transgenic plants. Then we validated the growth status and physiological indexes of wild type (Col-0), overexpressing (OxPdRPE), mutant (rpe) and complementary (rpe/PdRPE) lines. The results indicated that in overexpressing lines RPEase activity increased significantly (P<0.05). When well-watered, the overexpressing lines had lower leaf stomatal density, larger stomatal size, improved water use efficiency and higher net photosynthetic rate, showing a better growth condition and more starch accumulation. When exposed to 10 days of short-term drought, the net photosynthetic rate and water use efficiency of overexpressing lines were still significantly higher than those of the other three strains (P<0.01). Therefore, we reach the conclusion that over-expression of RPEase gene can promote the plant growth and development and enhance the resistance of short-duration drought in Arabidopsis thaliana.