The Role of Bacterial Motility, Chemotaxis, and Attachment in Bacteria-Plant Interactions. Ann Vande Broek . F. A. Janssens Laboratory of Genetics, W. De Croylaan 42, B-3001 Heverlee, Belgium. Jos Vanderleyden. F. A. Janssens Laboratory of Genetics, W. De Croylaan 42, B-3001 Heverlee, Belgium. MPMI 8:800-810. Accepted 24 July 1995. 1995 The American Phytopathological Society.

Soil bacteria that interact with plants largely differ in the effects that they exert on their host plant. The association between Rhizobium, Azospirillum, or many pseudomonads and their host plant(s) is beneficial for plant growth while the interaction of Agrobacterium with its host is pathogenic and results in plant disease. Despite these differences, it seems that, at least in some cases, common mechanisms are involved in the initial phases of the interaction processes.