Agrobacterium-mediated production of transgenic plants from mature embryos of commercial rice varieties

Abstract

Efficient, rapid, and reproducible system has been established for transformation of commercial varieties of rice via Agrobacterium tumefaciens. Calli induced from mature embryos of varieties E-yi 105, E-Wan 5, and Zhong-Shu-Wan-Geng (ZSWG) were cocultivated with the LBA4404 strain carrying the superbinary plasmid pTOK233. The frequency of transient gene expression in infected calli was as high as 100% under optimal conditions. Calli selected on hygromycin (50 mg L-1) medium for 6-8 wk showed uniform uidA gene expression. One hundred mature embryos of E-yi 105, E-Wan 5, and ZSWG yielded 107, 95, and 35 transgenic plantlets, respectively. Most transgenic plants of E-yi 105 reached fertile maturity in a controlled environment cabinet. Leaves, roots, immature embryos, anthers, and endosperm from these transgenic plants expressed the uidA gene. This rice transformation system provides a tool for introducing agronomically important genes into commercial varieties of rice and also offers the possibility of studying the mechanism of T-DNA transfer from A. tumefaciens into cells of monocotyledonous plants