Extracellular polysaccharide of Erwinia chrysanthemi Ech6

Many strains of Erwinia chrysanthemi, which are Gram-negative bacterial phytopathogens, produce copious amounts of extracellular polysaccharides. The extracellular polysaccharide from E. chrysanthemi pv. zeae strain SR 260, a phytopathogen of corn, is a branched-chain glucomannorhamnan of proven structure (Gray et al., Carbohydr. Res. 1993, 245, 271–287). The extracellular polysaccharide from E. chrysanthemi Ech6 is different, containing no rhamnose or mannose. It is composed of -fucose, -galactose, -glucose and -glucuronic acid in the ratio 2:2:1:1. The structure of the polysaccharide is as follows:

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