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Haemagglutinins and fimbriae of soft rot Erwinias
1Department of Mycology and Bacteriology, Scottish Crop Research Institute, Dundee, UK.
Abstract:
Strains of phytopathogenic soft rot Erwinia spp. were examined for haemagglutinin (HA) production. Mannose-sensitive HA was found only in five of 15 strains of E. carotovora subsp. carotovora. Mannose-resistant HA (MRHA) was found in 12 of 15 strains of E.c. carotovora, ten of 13 strains of E.c. subsp. atroseptica and the single strain of E.c. subsp. betavasculorum, as well as all seven strains of E. chrysanthemi. MRHA, detectable only in a microtitre tray HA assay was of either broad- or narrow-spectrum activity when examined against blood of seven different animal species and could be inhibited by the beta-galactoside asialofetuin. Fimbriae of ca 10 nm diameter were found on MRHA(+) bacteria E.c. carotovora and E.c. atroseptica.
Insights
This study investigated haemagglutinin (HA) production in soft rot Erwinia species. Mannose-resistant HA (MRHA) was prevalent across multiple strains, suggesting its potential role in pathogenicity.
Area of Science:
- Microbiology
- Plant Pathology
- Bacteriology
Background:
- Erwinia species are significant phytopathogens causing soft rot diseases.
- Haemagglutinins (HAs) are surface proteins implicated in bacterial adhesion and virulence.
- Understanding HA production in Erwinia is crucial for disease management.
Purpose of the Study:
- To characterize haemagglutinin (HA) production in various strains of phytopathogenic soft rot Erwinia species.
- To determine the prevalence and characteristics of mannose-sensitive HA and mannose-resistant HA (MRHA).
- To investigate the potential association of MRHA with fimbriae and its activity spectrum.
Main Methods:
- Screening of Erwinia strains for haemagglutinin (HA) production using microtitre tray assays.
- Testing HA sensitivity to mannose and inhibition by asialofetuin.
- Examination of bacterial surface structures using electron microscopy (implied by fimbriae observation).
- Assessing MRHA activity against erythrocytes from different animal species.
Main Results:
- Mannose-sensitive HA was detected in a limited number of E. carotovora subsp. carotovora strains.
- Mannose-resistant HA (MRHA) was widely distributed among E. carotovora subsp. carotovora, E. carotovora subsp. atroseptica, E. carotovora subsp. betavasculorum, and E. chrysanthemi.
- MRHA exhibited broad- or narrow-spectrum activity and was inhibited by asialofetuin.
- Fimbriae approximately 10 nm in diameter were observed on MRHA-positive E. carotovora strains.
Conclusions:
- Mannose-resistant HA (MRHA) is a common characteristic of phytopathogenic soft rot Erwinia species.
- The presence of fimbriae in MRHA-positive strains suggests their involvement in MRHA-mediated adhesion.
- MRHA's broad-spectrum activity and inhibition by asialofetuin indicate its potential role in Erwinia pathogenesis and host interactions.