AlgW regulates multiple Pseudomonas syringae virulence strategies.
Karl J Schreiber1, Darrell Desveaux
1Department of Cell & Systems Biology, University of Toronto, Toronto, ON M5S 3B2, Canada.
Molecular Microbiology
|February 11, 2011
Summary
Pseudomonas syringae uses AlgW to suppress plant immunity by coordinating virulence strategies. This protease regulates flagellin, alginate, and type III secretion, dampening host immune responses for effective infection.
Area of Science:
- Microbiology
- Plant Pathology
- Molecular Biology
Background:
- Gram-negative bacterial pathogens employ virulence factors like alginate and effector proteins.
- Induction of virulence mechanisms often correlates with reduced immune-triggering proteins, such as flagellin.
- In Pseudomonas syringae, motility and flagellin abundance decrease when the type III secretion system is induced.
Purpose of the Study:
- To identify genes regulating the negative correlation between type III secretion system induction and flagellin abundance in Pseudomonas syringae.
- To investigate the role of identified regulators in coordinating bacterial virulence strategies and suppressing plant immune responses.
Main Methods:
- Forward genetic screen using motility as a phenotype in P. syringae pv. maculicola ES4326.
- Analysis of gene regulation affecting flagellin abundance, alginate biosynthesis, and type III secretion.
- Assessment of AlgW's role as a virulence determinant in P. syringae.
Main Results:
- The periplasmic protease AlgW was identified as a key negative regulator of flagellin abundance.
- AlgW positively regulates alginate biosynthesis and the type III secretion system.
- AlgW is a crucial virulence determinant for P. syringae, suppressing plant immune responses.
Conclusions:
- P. syringae coordinates virulence strategies through AlgW to effectively suppress host immunity.
- AlgW plays a central role in balancing bacterial virulence factor production and immune evasion.
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