The disease crown gall, which causes damage on perennial agricultural crops, is economically important in many countries. We therefore explored the presence of Agrobacterium spp. in a variety of agricultural soils where fruit trees are grown. Most samples were collected in four regions of Slovenia where a majority of fruit tree plantations are situated. Crown gall-affected plants were not observed on any of the sampling sites. Members of Agrobacterium spp. biovar 1 were isolated from 63 of the 72 soil samples (88%), but none from forest soil. All isolates of this Agrobacterium species complex were determined to be non-pathogenic by biotests and were assigned to genomic species based on a recA allele sequence analysis. Fourty-three isolates were allocated into genomic species G1 and 26 isolates into G4. Among both genomic species, new alleles of the recA gene were recognized: seven new alleles in G1 (denominated G1-15 to G1-21) and four in G4 (G4-7 to G4-10). Two alleles predominated among the Slovenian strains, recA-G1-15 and recA-G4-2. Different colony morphologies were observed between strains of G1 and G4 on KB medium.
crown gall; recA; genomic species