Cloning And Expressional Characterization Of Soybean GmcpSecA Gene

The Sec-dependent protein sorting pathway is essential for protein import into the thylakoid lumen and is important for the proper function of the chloroplast. We have previously reported the characterization of a loss-of-function mutant of cpSecA, the ATPase subunit of the Sec protein complex. The homozygous mutant is albino and seedling lethal, and lacks the thylakoid structure. We cloned the full-length cDNA of GmcpSecA and its 1.5 kb promoter sequence upstream of the coding region from soybean, and examined the expression patterns of GmcpSecA by RT-PCR in soybean. In this study, We constructed GmcpSecA::GUS and 35S::GmcpSecA fusion genes and introducted into Arabidopsis by Agrobacterium-mediated floral diping. Histochemical staining of GUS revealed that GmcpSecA is strongly expressed in all green tissues including cotyledons, rossette leaves, and sepals whereas no expression could be detected in non-green tissues such as roots, inflorescencs, and siliques.We transformed the agyl mutant with p35S::GmcpSecA, and the results showed that GmcpSecA can partialy restore the phenotype of agyl. Our data indicates that the GmcpSecA gene has a function similar to AtcpSecA, and that GmcpSecA plays an important role in chloroplast biogenesis.Then we transformed the wild-type with p35S::GmcpSecA. Compared with the wild-type, the 35S::GmcpSecA transgenic Arabidopsis growed more vigorously,.The transgenic plants bolted, flowered, and produced seeds earlier compared to wild-type. In addition, the transgenic plants are more sensitive to light than the wild-type.