LIPOPOLYSACCHARIDES FROM 3 PHYTOPATHOGENIC PSEUDOMONADS

Analysis of the polysaccharide and lipid moieties of the lipopolysacch arides (LPSs) of the phytopathogenic bacteria, Pseudomonas amygdali an d P. syringae pv. ciccaronei has demonstrated that for both bacteria t he O-chain consists of a tetrasaccharide repeating unit of three alpha -L-Rhap and one terminal nonreducing alpha-D-Fucp3NAc. Two of the rham nosyl residues are 3-linked, the third one 2,3-linked. This structure had been previously found for the O-chains of three phytopathogenic st rains of P. syringae subsp. savastanoi, but this is the first report o n its occurrence in P. amygdali and P. syringae pv. ciccaronei. The re sults of the LPS lipid residue analysis made it possible to make some chemotaxonomic considerations and therefore classify P. amygdali as a chemotype, which is different from that of the other two bacteria exam ined. (C) 1997 Elsevier Science Ltd.