Related Experiment Videos
Alginate production by plant-pathogenic pseudomonads
W F Fett1, S F Osman, M L Fishman
1Eastern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Philadelphia, Pennsylvania 19118.
Applied and Environmental Microbiology
|September 1, 1986
Summary
Certain fluorescent plant-pathogenic pseudomonads can produce alginic acid (alginate), a key exopolysaccharide. This finding suggests a broader capability within this bacterial group.
Area of Science:
- Microbiology
- Plant Pathology
- Bacterial Physiology
Background:
- Pseudomonads are a diverse group of bacteria, some of which are significant plant pathogens.
- Alginic acid (alginate) is an exopolysaccharide with various biological roles, but its production by pseudomonads is not fully characterized.
- Understanding alginate production in plant-pathogenic pseudomonads is crucial for disease mechanism studies.
Purpose of the Study:
- To investigate the in vitro alginate production capabilities of various plant-pathogenic and non-pathogenic pseudomonad strains.
- To characterize the properties of alginates produced by these bacteria.
- To assess the biological activity of produced alginates and polyfructans in soybean tissues.
Main Methods:
- Culturing of 18 plant-pathogenic and 3 non-plant-pathogenic pseudomonad strains in vitro.
- Testing alginate production using different carbon sources (glucose, gluconate, sucrose).
- Characterization of alginate composition (guluronic acid content, acetylation) and molecular weight; assessment of phytoalexin elicitation and water-soaking responses in soybean.
Main Results:
- Alginate production was confirmed in 10 of 13 fluorescent plant-pathogenic pseudomonads using glucose or gluconate.
- Nonfluorescent plant pathogens and non-pathogenic strains showed limited or no alginate production.
- Sucrose supported alginate production in some strains, while others produced both alginate and polyfructan (levan).
- Produced alginates varied in guluronic acid content and molecular weight and were acetylated.
- Neither polyfructans nor alginates elicited glyceollin or induced prolonged water soaking in soybean tissues.
Conclusions:
- Fluorescent plant-pathogenic pseudomonads, particularly those in rRNA-DNA homology group I, are likely capable of synthesizing alginate.
- Alginate production is strain- and carbon source-dependent.
- The characterized alginates and polyfructans do not appear to directly induce defense responses like glyceollin elicitation or water soaking in soybean.