Adhesion of the entomopathogenic fungus Beauveria (Cordyceps) bassiana to substrata - PubMed (original) (raw)
Adhesion of the entomopathogenic fungus Beauveria (Cordyceps) bassiana to substrata
Diane J Holder et al. Appl Environ Microbiol. 2005 Sep.
Abstract
The entomopathogenic fungus Beauveria bassiana produces at least three distinct single-cell propagules, aerial conidia, vegetative cells termed blastospores, and submerged conidia, which can be isolated from agar plates, from rich broth liquid cultures, and under nutrient limitation conditions in submerged cultures, respectively. Fluorescently labeled fungal cells were used to quantify the kinetics of adhesion of these cell types to surfaces having various hydrophobic or hydrophilic properties. Aerial conidia adhered poorly to weakly polar surfaces and rapidly to both hydrophobic and hydrophilic surfaces but could be readily washed off the latter surfaces. In contrast, blastospores bound poorly to hydrophobic surfaces, forming small aggregates, bound rapidly to hydrophilic surfaces, and required a longer incubation time to bind to weakly polar surfaces than to hydrophilic surfaces. Submerged conidia displayed the broadest binding specificity, adhering to hydrophobic, weakly polar, and hydrophilic surfaces. The adhesion of the B. bassiana cell types also differed in sensitivity to glycosidase and protease treatments, pH, and addition of various carbohydrate competitors and detergents. The outer cell wall layer of aerial conidia contained sodium dodecyl sulfate-insoluble, trifluoroacetic acid-soluble proteins (presumably hydrophobins) that were not present on either blastospores or submerged conidia. The variations in the cell surface properties leading to the different adhesion qualities of B. bassiana aerial conidia, blastospores, and submerged conidia could lead to rational design decisions for improving the efficacy and possibly the specificity of entomopathogenic fungi for host targets.
Figures
FIG. 1.
Saturation points of sites for binding of B. bassiana aerial conidia (•), blastospores (▪), and submerged conidia (○) to microtiter plates. The error bars indicate the results of at least three independent experiments.
FIG. 2.
Quantitative adhesion and influence of washing on adhesion of aerial conidia (A), blastospores (B), and submerged conidia (C) to silinated F200 (hydrophobic), F200 (weakly polar), and F600 (hydrophilic) microtiter plates. The percentages of cells bound after one wash (open bars) and after three washes (solid bars) are presented versus assay incubation time. The error bars indicate the results of at least three independent experiments.
FIG. 3.
Analysis of SDS-insoluble trifluoroacetic acid-soluble material from ultrasonic extracts of B. bassiana aerial conidia, blastospores, and microcycle conidia. An SDS-PAGE gel (10% polyacrylamide, bis-Tris) was stained with Coomassie blue. Lane 1, protein molecular weight standards; lane 2, aerial conidia; lane 3, blastospores; lane 4, submerged conidia.
References
- Bird, A. F., and A. C. McKay. 1987. Adhesion of conidia of the fungus Dilophosphora alopecuri to the cuticle of the nematode Anguina agrostes, the vector in annual ryegrass toxicity. Int. J. Parasitol. 17**:**1239-1247.
- Boucias, D., and J. Pendland. 1991. Attachment of mycopathogens to cuticle, p. 101-127. In G. T. Cole and H. C. Hoch (ed.), The fungal spore and disease initiation in plants and animals. Plenum Press, New York, N.Y.
- Broome, J. R., P. P. Sikorowski, and B. R. Norment. 1976. A mechanism of pathogenicity of Beauveria bassiana on larvae of the imported fire ant, Solenopsis richteri. J. Invertebr. Pathol. 28**:**87-91. -PubMed
- Brownbridge, M., S. Costa, and S. T. Jaronski. 2001. Effects of in vitro passage of Beauveria bassiana on virulence to Bemisia argentifolii. J. Invertebr. Pathol. 77**:**280-283. -PubMed
Publication types
MeSH terms
Substances
LinkOut - more resources
Full Text Sources