VIRUS RESISTANCE OF TRANSGENIC TOBACCO PLANTS EXPRESSING TOBACCO MOSAIC VIRUS COAT PROTEIN GENE

An intermediate expressing vector carrying the tobacco mosaic virus (TMV, Chinese common strain) coat protein (CP) gene was constructed by recombinant DNA techniques. The TMV-CP gene was transferred into the tobacco genome via Ti plasmid and a large number of regenerated plants, including both systemic and local lesion hosts for TMV, were obtained. Southern blot analysis revealed that 1-5 copies of the CP gene were integrated into the tobacco genome. RNA and protein analysis demonstrated that the TMV-CP gene was correctly expressed in the transgenic plants. The abundance of TMV-CP mRNA in total leaf RNA accounted for 0.005-0.01%, while the amount of coat proteins reached 0.05-0.2% of the total leaf soluble proteins. Virus challenge experiments showed that the symptom development of virus infection was markedly delayed and the replication as well as the spread of the virus was significantly inhibited in the transgenic plants expressing the TMV-CP gene. Three of these plants were completely protected afte

VIRUS RESISTANCE OF TRANSGENIC TOBACCO PLANTS EXPRESSING TOBACCO MOSAIC VIRUS COAT PROTEIN GENE

An intermediate expressing vector carrying the tobacco mosaic virus (TMV, Chinese common strain) coat protein (CP) gene was constructed by recombinant DNA techniques. The TMV-CP gene was transferred into the tobacco genome via Ti plasmid and a large number of regenerated plants, including both systemic and local lesion hosts for TMV, were obtained. Southern blot analysis revealed that 1-5 copies of the CP gene were integrated into the tobacco genome. RNA and protein analysis demonstrated that the TMV-CP gene was correctly expressed in the transgenic plants. The abundance of TMV-CP mRNA in total leaf RNA accounted for 0.005-0.01%, while the amount of coat proteins reached 0.05-0.2% of the total leaf soluble proteins. Virus challenge experiments showed that the symptom development of virus infection was markedly delayed and the replication as well as the spread of the virus was significantly inhibited in the transgenic plants expressing the TMV-CP gene. Three of these plants were completely protected after inoculation and they went to flowering and seeding normally. The possible mechanism of this kind of virus resistance could be the inhibition of the uncoating of the invading virus particles at the early stage of infection in the presence of the viral coat protein in plant cells, thus blocking the virus replication cycle.