Abstract
We show that the disease tomato foot and root rot caused by the pathogenic fungus Fusarium oxysporum f. sp. radicis-lycopersici can be controlled by inoculation of seeds with cells of the efficient root colonizer Pseudomonas fluorescens WCS365, indicating that strain WCS365 is a biocontrol strain. The mechanism for disease suppression most likely is induced systemic resistance. P. fluorescens strain WCS365 and P. chlororaphis strain PCL1391, which acts through the production of the antibiotic phenazine-1-carboxamide, were differentially labeled using genes encoding autofluorescent proteins. Inoculation of seeds with a 1:1 mixture of these strains showed that, at the upper part of the root, the two cell types were present as microcolonies of either one or both cell types. Microcolonies at the lower root part were predominantly of one cell type. Mixed inoculation tended to improve biocontrol in comparison with single inoculations. In contrast to what was observed previously for strain PCL1391, mutations in various colonization genes, including sss, did not consistently decrease the biocontrol ability of strain WCS365. Multiple copies of the sss colonization gene in WCS365 improved neither colonization nor biocontrol by this strain. However, introduction of the sss-containing DNA fragment into the poor colonizer P. fluorescens WCS307 and into the good colonizer P. fluorescens F113 increased the competitive tomato root tip colonization ability of the latter strains 16- to 40-fold and 8- to 16-fold, respectively. These results show that improvement of the colonization ability of wild-type Pseudomonas strains by genetic engineering is a realistic goal.
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Claims 10
Claim · model-written summary
Seed inoculation with Pseudomonas fluorescens WCS365 controlled tomato foot and root rot caused by Fusarium oxysporum f. sp. radicis-lycopersici.
- Taxon
- tomato
Solanum lycopersicume0 - Treatment
- inoculation of seeds with cells of the efficient root colonizer Pseudomonas fluorescens WCS365e0
- Interactor
- Fusarium oxysporum f. sp. radicis-lycopersici
Fusarium oxysporum f. sp. radicis-lycopersicie0pathogen - Second interactor
- Pseudomonas fluorescens WCS365
.JPG?width=60)
Pseudomonas fluorescense0biocontrol_agent - Outcome
- tomato foot and root rote0
- Direction
- controllede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.JPG?width=500)
Verbatim
e0“the disease tomato foot and root rot caused by the pathogenic fungus Fusarium oxysporum f. sp. radicis-lycopersici can be controlled by inoculation of seeds with cells of the efficient root colonizer Pseudomonas fluorescens WCS365”
Claim · model-written summary
Induced systemic resistance was proposed as the likely mechanism of disease suppression.
- Taxon
- tomatoSolanum lycopersicume1
- Interactor
- Fusarium oxysporum f. sp. radicis-lycopersiciFusarium oxysporum f. sp. radicis-lycopersicie1pathogen
- Outcome
- disease suppressione0
- Qualifier
- induced systemic resistancee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The mechanism for disease suppression most likely is induced systemic resistance.”
e1“tomato foot and root rot caused by the pathogenic fungus Fusarium oxysporum f. sp. radicis-lycopersici”
Claim · model-written summary
At the upper root, mixed inoculation produced microcolonies containing one or both Pseudomonas cell types.
- Taxon
- TomatoSolanum lycopersicumt0
- Organ / stage
- upper part of the roote0
- Interactor
- P. fluorescens strain WCS365Pseudomonas fluorescense1biocontrol_agent
- Second interactor
- P. chlororaphis strain PCL1391Pseudomonas chlororaphise1biocontrol_agent
- Outcome
- microcolonies of either one or both cell typese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“at the upper part of the root, the two cell types were present as microcolonies of either one or both cell types”
e1“P. fluorescens strain WCS365 and P. chlororaphis strain PCL1391”
t0“Tomato-Fusarium oxysporum”
Claim · model-written summary
At the lower root, microcolonies predominantly contained one Pseudomonas cell type.
- Taxon
- TomatoSolanum lycopersicumt0
- Interactor
- P. fluorescens strain WCS365Pseudomonas fluorescense1biocontrol_agent
- Second interactor
- P. chlororaphis strain PCL1391Pseudomonas chlororaphise1biocontrol_agent
- Outcome
- Microcolonies at the lower root part were predominantly of one cell typee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Microcolonies at the lower root part were predominantly of one cell type.”
e1“P. fluorescens strain WCS365 and P. chlororaphis strain PCL1391”
t0“Tomato-Fusarium oxysporum”
Claim · model-written summary
Mixed inoculation tended to improve biocontrol relative to single inoculations.
- Taxon
- TomatoSolanum lycopersicumt0
- Treatment
- Mixed inoculatione0
- Interactor
- Fusarium oxysporum
_(Fusarium_oxysporum_f.sp._batatas)_1234227-PPT-Clemson_University.jpg?width=60)
Fusarium oxysporumt0pathogen - Outcome
- biocontrole0
- Direction
- improvee0
- Qualifier
- tended toe0
- Comparator
- single inoculationse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_(Fusarium_oxysporum_f.sp._batatas)_1234227-PPT-Clemson_University.jpg?width=500)
Verbatim
e0“Mixed inoculation tended to improve biocontrol in comparison with single inoculations.”
t0“Tomato-Fusarium oxysporum”
Claim · model-written summary
Mutations in WCS365 colonization genes including sss did not consistently reduce biocontrol.
- Taxon
- TomatoSolanum lycopersicumt0
- Treatment
- mutations in various colonization genes, including ssse0
- Interactor
- Fusarium oxysporumFusarium oxysporumt0pathogen
- Gene
- ssse0
- Outcome
- biocontrol ability of strain WCS365e0
- Direction
- did not consistently decreasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“mutations in various colonization genes, including sss, did not consistently decrease the biocontrol ability of strain WCS365”
t0“Tomato-Fusarium oxysporum”
Claim · model-written summary
Multiple sss copies in WCS365 did not improve its colonization.
- Taxon
- TomatoSolanum lycopersicumt0
- Treatment
- Multiple copies of the sss colonization gene in WCS365e0
- Interactor
- WCS365e0biocontrol_agent
- Gene
- ssse0
- Outcome
- colonizatione0
- Direction
- improved neithere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Multiple copies of the sss colonization gene in WCS365 improved neither colonization nor biocontrol by this strain.”
t0“Tomato-Fusarium oxysporum”
Claim · model-written summary
Multiple sss copies in WCS365 did not improve its biocontrol.
- Taxon
- TomatoSolanum lycopersicumt0
- Treatment
- Multiple copies of the sss colonization gene in WCS365e0
- Interactor
- Fusarium oxysporumFusarium oxysporumt0pathogen
- Gene
- ssse0
- Outcome
- biocontrole0
- Direction
- improved neithere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Multiple copies of the sss colonization gene in WCS365 improved neither colonization nor biocontrol by this strain.”
t0“Tomato-Fusarium oxysporum”
Claim · model-written summary
Introducing an sss DNA fragment increased competitive tomato root tip colonization by P. fluorescens WCS307 16- to 40-fold.
- Taxon
- tomatoSolanum lycopersicume0
- Treatment
- introduction of the sss-containing DNA fragment into the poor colonizer P. fluorescens WCS307e0
- Interactor
- P. fluorescens WCS307Pseudomonas fluorescense0biocontrol_agent
- Gene
- ssse0
- Outcome
- competitive tomato root tip colonization abilitye0
- Direction
- increasede0
- Value
- 16- to 40-folde0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“introduction of the sss-containing DNA fragment into the poor colonizer P. fluorescens WCS307 and into the good colonizer P. fluorescens F113 increased the competitive tomato root tip colonization ability of the latter strains 16- to 40-fold and 8- to 16-fold, respectively”
Claim · model-written summary
Introducing an sss DNA fragment increased competitive tomato root tip colonization by P. fluorescens F113 8- to 16-fold.
- Taxon
- tomatoSolanum lycopersicume0
- Treatment
- introduction of the sss-containing DNA fragment into the poor colonizer P. fluorescens WCS307 and into the good colonizer P. fluorescens F113e0
- Interactor
- P. fluorescens F113Pseudomonas fluorescense0biocontrol_agent
- Gene
- ssse0
- Outcome
- competitive tomato root tip colonization abilitye0
- Direction
- increasede0
- Value
- 8- to 16-folde0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“introduction of the sss-containing DNA fragment into the poor colonizer P. fluorescens WCS307 and into the good colonizer P. fluorescens F113 increased the competitive tomato root tip colonization ability of the latter strains 16- to 40-fold and 8- to 16-fold, respectively”
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