Abstract: Ribulose-1,5-bisphosphate carboxylase/xygenase（Rubisco）is a key enzyme in the photosynthetic carbon cycle. In order to elucidate the activating mechanism of Rubisco in plants，the Rubisco activase gene CsRCA was introduced into inbred line of cucumber with the Agrobacterium-mediated method. The transgenic plants were screened by PCR，and their expression in mRNA and protein level were analysed by real-time PCR and western blot respectively. The restriction enzyme result showed that the CsRCA was inserted into the binary vector pCAMBIA1301，a sense expression vector containing CsRCA gene was constructed. The resulting plasmid was introduced into cucumber inbred lines‘08-1’，and seven transgenic plants which contain two CsRCA copies were obtained（The wild type plants contain one CsRCA copy）. The transformation rate was about 3.5%. The seven T0 transgenic cucumber plants showed 1–1.98 folds in CsRCA mRNA abundance and a significant increase in expression of protein level compared with the wild type（WT）plants. CsRCA over expression led to significant increase in the pigment content，photosynthetic rate（P_n），soluble sugar and starch contents in T1 transgenic plant leaves. These data indicated that stable genetic CsRCA transgenic cucumber plants were obtained with Agrobacterium-mediated method. CsRCA over expression increased the P_n and carbohydrate significantly in cucumber leaves.

Key words: cucumber, Ribulose-1,5-bisphosphate carboxylase/oxygenase（Rubisco）, Rubisco activase（RCA）, genetic transformation, over expression