Editor: Yaacov Okon
Characterization of cell surface and extracellular matrix remodeling of Azospirillum brasilense chemotaxis-like 1 signal transduction pathway mutants by atomic force microscopy
Article first published online: 24 NOV 2010
FEMS Microbiology Letters © 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. No claim to original US government works
FEMS Microbiology Letters
Volume 314, Issue 2, pages 131–139, January 2011
How to Cite
Edwards, A. N., Siuti, P., Bible, A. N., Alexandre, G., Retterer, S. T., Doktycz, M. J. and Morrell-Falvey, J. L. (2011), Characterization of cell surface and extracellular matrix remodeling of Azospirillum brasilense chemotaxis-like 1 signal transduction pathway mutants by atomic force microscopy. FEMS Microbiology Letters, 314: 131–139. doi: 10.1111/j.1574-6968.2010.02156.x
- Issue published online: 16 DEC 2010
- Article first published online: 24 NOV 2010
- Accepted manuscript online: 8 NOV 2010 09:19AM EST
- Received 18 October 2010; accepted 24 October 2010.Final version published online 24 November 2010.
- Azospirillum brasilense;
To compete in complex microbial communities, bacteria must sense environmental changes and adjust cellular functions for optimal growth. Chemotaxis-like signal transduction pathways are implicated in the regulation of multiple behaviors in response to changes in the environment, including motility patterns, exopolysaccharide production, and cell-to-cell interactions. In Azospirillum brasilense, cell surface properties, including exopolysaccharide production, are thought to play a direct role in promoting flocculation. Recently, the Che1 chemotaxis-like pathway from A. brasilense was shown to modulate flocculation, suggesting an associated modulation of cell surface properties. Using atomic force microscopy, distinct changes in the surface morphology of flocculating A. brasilense Che1 mutant strains were detected. Whereas the wild-type strain produces a smooth mucosal extracellular matrix after 24 h, the flocculating Che1 mutant strains produce distinctive extracellular fibril structures. Further analyses using flocculation inhibition, lectin-binding assays, and comparison of lipopolysaccharides profiles suggest that the extracellular matrix differs between the cheA1 and the cheY1 mutants, despite an apparent similarity in the macroscopic floc structures. Collectively, these data indicate that disruption of the Che1 pathway is correlated with distinctive changes in the extracellular matrix, which likely result from changes in surface polysaccharides structure and/or composition.