Abstract
Enterobacter cloacae A-11 is a transposon mutant of strain 501R3 that was deficient in cucumber spermosphere colonization and in the utilization of certain carbohydrates (D. P. Roberts, C. J. Sheets, and J. S. Hartung, Can. J. Microbiol. 38:1128-1134, 1992). In vitro growth of strain A-11 was reduced or deficient on most carbohydrates that supported growth of strain 501R3 but was unaffected on fructose, glycerol, and all amino acids and organic acids tested. Colonization by strain A-11 was significantly reduced (P </= 0.05) for cucumber and radish seeds compared to that of strain 501R3, but colonization of pea, soybean, sunflower, and sweet corn seeds was not reduced. Pea seeds released several orders of magnitude more total carbohydrates and amino acids than cucumber and radish seeds and approximately 4,000-fold more fructose. Fructose was the only carbohydrate detected in the seed exudates which supported wild-type levels of in vitro growth of strain A-11. Soybean, sunflower, and sweet corn seeds also released significantly greater amounts of fructose and total carbohydrates and amino acids than cucumber or radish seeds. The exogenous addition of fructose to cucumber and radish seeds at quantities similar to the total quantity of carbohydrates released from pea seeds over 96 h increased the populations of strain A-11 to levels comparable to those of strain 501R3 in sterile sand. Molecular characterization of strain A-11 indicated that the mini-Tn5 kanamycin transposon was inserted in a region of the genome with significant homology to pfkA, which encodes phosphofructo kinase. A comparison of strain A-11 with Escherichia coli DF456, a known pfkA mutant, indicated that the nutritional loss phenotypes were identical. Furthermore, the pfkA homolog cloned from E. cloacae 501R3 complemented the nutritional loss phenotypes of both E. coli DF456 and E. cloacae A-11 and restored colonization by strain A-11 to near wild-type levels. These genetic and biochemical restoration experiments provide strong evidence that the quantities of reduced carbon sources found in seed exudates and the ability of microbes to use these compounds play important roles in the colonization of the spermosphere.
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Claims 9
Claim · model-written summary
Strain A-11 colonization was significantly reduced on cucumber and radish seeds compared with strain 501R3.
- Taxon
- cucumber and radish
Cucumis sativus
Raphanus sativuse1 - Treatment
- strain A-11e1
- Interactor
- Enterobacter cloacae
Enterobacter cloacaet0other - Outcome
- Colonizatione1
- Direction
- reducede1
- Comparator
- strain 501R3e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Role of pfkA and General Carbohydrate Catabolism in Seed Colonization by Enterobacter cloacae”
e1“Colonization by strain A-11 was significantly reduced (P </= 0.05) for cucumber and radish seeds compared to that of strain 501R3”
Claim · model-written summary
Strain A-11 colonization was not reduced on pea, soybean, sunflower and sweet corn seeds.
- Taxon
- pea, soybean, sunflower, and sweet corne2
- Treatment
- strain A-11e1
- Interactor
- Enterobacter cloacaeEnterobacter cloacaet0other
- Outcome
- colonizatione2
- Direction
- was not reducede2
- Comparator
- strain 501R3e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Role of pfkA and General Carbohydrate Catabolism in Seed Colonization by Enterobacter cloacae”
e1“Colonization by strain A-11 was significantly reduced (P </= 0.05) for cucumber and radish seeds compared to that of strain 501R3”
e2“but colonization of pea, soybean, sunflower, and sweet corn seeds was not reduced”
Claim · model-written summary
Pea seeds released several orders of magnitude more total carbohydrates and amino acids than cucumber and radish seeds.
- Taxon
- Pea seeds
Lathyrus oleraceuse3 - Outcome
- total carbohydrates and amino acidse3
- Value
- several orders of magnitudee3
- Comparator
- cucumber and radish seedse3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e3“Pea seeds released several orders of magnitude more total carbohydrates and amino acids than cucumber and radish seeds and approximately 4,000-fold more fructose”
Claim · model-written summary
Pea seeds released approximately 4,000-fold more fructose than cucumber and radish seeds.
- Taxon
- Pea seedsLathyrus oleraceuse3
- Outcome
- fructosee3
- Value
- approximately 4,000-folde3
- Comparator
- cucumber and radish seedse3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e3“Pea seeds released several orders of magnitude more total carbohydrates and amino acids than cucumber and radish seeds and approximately 4,000-fold more fructose”
Claim · model-written summary
Fructose was the only seed-exudate carbohydrate that supported wild-type levels of in vitro growth of strain A-11.
Not reportedTaxon
Verbatim
e5“Fructose was the only carbohydrate detected in the seed exudates which supported wild-type levels of in vitro growth of strain A-11”
Claim · model-written summary
Adding fructose to cucumber and radish seeds increased strain A-11 populations to levels comparable to strain 501R3.
- Taxon
- cucumber and radish seedsCucumis sativusRaphanus sativuse6
- Treatment
- exogenous addition of fructosee6
- Interactor
- Enterobacter cloacaeEnterobacter cloacaet0other
- Outcome
- populations of strain A-11e6
- Direction
- increasede6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Role of pfkA and General Carbohydrate Catabolism in Seed Colonization by Enterobacter cloacae”
e6“The exogenous addition of fructose to cucumber and radish seeds at quantities similar to the total quantity of carbohydrates released from pea seeds over 96 h increased the populations of strain A-11 to levels comparable to those of strain 501R3 in sterile sand”
Claim · model-written summary
The mini-Tn5 kanamycin transposon of strain A-11 lies in a region homologous to pfkA.
Not reportedTaxon
Verbatim
e7“Molecular characterization of strain A-11 indicated that the mini-Tn5 kanamycin transposon was inserted in a region of the genome with significant homology to pfkA, which encodes phosphofructo kinase”
Claim · model-written summary
Strain A-11 and Escherichia coli DF456 have identical nutritional loss phenotypes.
Not reportedTaxon
Verbatim
e0“A comparison of strain A-11 with Escherichia coli DF456, a known pfkA mutant, indicated that the nutritional loss phenotypes were identical”
Claim · model-written summary
The pfkA homolog from E. cloacae 501R3 complemented the nutritional loss phenotypes and restored strain A-11 colonization to near wild-type levels.
- Treatment
- pfkA homolog cloned from E. cloacae 501R3e0
- Interactor
- Enterobacter cloacaeEnterobacter cloacaet0other
- Gene
- pfkA homologe0
- Outcome
- colonization by strain A-11e0
- Direction
- restorede0
Not reportedTaxonComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Role of pfkA and General Carbohydrate Catabolism in Seed Colonization by Enterobacter cloacae”
e0“the pfkA homolog cloned from E. cloacae 501R3 complemented the nutritional loss phenotypes of both E. coli DF456 and E. cloacae A-11 and restored colonization by strain A-11 to near wild-type levels”