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Sulfonate desulfurization in Rhodococcus from wheat rhizosphere communities
Achim Schmalenberger1, Sarah Hodge, Malcolm J Hawkesford
1Faculty of Life Sciences, University of Manchester, Manchester, UK.
FEMS Microbiology Ecology
|January 6, 2009
Summary
Soil bacteria Rhodococcus can break down organic sulfonates, a key sulfur form. These bacteria, identified by asfAB genes, are present in wheat roots but their community structure isn't significantly altered by sulfate fertilization.
Area of Science:
- Soil microbiology
- Biogeochemical cycling
- Plant-microbe interactions
Background:
- Organically bound sulfur, predominantly sulfonates, constitutes ~90% of soil sulfur.
- Understanding the microbial breakdown of sulfonates is crucial for soil sulfur dynamics.
Purpose of the Study:
- To investigate the role of Actinobacteria, specifically Rhodococcus, in arylsulfonate desulfonation in wheat rhizospheres.
- To determine if sulfur fertilization regimes influence the desulfonating bacterial community.
Main Methods:
- Isolation and characterization of desulfonating Rhodococcus strains from wheat rhizospheres.
- Analysis of asfAB gene presence and expression in Rhodococcus isolates.
- Community structure analysis using 16S rRNA gene DGGE and asfAB gene libraries.
- Molecular analysis (RFLP/T-RFLP) of rhizosphere communities under different fertilization treatments.
Main Results:
- Rhodococcus strains with desulfonating activity and asfAB genes were isolated from wheat rhizospheres.
- asfAB gene expression was significantly upregulated when Rhodococcus grew with sulfonates compared to sulfate.
- While overall actinobacterial community structure was influenced by fertilization, the desulfonating Rhodococcus community showed minimal response to sulfate supply.
Conclusions:
- Specific Rhodococcus strains possess the capability to desulfonate arylsulfonates in the wheat rhizosphere.
- The presence and activity of these desulfonating bacteria are linked to the asfAB genes.
- The desulfonating Rhodococcus community composition appears largely independent of short-term sulfate fertilization strategies in this long-term experiment.
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