Abstract
Strains of Enterobacter cloacae show promise as biocontrol agents for Pythium ultimum-induced damping-off on cucumber and other crops. E. cloacae A145 is a mini-Tn5 Km transposon mutant of strain 501R3 that was significantly reduced in suppression of damping-off on cucumber caused by P. ultimum. Strain A145 was deficient in colonization of cucumber, sunflower, and wheat seeds and significantly reduced in colonization of corn and cowpea seeds relative to strain 501R3. Populations of strain A145 were also significantly lower than those of strain 501R3 at all sampling times in cucumber, wheat, and sunflower rhizosphere. Populations of strain A145 were not detectable in any rhizosphere after 42 days, while populations of strain 501R3 remained at substantial levels throughout all experiments. Molecular characterization of strain A145 indicated mini-Tn5 Km was inserted in a region of the E. cloacae genome with a high degree of DNA and amino acid sequence similarity to rpiA, which encodes ribose-5-phosphate isomerase. In Escherichia coli, RpiA catalyzes the interconversion of ribose-5-phosphate and ribulose-5-phosphate and is a key enzyme in the pentose phosphate pathway. Ribose-5-phosphate isomerase activity in cell lysates from strain A145 was approximately 3.5% of that from strain 501R3. In addition, strain A145 was a ribose auxotroph, as expected for an rpiA mutant. Introduction of a 1.0-kb DNA fragment containing only the rpiA homologue into strain A145 restored ribose phosphate isomerase activity, prototrophy, seedling colonization, and disease suppression to levels similar to those associated with strain 501R3. Experiments reported here indicate a key role for rpiA and possibly the pentose phosphate pathway in suppression of damping-off and colonization of subterranean portions of plants by E. cloacae.
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Claims 11
Claim · model-written summary
The mini-Tn5 Km mutant A145 of E. cloacae was significantly reduced in suppressing cucumber damping-off caused by P. ultimum relative to parent strain 501R3.
- Taxon
- cucumber
Cucumis sativuse1 - Material
- A145e1
- Treatment
- mini-Tn5 Km transposon mutante1
- Interactor
- P. ultimumGlobisporangium ultimume1pathogen
- Second interactor
- E. cloacae
Enterobacter cloacaee1biocontrol_agent - Outcome
- suppression of damping-offe1
- Direction
- significantly reducede1
- Comparator
- strain 501R3e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Strains of Enterobacter cloacae show promise as biocontrol agents for Pythium ultimum-induced damping-off on cucumber and other crops.”
e1“E. cloacae A145 is a mini-Tn5 Km transposon mutant of strain 501R3 that was significantly reduced in suppression of damping-off on cucumber caused by P. ultimum”
Claim · model-written summary
Strain A145 was deficient in seed colonization of cucumber, sunflower and wheat relative to strain 501R3.
- Taxon
- cucumber, sunflower, and wheatCucumis sativus
Helianthus annuus
Triticum aestivume2 - Organ / stage
- seedse2
- Treatment
- Strain A145e2
- Interactor
- Enterobacter cloacaeEnterobacter cloacaee0biocontrol_agent
- Outcome
- colonizatione2
- Direction
- deficiente2
- Comparator
- strain 501R3e2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Strains of Enterobacter cloacae show promise as biocontrol agents for Pythium ultimum-induced damping-off on cucumber and other crops.”
e2“Strain A145 was deficient in colonization of cucumber, sunflower, and wheat seeds and significantly reduced in colonization of corn and cowpea seeds relative to strain 501R3”
Claim · model-written summary
Strain A145 was significantly reduced in seed colonization of corn and cowpea relative to strain 501R3.
- Taxon
- corn and cowpea
Vigna unguiculata
Zea mays subsp. mayse2 - Organ / stage
- seedse2
- Treatment
- Strain A145e2
- Interactor
- Enterobacter cloacaeEnterobacter cloacaee0biocontrol_agent
- Outcome
- colonizatione2
- Direction
- significantly reducede2
- Comparator
- strain 501R3e2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Strains of Enterobacter cloacae show promise as biocontrol agents for Pythium ultimum-induced damping-off on cucumber and other crops.”
e2“Strain A145 was deficient in colonization of cucumber, sunflower, and wheat seeds and significantly reduced in colonization of corn and cowpea seeds relative to strain 501R3”
Claim · model-written summary
Populations of strain A145 were significantly lower than those of strain 501R3 at all sampling times in cucumber, wheat and sunflower rhizosphere.
- Taxon
- cucumber, wheat, and sunflowerCucumis sativusHelianthus annuusTriticum aestivume3
- Organ / stage
- rhizospheree3
- Treatment
- strain A145e3
- Interactor
- Enterobacter cloacaeEnterobacter cloacaee0biocontrol_agent
- Outcome
- Populations of strain A145e3
- Direction
- significantly lowere3
- Comparator
- strain 501R3e3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Strains of Enterobacter cloacae show promise as biocontrol agents for Pythium ultimum-induced damping-off on cucumber and other crops.”
e3“Populations of strain A145 were also significantly lower than those of strain 501R3 at all sampling times in cucumber, wheat, and sunflower rhizosphere. Populations of strain A145 were not detectable in any rhizosphere after 42 days”
Claim · model-written summary
Populations of strain A145 were not detectable in any rhizosphere after 42 days.
- Taxon
- cucumberCucumis sativuse0
- Organ / stage
- rhizospheree3
- Interactor
- Enterobacter cloacaeEnterobacter cloacaee0biocontrol_agent
- Outcome
- Populations of strain A145e3
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Strains of Enterobacter cloacae show promise as biocontrol agents for Pythium ultimum-induced damping-off on cucumber and other crops.”
e3“Populations of strain A145 were also significantly lower than those of strain 501R3 at all sampling times in cucumber, wheat, and sunflower rhizosphere. Populations of strain A145 were not detectable in any rhizosphere after 42 days”
Claim · model-written summary
Mini-Tn5 Km inserted into a region of the E. cloacae genome with high DNA and amino acid similarity to rpiA.
- Taxon
- cucumberCucumis sativuse0
- Interactor
- E. cloacaeEnterobacter cloacaee4biocontrol_agent
- Gene
- rpiAe4
- Outcome
- DNA and amino acid sequence similarity to rpiAe4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Strains of Enterobacter cloacae show promise as biocontrol agents for Pythium ultimum-induced damping-off on cucumber and other crops.”
e4“Molecular characterization of strain A145 indicated mini-Tn5 Km was inserted in a region of the E. cloacae genome with a high degree of DNA and amino acid sequence similarity to rpiA”
Claim · model-written summary
Ribose-5-phosphate isomerase activity in cell lysates of strain A145 was about 3.5% of that of strain 501R3.
- Taxon
- cucumberCucumis sativuse0
- Treatment
- strain A145e5
- Outcome
- Ribose-5-phosphate isomerase activity in cell lysatese5
- Direction
- lowerinferrede5
- Value
- 3.5%e5
- Comparator
- strain 501R3e5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Strains of Enterobacter cloacae show promise as biocontrol agents for Pythium ultimum-induced damping-off on cucumber and other crops.”
e5“Ribose-5-phosphate isomerase activity in cell lysates from strain A145 was approximately 3.5% of that from strain 501R3. In addition, strain A145 was a ribose auxotroph, as expected for an rpiA mutant”
Claim · model-written summary
Strain A145 was a ribose auxotroph, as expected for an rpiA mutant.
- Taxon
- cucumberCucumis sativuse0
- Gene
- rpiAe5
- Outcome
- ribose auxotrophe5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Strains of Enterobacter cloacae show promise as biocontrol agents for Pythium ultimum-induced damping-off on cucumber and other crops.”
e5“Ribose-5-phosphate isomerase activity in cell lysates from strain A145 was approximately 3.5% of that from strain 501R3. In addition, strain A145 was a ribose auxotroph, as expected for an rpiA mutant”
Claim · model-written summary
Introducing the rpiA homologue fragment into strain A145 restored its ribose phosphate isomerase activity, prototrophy and seedling colonization to levels similar to strain 501R3.
- Taxon
- cucumberCucumis sativuse0
- Treatment
- Introduction of a 1.0-kb DNA fragment containing only the rpiA homologuee6
- Gene
- rpiA homologuee6
- Outcome
- ribose phosphate isomerase activity, prototrophy, seedling colonizatione6
- Direction
- restorede6
- Qualifier
- to levels similar to those associated with strain 501R3e6
- Comparator
- strain 501R3e6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Strains of Enterobacter cloacae show promise as biocontrol agents for Pythium ultimum-induced damping-off on cucumber and other crops.”
e6“Introduction of a 1.0-kb DNA fragment containing only the rpiA homologue into strain A145 restored ribose phosphate isomerase activity, prototrophy, seedling colonization, and disease suppression to levels similar to those associated with strain 501R3”
Claim · model-written summary
Introducing the rpiA homologue fragment into strain A145 restored disease suppression to levels similar to strain 501R3.
- Taxon
- cucumberCucumis sativuse0
- Treatment
- Introduction of a 1.0-kb DNA fragment containing only the rpiA homologuee6
- Gene
- rpiA homologuee6
- Outcome
- disease suppressione6
- Direction
- restorede6
- Comparator
- strain 501R3e6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Strains of Enterobacter cloacae show promise as biocontrol agents for Pythium ultimum-induced damping-off on cucumber and other crops.”
e6“Introduction of a 1.0-kb DNA fragment containing only the rpiA homologue into strain A145 restored ribose phosphate isomerase activity, prototrophy, seedling colonization, and disease suppression to levels similar to those associated with strain 501R3”
Claim · model-written summary
The rpiA gene has a key role in suppression of damping-off and in colonization of subterranean plant portions by E. cloacae, possibly through the pentose phosphate pathway.
- Taxon
- cucumberCucumis sativuse0
- Gene
- rpiAe7
- Outcome
- suppression of damping-offe7
- Qualifier
- possiblye7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Strains of Enterobacter cloacae show promise as biocontrol agents for Pythium ultimum-induced damping-off on cucumber and other crops.”
e7“Experiments reported here indicate a key role for rpiA and possibly the pentose phosphate pathway in suppression of damping-off and colonization of subterranean portions of plants by E. cloacae”