Interaction of Pseudomonas solanacearum with Suspension-Cultured Tobacco Cells and Tobacco Leaf Cell Walls In Vitro.

Attachment of radiolabeled Pseudomonas solanacearum cells to suspension-cultured tobacco cells and tobacco leaf cell walls was measured in vitro by a filtration technique that allowed separation of attached and unattached bacteria. An avirulent strain (B1) attached more rapidly to suspension-cultured cells than did the virulent parent strain (K60), and B1 attachment was less sensitive to inhibition by high ionic strength than was K60. Attachment of B1 bacteria to suspension-cultured cells and to leaf cell walls was comparable (50 to 70%), but only a small proportion (10 to 20%) of K60 bacteria attached to leaf cell walls under optimal conditions. With high bacterial populations (10 bacteria per ml), attachment of K60 to suspension-cultured cells was greatly reduced. Attachment of both strains was completely inhibited by pretreating bacterial cells with heat (41 degrees C) or azide and was partially inhibited by EDTA and kanamycin. The mechanism of attachment is not known, but ionic forces may be involved.