Optimizing conditions for Agrobacterium-mediated transformation of Chardonnay grape cultivar's embryogenic cells

To establish an efficient transformation of grape(Vitis vinifera),the factors affecting the Agrobacterium-mediated transformation efficiency were studied by GUS assay using the embryogenic cells as the target tissue.The embryogenic cells were sonicated and inoculated with Agrobacterium EHA105/pCAMBIA1301,and placed on co-culture medium containing different concentrations of acetosyringone and dithiothreitol.The transient expression of the gene gus was assayed at 3 or 4 d after co-cultivation for transformation.The highest transformation efficiency was obtained when the embryogenic cells were sonicated for 5 min.The concentration of acetosyringone also affected the transformation efficiency.The average blue spots were determined to be 8.89 at 50 μmol/L AS,and 12.44 at 100 μmol/L AS.The addition of DTT to the co-culture medium also enhanced transient GUS expression.The blue spots were reached up to 16.67 at 3 mg/L of DTT.In this study,the optimum factors affecting the Agrobacterium-mediated transformation of grape embryogenic cells were established by GUS transient expression assay.These results will provide useful information for establishment of an efficient transformation method of grape.