Transformed Plants Producing Opines Specifically Promote Growth of Opine-Degrading Agrobacteria. Pierre Guyon. Institut de Microbiologie, Faculté des Sciences, F-91405 Orsay Cedex, Laboratoire de Biologie Cellulaire, Centre National de la Recherche Agronomique, Versailles Cedex, France.. Annik Petit(1,3), Jacques Tempé(1,3), and Yves Dessaux(1,3). (1)Institut de Microbiologie, Faculté des Sciences, F-91405 Orsay Cedex, and (3)Institut des Sciences Végétales, Centre National de la Recherche Scientifique, Gif-sur-Yvette, France.. MPMI 6:92-98. Accepted 22 October 1992. Copyright 1993 The American Phytopathological Society.

To investigate the effect of plant transformation on opine catabolic (and pathogenic) Agrobacterium, we designed an experimental model in which the changes of a bacterial population associated with the root system of plants could be easily monitored. The bacterial population was composed of opine catabolic and noncatabolic strains of Agro-bacterium. Bacteria were cocultivated with either transformed or normal Lotus plants. The composition of the bacterial population was estimated by dilution and plating of the growth medium on various media. We demonstrated that growth of bacteria was stimulated when they were associated with transformed plants. Furthermore, growth of opine-utilizing bacteria was specifically favored when bacteria were associated with transformed plants, but not when bacteria were associated with normal plants. This work indicates that transformation of plant cells by agro-bacteria indeed can favor growth of the catabolic strain. This finding may lead to creation of engineered plant-bacteria interactions in which both partners will benefit from their association.