EXPRESSION OF COAT PROTEIN GENE FROM CUCUMBER MOSAIC-VIRUS STRAIN-C IN TOBACCO - PROTECTION AGAINST INFECTIONS BY CMV STRAINS TRANSMITTED MECHANICALLY OR BY APHIDS

The coat protein (CP) gene from cucumber mosaic virus (CMV) strain C was engineered for expression in plants and transferred into the genome of tobacco (Nicotiana tabacum 'Xanthi'). Transfer of the CP gene was confirmed, and plants containing it produced the expected 1,400-nucleotide mRNA and 24-kDa protein products, which were detected by northern and western blots, respectively. Transgenic tobacco plant lines were infected with CMV strains C and Chi of subgroup I and strain WL of subgroup II, transmitted mechanically or by aphids. The effectiveness of the protection varied in different transgenic plant lines, ranging from almost complete protection to none, depending upon the challenge strain. These experiments demonstrate that within a group of transgenic plants expressing the CP gene of CMV strain C (subgroup I), plant lines can be found that show a significant degree of protection when challenged with CMV strains of either subgroup.