Genetic Transformation of Maize Female Inflorescence Following Floral Dip Method Mediated by Agrobacterium

As a simple and high-efficient genetic transformation approach, floral dip method has been widely used for the studies of gene function in Arabidopsis and other plant species. However, there is no report about its applications in maize. In this study, the floral-dip method of transformation by immersed maize female inflorescences in Agrobacterium suspension was firstly applied in the maize transformation. We found that the best transformation period of corn silk size is 5-10 cm and the optimal cell concentration of Agrobacterium transformation is OD600 = 1.0. A large number of green phosphor dots by Green Fluorescent Protein (GFP) were observed in the T0 transformed seeds indicating that the T-DNA-carried gfp gene integrated and expressed in the receipt plant genome. The hygromycin selection and PCR assay of exogenous gene hpt displayed that 3.3% produced plantlet were positive. Therefore, we concluded that the floral dip method mediated by Agrobacterium can be used for the genetic transformation in maize.