CORESTA Meeting, Agronomy/Phytopathology, Oxford, 1995

TMV resistance of the tobacco plant transformed with TMV coat protein cDNA

Korea Ginseng and Tobacco Research Institute, Daejon, South Korea.
TMV-resistant tobacco plants were selected from transformed tobacco containing TMV coat protein (CP) cDNA. The TMV CP cDNA was cloned in HindIII and PstI site of pBluescript II Ks+ plasmid and named pBT1.3. The DraI and SacI fragment of pBT1.3 was cloned in SmaI and SstI site of pBI121 plasmid and named pSK101. The 3' region of cloned TMV cDNA was 434 bps in length and the recombined pSK101 plasmid was transformed to Agrobacterium tumefaciens LBA4404. By using A. tumefaciens LBA4404 containing pSK101 plasmid, tobacco ( Nicotiana tabacum var. NC82) leaf tissue was transformed and tobacco plants were regenerated. The TMV common strain isolated from tobacco in Korea was inoculated to the transgenic tobacco plants for screening TMV resistance. The genetic analysis of transgenic tobacco plants were investigated by Southern and Western blot hybridization. The introduced TMV cDNA was detected in transgenic tobacco plant and the introduced cDNA was expressed to coat protein. The level of expressed coat protein was very low compared to TMV infected tobacco plant. Some transgenic plants of the first generation showed delay type of TMV symptom development. In the second generation, no detectable symptoms were produced in most plants which were from a transgenic plant with the most delayed symptom appearance. When the naked TMV RNA was inoculated to transgenic tobacco plant the high resistance to TMV RNA was also showed. The transgenic tobacco plant also showed resistance to CMV and PVY in high and low frequencies, respectively.