TRANSFORMATION OF CAULIFLOWER (BRASSICA-OLERACEA VAR BOTRYTIS) BY TRANSFER OF CAULIFLOWER MOSAIC-VIRUS GENES THROUGH COMBINED COCULTIVATIONWITH VIRULENT AND AVIRULENT STRAINS OF AGROBACTERIUM

Cauliflower is known to be recalcitrant to genetic transformation and very few successful transformation experiments have been reported. Tra nsformation of cauliflower was carried out by co-inoculation of in vit ro plants with both a wild type Agrobacterium tumefaciens strain and a disarmed strain containing nptII and hpt genes in addition to the CaM V derived sequence. The capsid gene and the antisense gene VI of cauli flower mosaic virus (CaMV) have been chosen to be transferred into cau liflower genome in order to test their ability to confer resistance to CaMV infection. Transgenic plants were obtained for all the used cons tructions. Transformant screening was performed by histochemical GUS a ssay: 2.13% of regenerating analysed plants displayed GUS activity. Mo lecular characterization of primary transformants was achieved, Integr ation of T-DNA in plant genome was checked in all tested plants and mu ltiple insertions (2-4 copies) were observed. While CaMV gene transcri pts were detected in all plants, the amount of RNA transcribed in plan t cells appeared to be very low in most transgenic plants, which is co ntrary to hpt gene transcripts. In plants transformed with the capsid gene, the capsid protein could not be detected.