TRANSFORMATION OF THE WILD TOMATO LYCOPERSICON CHILENSE DUN BY AGROBACTERIUM-TUMEFACIENS

Leaf disc transformation-regeneration technique was applied to the drought tolerant wild relative of cultivated tomato, Lycopersicon chilense, using a plasmid construct which contained the coding sequences of neomycin phosphotransferase (NPTII) and chloramphenicol acetyltransferase (CAT) genes. The two genotypes used, LA2747 and LA1930, showed a distinct difference in their aptitude to transformation; a higher success rate was obtained for the first genotype in every stage of the process. Shoots were formed on the regeneration medium containing 100 mu g/ml kanamycin through direct or indirect organogenesis. Root formation became only possible when the concentration of kanamycin was reduced to 50 mu g/ml. Expression of chloramphenicol acetyltransferase gene was observed in all of the kanamycin-screened plants after they matured; the activity of the gene was absent or low in some of the young plants. The presence of the CAT gene in transgenic plants was further confirmed by Southern blot analysis. Although transgenic plants grew to maturity, they did not produce fruit, owing to the self incompatibility of L. chilense.