Purification and composition of lipopolysaccharides from Pseudomonas syringae pv. glycinea

Purified lipopolysaccharides (LPS) from four races of Pseudomonas syringae pv. glycinea were assayed for phytoalexin elicitor activity in soybean cotyledons, and isolated O-chain fractions were chemically characterized. The LPS were weak elicitors of glyceollin accumulation, but no race specificity was noted. SDS-Polyacrylamide gel electrophoresis showed considerable size heterogeneity in the LPS but only slight differences were noted between preparations from the various races. The major components of the O-chain fractions from all races were rhamnose and N-acetylglucosamine. The ratio of these components in preparations from race 4 differed significantly from those of races 1, 5 and 6.