Susceptibility of Vigna sesquipedalis Koern (Asparagus bean) to an oncogenic strain of Agrobacterium tumefaciens

A transformation procedure was developed to determine the susceptibility of the grain legume Vigna sesquipedalis Koern to infection by an oncogenic st rain of Agrobacterium tumefaciens. Cotyledonary node explants were prepared from 8-day-old seedlings germinated on B5 basal medium and transformed usi ng oncogenic strain A281 carrying the binary vector PIBGUS-INT with the pat gene and npt II gene as selectable markers and the gus gene as a reporter gene. About 90% of the infected plants showed tumour formation at the cut e nds. The transgenic nature of the tumour was confirmed by GUS' test and Sou thern analysis. some axillary meristems at the nodal region developed into shoots and later into abnormal plants. Histochemical analysis of beta-glucu ronidase gene expression revealed high competence of the subepidermal cell layers of the cotyledonary node to transformation by Agrobacterium.