[Discovery of phytopathogenic bacteria 100 years ago: transatlantic controversies and polemics].

The demonstration of a bacterial cause of some plant diseases has been claimed few years after it was commonly recognized that bacteria were able to cause diseases of human and animal. Nevertheless, some sharp controversies took place, between German and American specialists (1897-1901), before the existence of bacterial diseases of plants was accepted by all phytopathologists. Nowadays, about 350 bacteria are described, which infect plants: they are pathovars, or subspecies, belonging to 21 genera.

Characterization of plasmid-borne and chromosome-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 classification in three phena which exactly matched the delineation of biovars 1, 2, and 3. A fourth phenon was identified which comprises three atypical strains.