Genetic diversity of Agrobacterium vitis from diverse geographic origins based on RAPD and recA gene sequence analysis.

Agrobacterium vitis is a primary causal agent of grapevine crown gall worldwide. Major mode of the pathogen long distance dispersal is via grapevine propagating material. The aim of this study was to assess genetic diversity and phylogenetic relatedness of 62 tumorigenic strains of A. vitis originating from eight European countries (58 strains), North America (2 strains), Australia (1 strain) and North Africa (1 strain). Initial evaluation of genetic diversity among strains was determined by RAPD using three primers: A9, A10 and R13. Genetic profiles were transformed into a binary matrix used for phylogenetic analysis and construction of the dendrogram. The strains were differentiated into 12 genetic groups at 80% similarity level. A total of 27 representative strains, at least one per each RAPD group, were selected for amplification and sequencing of recA housekeeping gene using primers recAF1/recAR1 designed to amplify 615 bp DNA fragment. The sequence similarities among the strains were 92.1-100%. Four clusters were identified in the maximum likelihood phylogenetic tree. The correlation between the genetic groups and geographical origin of the strains was not determined. Geno-typic relatedness of the strains belonging to a particular phylogenetic group indicates that they may have common origin and were probably distributed worldwide following the movement of infected grapevine planting material.