CHARACTERIZATION OF CELL-SURFACE PROPERTIES IN AGGLUTINABLE AND NONAGGLUTINABLE MUTANTS OF PSEUDOMONAS-PUTIDA

Cells of an aggressive, root-colonizing isolate of Pseudomonas putida are agglutinated by a root surface glycoprotein. The agglutination phe notype in P. putida isolate Corvallis is lacking in mutants (Agg -) de rived by Tn5 insertion and chemical mutagenesis. Specific mutation in the aggA locus by Tn5 insertion results in loss of agglutinability tha t is complemented in trans by a wild-type copy of the P. putida aggA l ocus. We examined the biochemical bases of agglutination in P. putida by comparing cell surface features in Agg+, Agg - mutants, and a genet ically restored aggA mutant. No changes in gross cell surface features involving hydrophobic or hydrophilic binding or net negative charge w ere observed. Three macromolecular features, pili, flagella, and lipop olysaccharide size, did not differ between Agg+ and Agg - mutants. Pro tein profiles of cell envelope, periplasmic, and outer membrane prepar ations revealed pleiotropic effects of mutation in agglutination pheno type including alterations of an outer membrane protein of 47 000 mole cular weight and periplasmic proteins of 56 000 and 60 000 molecular w eight. The protein alterations seen in the aggA::Tn5 Agg - mutant 5123 reverted to wild-type patterns upon introduction of a wild-type copy of the aggA locus. These data suggest agglutinability may be condition ed by more than one proteinaceous component associated with the bacter ial envelope layers.