Disease symptoms in transgenic tobacco induced by integrated gene VI of cauliflower mosaic virus

A chimeric vector (pKR 612B1) containing the neomycin phosphotransferase (APH) gene from the Tn5 transposon under the control of the gene VI promoter of cauliflower mosaic virus (CaMV) and the cloned gene VI region (SalI-BstEII) of the same virus were used to cotransform tobacco protoplasts. Using the polyethylene glycol transformation procedure, a large number of protoplasts were transformed and proved to be resistant to kanamycin (Km). Whole Km-resistant plants were regenerated and shown to contain the integrated foreign genes. DNA from transformed clones was analyzed by Southern blot hybridization, showing the presence of the Tn5-derived gene and the viral gene. Transgenic plants containing the viral gene show mild mosaic patterns and fasciation. The expression of the gene VI product was detected by immunoblots.