Erwinia pyrifoliae is a novel bacterial pathogen, which causes Asian pear blight and is related to Erwinia amylovora, the causative agent of fire blight. E. pyrifoliae produces exopolysaccharide (EPS) related to amylovoran in its sugar composition and sugar linkages. This was shown by degradation of the EPS with a viral depolymerase, and by methylation analysis and ESI/MS. The structure of the repeating units was confirmed by (1)H-NMR spectra. The EPS of E. pyrifoliae carried side chains, which were mainly terminated by acetyl and pyruvyl residues as found previously for amylovoran. On the other hand, a second side chain with glucose found for up to 65% of the repeating units of amylovoran was completely absent. The nucleotide sequences of five genes of the cps cluster of E. pyrifoliae encoding proteins for EPS synthesis were characterized and displayed a high homology with the corresponding ams genes. Similar functions of the gene products are assumed. As for ams mutants of E. amylovora, a cpsB mutant of E. pyrifoliae did not synthesize EPS and did not produce ooze on slices of immature pears or symptoms on pear seedlings. The cps mutant was complemented for EPS synthesis and virulence on pear slices with a gene cluster of E. amylovora that included amsB.

amylovoran, fire blight, Asian pear blight, cps genes, sugar linkage

13C NMR data:
missing...

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

[*]O[C@@H]1[C@@H](O)[C@@H](OC[C@H]2O[C@@H](O[C@@H]3[C@@H](O)[C@H]([*])O[C@H](CO)[C@@H]3O)[C@H](O)[C@@H](O)[C@H]2O)O[C@H](CO)[C@@H]1O[C@@H]1O[C@H](C(=O)O)[C@@H](O[C@H]2O[C@@H]3COC(C)(C(=O)O)O[C@@H]3[C@H](OC(C)=O)[C@H]2OC(C)=O)[C@H](O)[C@H]1O

978.809 g/mol (C₃₇H₅₄R₂O₃₀, R = next and previous repeats, not counted in mol weight)

Erwinia pyrifoliae is a novel bacterial pathogen, which causes Asian pear blight and is related to Erwinia amylovora, the causative agent of fire blight. E. pyrifoliae produces exopolysaccharide (EPS) related to amylovoran in its sugar composition and sugar linkages. This was shown by degradation of the EPS with a viral depolymerase, and by methylation analysis and ESI/MS. The structure of the repeating units was confirmed by (1)H-NMR spectra. The EPS of E. pyrifoliae carried side chains, which were mainly terminated by acetyl and pyruvyl residues as found previously for amylovoran. On the other hand, a second side chain with glucose found for up to 65% of the repeating units of amylovoran was completely absent. The nucleotide sequences of five genes of the cps cluster of E. pyrifoliae encoding proteins for EPS synthesis were characterized and displayed a high homology with the corresponding ams genes. Similar functions of the gene products are assumed. As for ams mutants of E. amylovora, a cpsB mutant of E. pyrifoliae did not synthesize EPS and did not produce ooze on slices of immature pears or symptoms on pear seedlings. The cps mutant was complemented for EPS synthesis and virulence on pear slices with a gene cluster of E. amylovora that included amsB.

amylovoran, fire blight, Asian pear blight, cps genes, sugar linkage

13C NMR data:
missing...

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

[*]O[C@@H]1[C@@H](O)[C@@H](OC[C@H]2O[C@@H](O[C@@H]3[C@@H](O)[C@H]([*])O[C@H](CO)[C@@H]3O)[C@H](O)[C@@H](O)[C@H]2O)O[C@H](CO[C@@H]2O[C@H](CO)[C@@H](O)[C@H](O)[C@H]2O)[C@@H]1O[C@@H]1O[C@H](C(=O)O)[C@@H](O[C@H]2O[C@@H]3COC(C)(C(=O)O)O[C@@H]3[C@H](OC(C)=O)[C@H]2OC(C)=O)[C@H](O)[C@H]1O

1140.95 g/mol (C₄₃H₆₄R₂O₃₅, R = next and previous repeats, not counted in mol weight)