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Chitin induces natural competence in Vibrio cholerae
Karin L Meibom1, Melanie Blokesch, Nadia A Dolganov
1Division of Infectious Diseases and Geographic Medicine, Department of Microbiology and Immunology, and Stanford Institute for the Environment, Stanford University, Stanford, CA 94305, USA. kmeibom@necker.fr
Science (New York, N.Y.)
|December 17, 2005
Summary
Vibrio cholerae acquires new genes through natural transformation on chitin, a process vital for its evolution as a pathogen. This genetic exchange relies on specific cellular machinery and regulatory pathways triggered by environmental cues.
Area of Science:
- Microbiology
- Genetics
- Evolutionary Biology
Background:
- The mosaic genome structure of Vibrio cholerae suggests significant horizontal gene transfer (HGT) has shaped its evolution.
- Vibrio cholerae is an autochthonous microbe in aquatic environments, often found associated with chitinous materials.
Purpose of the Study:
- To investigate the mechanisms by which Vibrio cholerae acquires new genetic material.
- To understand the role of natural transformation in the evolution of Vibrio cholerae.
Main Methods:
- Studied natural transformation of Vibrio cholerae during growth on chitin.
- Identified genetic and regulatory components required for transformation competence.
Main Results:
- Vibrio cholerae acquires genetic material via natural transformation when growing on chitin.
- Transformation competence requires a type IV pilus assembly complex and a DNA binding protein.
- Three regulatory cascades, activated by chitin, cell density, and nutrient limitation/stress, control transformation.
Conclusions:
- Chitin-rich environments facilitate horizontal gene transfer in Vibrio cholerae.
- Natural transformation is a key evolutionary mechanism for this human pathogen, driven by specific environmental triggers and genetic factors.
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