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Adherence of Bacteria to Plant Surfaces Measured in the Laboratory
Published on: June 19, 2018
Role for Rhizobium rhizogenes K84 cell envelope polysaccharides in surface interactions
Ana M Abarca-Grau1, Lindsey P Burbank, Héctor D de Paz
1Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias, Valencia, Spain.
Applied and Environmental Microbiology
|January 3, 2012
Summary
Rhizobium rhizogenes K84 biofilm formation relies on specific polysaccharides. Mutations affecting capsular polysaccharide (CPS) and lipopolysaccharide (LPS) impact bacterial attachment and colonization on surfaces.
Area of Science:
- Microbiology
- Plant Pathology
- Biochemistry
Background:
- Rhizobium rhizogenes strain K84 is a key biocontrol agent for crown gall disease.
- This bacterium forms robust biofilms on both abiotic and plant root surfaces.
- Surface interactions are crucial for its efficacy as a biocontrol agent.
Purpose of the Study:
- To investigate the genetic basis of Rhizobium rhizogenes K84's surface interactions and biofilm formation.
- To identify genes and cellular components responsible for bacterial adhesion and colonization.
- To understand the roles of capsular polysaccharides and lipopolysaccharides in these processes.
Main Methods:
- Genetic screening to identify mutants with altered surface interactions.
- Biofilm formation assays on abiotic surfaces (polypropylene) and biological surfaces (root tips).
- Gene expression analysis and characterization of polysaccharide mutants (wcbD and rkpK).
Main Results:
- A wcbD mutant showed impaired biofilm formation on abiotic surfaces but normal formation on root tips, indicating a role in abiotic surface attachment.
- A rkpK mutant exhibited denser biofilms on both surfaces and was deficient in O-antigen synthesis, producing rough lipopolysaccharide (LPS).
- Strain K84 produces a type II capsular polysaccharide (CPS) involved in cell-surface interactions, and its O antigen is essential for cell-cell interactions within biofilms.
Conclusions:
- Specific polysaccharides, including a type II CPS and O-antigen LPS, are critical for Rhizobium rhizogenes K84's biofilm formation and surface colonization.
- Understanding these surface components can inform strategies to enhance biocontrol efficacy.
- The distinct roles of CPS and LPS in mediating different aspects of bacterial-surface interactions were elucidated.
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