EARLY EVENTS IN TRANSFORMATION OF POTATO BY AGROBACTERIUM-TUMEFACIENS

We have used an intron containing beta-glucuronidase gene to monitor transformation events after Agrobacterium tumefaciens cocultivation with leaf explants of potato. We find that the number of transformation events greatly exceeds the number of transformed plants which can be regenerated, and that some explants have many transformed foci while a significant number have none. Cultivar differences in gene transfer are apparent, and frequencies of gene transfer can be improved with acetosyringone and silver thiosulphate. We also show that, with the transformation vector we used, some Agrobacterium tumefaciens virulence plasmids are more efficient than others.