Characterization of Agrobacterium vitis strains isolated from feral Vitis riparia

Agrobacterium vitis was isolated from roots of 41 of 66 feral Vitis riparia vines collected in three different regions of New York State. Two of the r egions were more than 150 km from commercial vineyards. The strains were hi ghly diverse as determined by DNA fingerprinting of the chromosomal region lying between the 16S and 23S rRNA genes. Of 24 strains examined, 15 differ ent fingerprints were generated, and none was identical to fingerprints gen erated by previously identified groups of tumorigenic A. vitis strains. Res ults of physiological tests that were done to characterize strains from V. riparia conformed closely to those expected for A. vitis, except that 23 of 26 strains did not utilize tartrate. All strains were nontumorigenic, did not hybridize with a probe consisting of T-DNA genes, did not utilize octop ine or nopaline, and carried zero to three plasmids. Of 26 strains, 7 inhib ited A. vitis strain K306 from causing galls at wound sites on grape as wel l as or better than a previously studied nontumorigenic A. vitis strain, F2 /5, that is known to have biological control activity.