Rapid screening for host-bacterium interactions in Agrobacterium-mediated gene transfer to chrysanthemum, by using the GUS-intron gene

Abstract

The susceptibilities to gene transfer of seven genotypes of chrysanthemum ( Dendranthema grandiflora), upon infection of leaf explants with wild-type Agrobacterium strains, were compared in a search for highly efficient cultivar/bacterial strain combinations. Large differences between genotypes were found, but for all genotypes the supervirulent strain A281 was more efficient than the strain Ach5. Early transformation events were monitored using an intron-containing β-glucuronidase (GUS) gene, allowing statistical analysis of the effects of changes in the protocol. Expression of the GUS gene in chrysanthemum was detectable several days later than in tobacco. There was no clear correlation between the size and frequency of tumour formation following infection with wild-type strains of Agrobacterium and transformation efficiency, as determined with the GUS-intron gene. The GUS-intron gene proved useful in the location of preferential gene transfer sites. Cells or cell clusters expressing GUS were mostly found near the edge of the leaf explant.