Abstract
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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Claims 11
Claim · model-written summary
Strain 267 biosurfactants lysed Phy. capsici zoospores.
- Taxon
- cucumber
Cucumis sativust0 - Interactor
- Phy. capsicie0pathogen
- Outcome
- lyse zoospores of Phy. capsicie0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The biosurfactants were shown to lyse zoospores of Phy. capsici”
t0“Phytophthora damping-off of cucumber evaluated”
Claim · model-written summary
The biosurfactants inhibited Botrytis cinerea growth.
- Taxon
- cucumberCucumis sativust0
- Interactor
- Botrytis cinerea
Botrytis cinereae0pathogen - Outcome
- growth of the fungal pathogens Botrytis cinereae0
- Direction
- inhibite0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“inhibit growth of the fungal pathogens Botrytis cinerea and Rhizoctonia solani”
t0“Phytophthora damping-off of cucumber evaluated”
Claim · model-written summary
The biosurfactants inhibited Rhizoctonia solani growth.
- Taxon
- cucumberCucumis sativust0
- Interactor
- Rhizoctonia solani
Rhizoctonia solanie0pathogen - Outcome
- Rhizoctonia solanie0
- Direction
- inhibite0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“inhibit growth of the fungal pathogens Botrytis cinerea and Rhizoctonia solani”
t0“Phytophthora damping-off of cucumber evaluated”
Claim · model-written summary
Strain 267 biosurfactants were essential for swarming motility.
- Taxon
- cucumberCucumis sativust0
- Outcome
- swarming motilitye0
- Qualifier
- strain 267e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the biosurfactants of strain 267 are essential in swarming motility and biofilm formation”
t0“Phytophthora damping-off of cucumber evaluated”
Claim · model-written summary
Strain 267 biosurfactants were essential for biofilm formation.
- Taxon
- cucumberCucumis sativust0
- Outcome
- biofilm formatione0
- Qualifier
- strain 267e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the biosurfactants of strain 267 are essential in swarming motility and biofilm formation”
t0“Phytophthora damping-off of cucumber evaluated”
Claim · model-written summary
Wild type and biosurfactant-deficient strain 267 were equally effective against cucumber damping-off.
- Taxon
- cucumberCucumis sativust0
- Treatment
- wild type strain 267e0
- Interactor
- strain 267e0biocontrol_agent
- Outcome
- equally effectivee0
- Direction
- equallye0
- Comparator
- biosurfactant-deficient mutante0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“both wild type strain 267 and its biosurfactant-deficient mutant were equally effective”
t0“Phytophthora damping-off of cucumber evaluated”
Claim · model-written summary
Adding biosurfactants did not control cucumber damping-off.
- Taxon
- cucumberCucumis sativust0
- Treatment
- addition of the biosurfactantse0
- Outcome
- controle0
- Direction
- did not providee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“addition of the biosurfactants did not provide control”
t0“Phytophthora damping-off of cucumber evaluated”
Claim · model-written summary
Strain 267 surfactant biosynthesis was governed by PsoA and PsoB homologues.
- Taxon
- cucumberCucumis sativust0
- Gene
- PsoA and PsoBe0
- Outcome
- surfactant biosynthesis in strain 267e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“surfactant biosynthesis in strain 267 is governed by homologues of PsoA and PsoB”
t0“Phytophthora damping-off of cucumber evaluated”
Claim · model-written summary
Strain 267 biosurfactants were identified as putisolvin-like CLPs.
- Taxon
- cucumberCucumis sativust0
- Interactor
- Ps. putida 267e0biocontrol_agent
- Outcome
- putisolvin-like CLPse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The biosurfactants produced by Ps. putida 267 were identified as putisolvin-like CLPs”
t0“Phytophthora damping-off of cucumber evaluated”
Claim · model-written summary
Pseudomonas putida 267 suppressed Phy. capsici damping-off of cucumber.
- Taxon
- cucumberCucumis sativuse0
- Treatment
- Pseudomonas putida 267e0
- Interactor
- Phy. capsicie0pathogen
- Second interactor
- Pseudomonas putida 267
Pseudomonas putidae0biocontrol_agent - Outcome
- Phy. capsici damping-offe0
- Direction
- suppressese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Pseudomonas putida 267 suppresses Phy. capsici damping-off of cucumber”
Claim · model-written summary
Biosurfactants did not contribute to cucumber root colonization by Ps. putida 267.
- Taxon
- cucumberCucumis sativuse0
- Interactor
- Ps. putida 267e0biocontrol_agent
- Outcome
- colonization of cucumber roots by Ps. putida 267e0
- Direction
- do not contributee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“they do not contribute to biocontrol of Phy. capsici and colonization of cucumber roots by Ps. putida 267”
The same questions in other papers
Pseudomonas putida · disease · Cucumis sativus (cucumber)Results agree
1 paper in the same direction as this paper
- positive
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.