Cyclic Lipopeptide Surfactant Production by <i>Pseudomonas fluorescens</i> SS101 Is Not Required for Suppression of Complex <i>Pythium</i> spp. Populations

Mazzola, Mark; Zhao, Xue; Cohen, Michael F.; Raaijmakers, Jos M.

doi:10.1094/phyto-97-10-1348

Cited by 36 publications

(19 citation statements)

References 40 publications

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“…These results suggest that the production of CLPs is targeted primarily toward predators and is less important in competition with other (micro)organisms in soil and rhizosphere environments. This observation is consistent with previous work (35) which showed that strain SS101 and the CLP-deficient mutant 10.24 exhibited similar levels of activity against indigenous root-infecting Pythium species, indicating that massetolide did not play a major role in toxicity against this group of coexisting soil inhabitants.…”

Section: Discussionsupporting

confidence: 92%

Protozoan-Induced Regulation of Cyclic Lipopeptide Biosynthesis Is an Effective Predation Defense Mechanism forPseudomonas fluorescens

Mazzola¹,

Bruijn

Cohen

et al. 2009

Appl Environ Microbiol

113

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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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Section: Discussionsupporting

confidence: 92%

Protozoan-Induced Regulation of Cyclic Lipopeptide Biosynthesis Is an Effective Predation Defense Mechanism forPseudomonas fluorescens

Mazzola¹,

Bruijn

Cohen

et al. 2009

Appl Environ Microbiol

113

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“…For instance, massetolide A plays a role in protecting tomato plant roots against Phytophthora infestans (61) but is not required for suppression of complex Pythium sp. populations resident in orchard soils (44). We cannot exclude the possibilities that P. entomophila possesses extended biocontrol activity and that entolysin could play a role under conditions other than those of Pythium infection of cucumber plant roots.…”

Section: Discussionmentioning

confidence: 96%

Association of Hemolytic Activity ofPseudomonas entomophila, a Versatile Soil Bacterium, with Cyclic Lipopeptide Production

Vallet-Gély

Новиков

Augusto

et al. 2010

Appl Environ Microbiol

126

130

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Pseudomonas entomophila is an entomopathogenic bacterium that is able to infect and kill Drosophila melanogaster upon ingestion. Its genome sequence suggests that it is a versatile soil bacterium closely related to Pseudomonas putida. The GacS/GacA two-component system plays a key role in P. entomophila pathogenicity, controlling many putative virulence factors and AprA, a secreted protease important to escape the fly immune response. P. entomophila secretes a strong diffusible hemolytic activity. Here, we showed that this activity is linked to the production of a new cyclic lipopeptide containing 14 amino acids and a 3-C 10 OH fatty acid that we called entolysin. Three nonribosomal peptide synthetases (EtlA, EtlB, EtlC) were identified as responsible for entolysin biosynthesis. Two additional components (EtlR, MacAB) are necessary for its production and secretion. The P. entomophila GacS/GacA two-component system regulates entolysin production, and we demonstrated that its functioning requires two small RNAs and two RsmA-like proteins. Finally, entolysin is required for swarming motility, as described for other lipopeptides, but it does not participate in the virulence of P. entomophila for Drosophila. While investigating the physiological role of entolysin, we also uncovered new phenotypes associated with P. entomophila, including strong biocontrol abilities.

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“…2007). However, in biocontrol of Pythium root rot of wheat and apple seedlings, the massetolide‐deficient mutant of strain SS101 was equally effective (Mazzola et al. 2007).…”

Section: Introductionmentioning

confidence: 99%

Functional, genetic and chemical characterization of biosurfactants produced by plant growth-promotingPseudomonas putida267

Kruijt¹,

Tran

Raaijmakers³

2009

Journal of Applied Microbiology

107

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Aims: Plant growth‐promoting Pseudomonas putida strain 267, originally isolated from the rhizosphere of black pepper, produces biosurfactants that cause lysis of zoospores of the oomycete pathogen Phytophthora capsici. The biosurfactants were characterized, the biosynthesis gene(s) partially identified, and their role in control of Phytophthora damping‐off of cucumber evaluated. Methods and Results: The biosurfactants were shown to lyse zoospores of Phy. capsici and inhibit growth of the fungal pathogens Botrytis cinerea and Rhizoctonia solani. In vitro assays further showed that the biosurfactants of strain 267 are essential in swarming motility and biofilm formation. In spite of the zoosporicidal activity, the biosurfactants did not play a significant role in control of Phytophthora damping‐off of cucumber, since both wild type strain 267 and its biosurfactant‐deficient mutant were equally effective, and addition of the biosurfactants did not provide control. Genetic characterization revealed that surfactant biosynthesis in strain 267 is governed by homologues of PsoA and PsoB, two nonribosomal peptide synthetases involved in production of the cyclic lipopeptides (CLPs) putisolvin I and II. The structural relatedness of the biosurfactants of strain 267 to putisolvins I and II was supported by LC‐MS and MS‐MS analyses. Conclusions: The biosurfactants produced by Ps. putida 267 were identified as putisolvin‐like CLPs; they are essential in swarming motility and biofilm formation, and have zoosporicidal and antifungal activities. Strain 267 provides excellent biocontrol activity against Phytophthora damping‐off of cucumber, but the lipopeptide surfactants are not involved in disease suppression. Significance and Impact of the Study: Pseudomonas putida 267 suppresses Phy. capsici damping‐off of cucumber and provides a potential supplementary strategy to control this economically important oomycete pathogen. The putisolvin‐like biosurfactants exhibit zoosporicidal and antifungal activities, yet they do not contribute to biocontrol of Phy. capsici and colonization of cucumber roots by Ps. putida 267. These results suggest that Ps. putida 267 employs other, yet uncharacterized, mechanisms to suppress Phy. capsici.

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Cyclic Lipopeptide Surfactant Production by Pseudomonas fluorescens SS101 Is Not Required for Suppression of Complex Pythium spp. Populations

Cited by 36 publications

References 40 publications

Protozoan-Induced Regulation of Cyclic Lipopeptide Biosynthesis Is an Effective Predation Defense Mechanism forPseudomonas fluorescens

Protozoan-Induced Regulation of Cyclic Lipopeptide Biosynthesis Is an Effective Predation Defense Mechanism forPseudomonas fluorescens

Association of Hemolytic Activity ofPseudomonas entomophila, a Versatile Soil Bacterium, with Cyclic Lipopeptide Production

Functional, genetic and chemical characterization of biosurfactants produced by plant growth-promotingPseudomonas putida267

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