Genetic Analysis of Agrobacterium tumefaciens and A. vitis Using Randomly Amplified Polymorphic DNA

¹ E. & J. Gallo Winery, Box 1130, Modesto, California, 95353
² Department of Viticulture and Enology, University of California, Davis, California, 95616.

The extent of genetic heterogeneity within and between three Agrobacterium biovars: A. tumefaciens biovars I and II, and A. vitis (biovar III) was surveyed using randomly amplified polymorphic DNA (RAPD) markers. A high level of both inter- and intraspecific genetic diversity was detected in the 20 Agrobacterium strains tested. No monomorphic bands were detected and only a small number of intraspecific monomorphic bands were identified. Biovar II strains exhibited the highest proportion of shared bands (41%, vs. 38% and 12% for biovar I and A. vitis, respectively), but only one of these shared markers was intraspecifically monomorphic. In contrast, biovar I strains had a larger proportion of shared markers that were intraspecifically monomorphic. The greatest genetic diversity was detected among the A. vitis genotypes. Although genetic variation detected between strains was high, phenetic analysis revealed that genetic similarity was highly correlated with biovar designation. Our results suggest that RAPD markers may have utility in Agrobacterium (biovar) identification and classification.

Key words: DNA fingerprinting, crown gall, PCR

Submitted on July 21, 1995