Journal article
Protozoan-Induced Regulation of Cyclic Lipopeptide Biosynthesis Is an Effective Predation Defense Mechanism for Pseudomonas fluorescens
Applied and environmental microbiology, Vol.75(21), pp.6804-6811
11/2009
Handle:
https://hdl.handle.net/2376/106807
PMCID: PMC2772446
PMID: 19717630
Abstract
Environmental bacteria are exposed to a myriad of biotic interactions that influence their function and survival. The grazing activity of protozoan predators significantly impacts the dynamics, diversification, and evolution of bacterial communities in soil ecosystems. To evade protozoan predation, bacteria employ various defense strategies. Soil-dwelling
Pseudomonas fluorescens
strains SS101 and SBW25 produce the cyclic lipopeptide surfactants (CLPs) massetolide and viscosin, respectively, in a quorum-sensing-independent manner. In this study, CLP production was shown to protect these bacteria from protozoan predation as, compared to CLP-deficient mutants, strains SS101 and SBW25 exhibited resistance to grazing by
Naegleria americana
in vitro and superior persistence in soil in the presence of this bacterial predator. In the wheat rhizosphere, CLP-producing strains had a direct deleterious impact on the survival of
N. americana
. In vitro assays further showed that
N. americana
was three times more sensitive to viscosin than to massetolide and that exposure of strain SS101 or SBW25 to this protozoan resulted in upregulation of CLP biosynthesis genes. Enhanced expression of the
massABC
and
viscABC
genes did not require physical contact between the two organisms as gene expression levels were up to threefold higher in bacterial cells harvested 1 cm from feeding protozoans than in cells collected 4 cm from feeding protozoans. These findings document a new natural function of CLPs and highlight that bacterium-protozoan interactions can result in activation of an antipredator response in prey populations.
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Details
- Title
- Protozoan-Induced Regulation of Cyclic Lipopeptide Biosynthesis Is an Effective Predation Defense Mechanism for Pseudomonas fluorescens
- Creators
- Mark Mazzola - USDA-ARS, 1104 N. Western Ave., Wenatchee, Washington 98801Irene de Bruijn - USDA-ARS, 1104 N. Western Ave., Wenatchee, Washington 98801Michael F Cohen - USDA-ARS, 1104 N. Western Ave., Wenatchee, Washington 98801Jos M Raaijmakers - USDA-ARS, 1104 N. Western Ave., Wenatchee, Washington 98801
- Publication Details
- Applied and environmental microbiology, Vol.75(21), pp.6804-6811
- Academic Unit
- Plant Pathology, Department of
- Publisher
- American Society for Microbiology (ASM)
- Identifiers
- 99900546877801842
- Language
- English
- Resource Type
- Journal article