Efficacy of different Agrobacterium tumefaciens strains in transformation of pinaceous gymnosperms

Abstract The ability of a series of wild-type and transconjugant Agrobacterium tumefaciens and Agrobacterium rhizogenes strains to incite galls on four pinaceous gymnosperm hosts was determined. The hosts were Pseudotsuga menziesii, Pinus ponderosa, Tsuga heterophylla , and Abies procera . Transformation was confirmed by identification of gall opines. The frequency with which galls were incited depended upon the identity of the infecting strain and the identity of the host. Several strains were highly virulent on all hosts. With one exception, an agropine strain, these strains harboured nopaline Ti plasmids. Restriction enzyme digestion and gel electrophoresis of a set of nopaline Ti plasmids from among the highly virulent strains showed that they differed significantly from each other. Such strains may serve as a basis for the construction of efficient vectors for gymnosperm transformation.