Articles
CHARACTERIZATION OF A NEW ERWINIA SPECIES AFFECTING ASIAN PEAR TREES
Article number
489_31
Pages
201 – 208
Language
Abstract
Bacteria causing symptoms which resembled fire blight were consistently isolated from necrotic branches of Asian pear fruit trees (Pyrus pyrifolia Nakai) in Korea.
Isolated bacteria were studied in a series of microbiological, pathological and molecular assays.
Serological and BIOLOG assays show a relationship of the novel pathogen to E. amylovora but differences to Enterobacter pyrinus also isolated from Asian pear trees in Korea.
In general, colony morphology on MM2Cu agar was mucoid as for E. amylovora but only slightly yellow.
Its EPS capsules were stained by lectin from Abrus precatorius, specific for amylovoran and degraded by the E. amylovora-specific phage
-Ealh, which cleaves amylovoran in a defined position of the sugar backbone.
Sugar linkage analysis revealed identity with the repeating units of amylovoran.
The new Asian pathogen produced ooze on pear slices and necrotic symptoms on pear seedlings.
From a chromosomal region with high homology to amsB of E. amylovora, a DNA fragment was cloned by PCR and sequenced.
The deduced amino acid of the ORF had 95% homology to AmsB. Site-specific mutants created in this gene were unable to form ooze on pear slices and lost virulence for pear seedlings.
PCR assays with primers from plasmid pEa29 or from the ams-region of E. amylovora were negative for the novel pathogen due to different plasmids in both species.
Dendrograms from Biotype 100 tests displayed a distance between the novel pathogen and E. amylovora. Moreover, the 16S/23S rRNA intergenic transcribed spacer regions (ITS) were divergent.
Macrorestriction and subsequent PFGE analysis produced patterns entirely different from E. amylovora. Two sets of primers did not cross-react with E. amylovora and could be used for detection of the novel pathogen, which has been named Erwinia pyrifoliae according to its host Pyrus pyrifolia.
Isolated bacteria were studied in a series of microbiological, pathological and molecular assays.
Serological and BIOLOG assays show a relationship of the novel pathogen to E. amylovora but differences to Enterobacter pyrinus also isolated from Asian pear trees in Korea.
In general, colony morphology on MM2Cu agar was mucoid as for E. amylovora but only slightly yellow.
Its EPS capsules were stained by lectin from Abrus precatorius, specific for amylovoran and degraded by the E. amylovora-specific phage
-Ealh, which cleaves amylovoran in a defined position of the sugar backbone.Sugar linkage analysis revealed identity with the repeating units of amylovoran.
The new Asian pathogen produced ooze on pear slices and necrotic symptoms on pear seedlings.
From a chromosomal region with high homology to amsB of E. amylovora, a DNA fragment was cloned by PCR and sequenced.
The deduced amino acid of the ORF had 95% homology to AmsB. Site-specific mutants created in this gene were unable to form ooze on pear slices and lost virulence for pear seedlings.
PCR assays with primers from plasmid pEa29 or from the ams-region of E. amylovora were negative for the novel pathogen due to different plasmids in both species.
Dendrograms from Biotype 100 tests displayed a distance between the novel pathogen and E. amylovora. Moreover, the 16S/23S rRNA intergenic transcribed spacer regions (ITS) were divergent.
Macrorestriction and subsequent PFGE analysis produced patterns entirely different from E. amylovora. Two sets of primers did not cross-react with E. amylovora and could be used for detection of the novel pathogen, which has been named Erwinia pyrifoliae according to its host Pyrus pyrifolia.
Publication
Authors
W.-S. Kim, S. Jock, K. Geider, B. Völksch, S.-L. Rhim, J.-P. Paulin, L. Gardan
Keywords
Erwinia pyrifoliae, pathogenicity, rDNA sequencing, differentiation from E. amylovora
Online Articles (121)