Molecular Studies on the Role of a Root Surface Agglutinin in Adherence and Colonization by Pseudomonas putida

Abstract

Pseudomonas putida aggressively colonizes root surfaces and is agglutinated by a root surface glycoprotein. Mutants of P. putida derived chemically or by Tn 5 insertion demonstrated enhanced or decreased agglutinability. Two nonagglutinable Tn 5 mutants (Agg − ) and two mutants with enhanced agglutinability (Agg s ) possessed Tn 5 in unique restriction sites. Agg − mutants colonized root surfaces of seedlings grown from inoculated seeds, but at levels lower than those observed with the Agg + parent. In short-term binding studies, Agg − cells adhered at levels that were 20- to 30-fold less than those for Agg + parental cells. These data suggest that the agglutination interaction plays a role in the attachment of P. putida to root surfaces.