Specificity of strain and genotype in the susceptibility of pea to Agrobacterium tumefaciens.

To determine the best combination for potential use in transformation of Pisum sativum L., 13 genotypes were inoculated with wild-type Agrobacterium tumefaciens strains A281, C58 and Ach5. A281 appeared to be the most virulent strain, as determined by size and number of tumours, followed by C58 and Ach5. Genotypes differed considerably in their response to inoculation and genotype x strain interaction was evident. Genotypes also responded differently to in vivo or in vitro inoculation. Axenic calli from tumours could be grown on hormone-free medium and the presence of the specific opines for each strain in the callus indicated successful transfer and expression of T-DNA. Southern blot analysis of DNA from callus of A281-inoculated material showed that both TR and TL T-DNA had been incorporated into the pea genome.