Characterization of plasmid-borne and chrome some-encoded traits of Agrobacterium biovar 1, 2, and 3 strains from France

We collected 111 Agrobacterium isolates from galls of various origins (most of them from France) and analyzed both their plasmid-borne and chromosome- encoded traits. Phenotypic analysis of these strains allowed their classifi cation in three phena which exactly matched the delineation of biovars 1, 2 , and 3. A fourth phenon was identified which comprises three atypical stra ins. The phenotypic analysis has also allowed us to identify 12 additional characteristics which could be used to identify the three biovars of Agroba cterium, Our results also suggest that biovar 1 and 2 represent distinct sp ecies. Analysis of plasmid-borne traits confirmed that tartrate utilization is a common feature of biovar 3 strains (now named Agrobacterium vitis) an d of Agrobacterium grapevine strains in general. Among pathogenic strains o f Agrobacterium, several exhibited unusual opine synthesis and degradation patterns, and one strain of biovar 3 induced tumors containing vitopine and a novel opine-like molecule derived from putrescine. We have named this co mpound rideopine.