TRANSGENIC CORN PLANTS EXPRESSING MDMV STRAIN-B COAT PROTEIN ARE RESISTANT TO MIXED INFECTIONS OF MAIZE-DWARF MOSAIC-VIRUS AND MAIZE CHLOROTIC MOTTLE VIRUS

The maize dwarf mosaic virus strain B (MDMV-B) coat protein (cp) gene was cloned into a monocot expression cassette and introduced into swee t corn cell suspension cultures via particle bombardment or electropor ation. Transformed cells were selected on culture media containing 300 mg/l kanamycin, and plants were regenerated. Cells from all transform ed lines expressed the cp gene; and one transgenic line synthesized ap proximately 100-200 mug MDMV-cp per gram fresh weight. Plants regenera ted from this line were challenged with a virus inoculum concentration adjusted to produce symptoms in nontransgenic controls at six days po st inoculation. In growth chamber studies, the presence of the MDMV-cp provided resistance to inoculations with MDMV-A or MDMV-B and to mixe d inoculations of MDMV and maize chlorotic mottle virus.