Structures of Lipopolysaccharide Side‐chains of NCPPB 2995, the Neopathotype Strain of Pseudomonas syringae pv. mors‐prunorum and Three Other Strains, in Relation to O‐serogroup

Side‐chains from the lipopolysaccharides (LPSs) of three virulent isolates of Pseudomonas syringae pv. mors‐prunorum all contained D‐rhamnose. Using Smith degradation, 1H‐ and 13C‐nuclear magnetic resonance spectroscopy, methylation analysis, and GC‐MS, the side‐chain of strain CFBP 2115 was shown to consist of the repeat sequence: image NCPPB 2995, the neopathotype strain of P. syringae pv. mors‐prunorum, contained an identical side‐chain, which co‐purified with a glycogen‐like polymer composed of terminal, 1,4,6‐ and 1,4‐linked D‐glucose residues in the ratio 1:1:2.25. The side‐chain of P. syringae pv. mors‐prunorum strain NCPPB 2422 bore the same backbone structure as CFBP 2115, but was substituted by up to 80% with branch D‐fucofuranose residues: image From the pattern of hydrolysis by phage A7 rhamnanase, the tetra and trisaccharide repeat sequences appeared to be irregularly interspersed. The side‐chain from LPS of P. syringae pv. syringae strain C414 was of similar structure, but was only 35% fucosylated. Sidechain structures are correlated with a previously proposed serogrouping system.