Determination of Rhizobium species and heterogeneity of strains causing grapevine crown gall disease by IS50-PCR

Abstract

Crown gall is amongst the most important diseases of grapevine (Vitis vinifera) in many areas where grapevine is grown worldwide. To assess the diversity of Rhizobium species and strains, associated with the crown gall disease of grapevine in the major grapevine growing areas of northern Iran, 105 strains of the suspected bacterium were isolated from tumors of the crown and vines collected from vineyards in East and West Azarbayjan provinces. The strains were characterized by their phenotypic features, presence of virD2 and polygalacturonase genes and comparison of IS50-PCR fingerprints of the strains with those of the reference strains. Ninety two strains amplified a 224 bp fragment of the VirD2 gene in PCR reactions using VirD2A/VirD2C primers. Sixty four strains of Rhizobium (Agrobacterium) could amplify a 466 bp fragment with the primers PGF/PGR were identified as R. vitis. Strains were differentiated into 4 clusters at 55% similarity level of IS50-PCR generated fingerprint patterns. The majority of the strains formed subgroups in R.vitis cluster. Division of each of these two clusters into several subgroups at 80% similarity level reflected existence of a great level of diversity in population of both species.

Keywords

• grapevine
• rhizobium
• polygalacturonase gene
• is50-pcr