GENETIC-ANALYSIS OF AGROBACTERIUM-TUMEFACIENS AND A-VITIS USING RANDOMLY AMPLIFIED POLYMORPHIC DNA

The extent of genetic heterogeneity within and between three Agrobacte rium biovars: A, tumefaciens biovars I and II, and A. vitis (biovar II I) was surveyed using randomly amplified polymorphic DNA (RAPD) marker s. 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 ba nds were identified. Biovar II strains exhibited the highest proportio n of shared bands (41%, vs. 38% and 12% for biovar and A. vitis, respe ctively), but only one of these shared markers was intraspecifically m onomorphic. In contrast, biovar I strains had a larger proportion of s hared markers that were intraspecifically monomorphic. The greatest ge netic diversity was detected among the A. vitis genotypes. Although ge netic variation detected between strains was high, phenetic analysis r evealed that genetic similarity was highly correlated with biovar desi gnation. Our results suggest that RAPD markers may have utility in Agr obacterium (biovar) identification and classification.