Paper · 1990 · FEMS Microbiology Letters

Interactions between bacteria-feeding nematodes and bacteria in the rape rhizosphere: effects on root exudation and distribution of bacteria

Peter Sundin; Anders Valeur; Stefan Olsson; et al.

9
claims
19
verbatim quotes
47
citations
2
research areas
—
Not open access

Abstract

Effects of rhizosphere bacteria (RB), and rhizosphere bacteria with bacteria-feeding nematodes (RBN), on the composition of root exudate were examined after 2 weeks in gnotobiotic culture systems with rape seedlings (Brassica napus (L.)). The amounts of low molecular weight carbohydrates and of some free amino acids, per unit root dry weight, in the exudates were lower in the RB and RBN treatments than in the axenic control (R treatment). The growth of nematodes implied a production of bacterial cells in the RBN treatment 2.6 times that in the RB treatment. The bacterial growth in the RB treatment and the bacterial growth in combination with grazing by nematodes in the RBN treatment implied 24 and 63 times as much exudation of organic carbon, respectively, as in the R treatment. Most bacteria were attached to sand particles. The nematodes being suspension-feeders, decreased the proportion of free bacteria from 6% in the RB treatment to 2% in the RBN treatment. The numbers of attached bacteria in the RBN treratment were positively correlated with the numbers of nematodes, indicating stimulation of bacterial growth by the grazing.

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Claims 9

Intervention effectobservedoriginal resultnegativemeasured

Claim · model-written summary

Root exudate low molecular weight carbohydrates were lower with bacteria alone and with bacteria plus nematodes than in axenic controls.

Organ / stage
roote0
Treatment
RB and RBN treatmentse0
Outcome
low molecular weight carbohydratese0
Direction
lowere0
Comparator
axenic control (R treatment)e0

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Brassica napus
Brassica napus · TaxonDidier Descouens · CC BY-SA 4.0 · Wikimedia Commons ↗

Verbatim

e0

“The amounts of low molecular weight carbohydrates and of some free amino acids, per unit root dry weight, in the exudates were lower in the RB and RBN treatments than in the axenic control (R treatment).”

✓ located verbatim in the source · abstract, characters 239–442 · show in text ↑
t0

“rape”

✓ located verbatim in the source · title, characters 68–72 · show in text ↑
Intervention effectobservedoriginal resultnegativemeasured

Claim · model-written summary

Some free amino acids in root exudates were lower with bacteria alone and with bacteria plus nematodes than in axenic controls.

Organ / stage
roote0
Treatment
RB and RBN treatmentse0
Outcome
free amino acidse0
Direction
lowere0
Comparator
axenic control (R treatment)e0

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Brassica napus
Brassica napus · TaxonDidier Descouens · CC BY-SA 4.0 · Wikimedia Commons ↗

Verbatim

e0

“The amounts of low molecular weight carbohydrates and of some free amino acids, per unit root dry weight, in the exudates were lower in the RB and RBN treatments than in the axenic control (R treatment).”

✓ located verbatim in the source · abstract, characters 239–442 · show in text ↑
t0

“rape”

✓ located verbatim in the source · title, characters 68–72 · show in text ↑
Intervention effectobservedoriginal resultmeasured

Claim · model-written summary

Nematode growth implied 2.6 times as much bacterial cell production with bacteria plus nematodes as with bacteria alone.

Treatment
RBN treatmente0
Interactor
nematodesNematodae0other
Outcome
production of bacterial cellse0
Value
2.6 timese0
Comparator
RB treatmente0

Not reportedDirection

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Brassica napus
Brassica napus · TaxonDidier Descouens · CC BY-SA 4.0 · Wikimedia Commons ↗

Verbatim

e0

“The growth of nematodes implied a production of bacterial cells in the RBN treatment 2.6 times that in the RB treatment.”

✓ located verbatim in the source · abstract, characters 443–563 · show in text ↑
t0

“rape”

✓ located verbatim in the source · title, characters 68–72 · show in text ↑
Intervention effectobservedoriginal resultmeasured

Claim · model-written summary

Bacteria alone implied 24 times as much organic carbon exudation as axenic controls.

Treatment
RB treatmente0
Outcome
exudation of organic carbone0
Value
24e0
Comparator
R treatmente0

Not reportedDirection

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Brassica napus
Brassica napus · TaxonDidier Descouens · CC BY-SA 4.0 · Wikimedia Commons ↗

Verbatim

e0

“The bacterial growth in the RB treatment and the bacterial growth in combination with grazing by nematodes in the RBN treatment implied 24 and 63 times as much exudation of organic carbon, respectively, as in the R treatment.”

✓ located verbatim in the source · abstract, characters 564–789 · show in text ↑
t0

“rape”

✓ located verbatim in the source · title, characters 68–72 · show in text ↑
Intervention effectobservedoriginal resultmeasured

Claim · model-written summary

Bacteria with nematode grazing implied 63 times as much organic carbon exudation as axenic controls.

Treatment
RBN treatmente0
Interactor
nematodesNematodae0other
Outcome
exudation of organic carbone0
Value
63e0
Comparator
R treatmente0

Not reportedDirection

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Brassica napus
Brassica napus · TaxonDidier Descouens · CC BY-SA 4.0 · Wikimedia Commons ↗

Verbatim

e0

“The bacterial growth in the RB treatment and the bacterial growth in combination with grazing by nematodes in the RBN treatment implied 24 and 63 times as much exudation of organic carbon, respectively, as in the R treatment.”

✓ located verbatim in the source · abstract, characters 564–789 · show in text ↑
t0

“rape”

✓ located verbatim in the source · title, characters 68–72 · show in text ↑
Observationobservedoriginal resultmeasured

Claim · model-written summary

Most rhizosphere bacteria were attached to sand particles.

Outcome
bacteria were attached to sand particlese0

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Brassica napus
Brassica napus · TaxonDidier Descouens · CC BY-SA 4.0 · Wikimedia Commons ↗

Verbatim

e0

“Most bacteria were attached to sand particles.”

✓ located verbatim in the source · abstract, characters 790–836 · show in text ↑
t0

“rape”

✓ located verbatim in the source · title, characters 68–72 · show in text ↑
Intervention effectobservedoriginal resultmeasured

Claim · model-written summary

Nematodes decreased the proportion of free bacteria from 6% under bacteria alone to 2% under bacteria plus nematodes.

Treatment
RBN treatmente0
Interactor
nematodesNematodae0other
Outcome
proportion of free bacteriae0
Direction
decreasede0
Value
2%e0
Qualifier
6%e0
Comparator
RB treatmente0

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Brassica napus
Brassica napus · TaxonDidier Descouens · CC BY-SA 4.0 · Wikimedia Commons ↗

Verbatim

e0

“The nematodes being suspension-feeders, decreased the proportion of free bacteria from 6% in the RB treatment to 2% in the RBN treatment.”

✓ located verbatim in the source · abstract, characters 837–974 · show in text ↑
t0

“rape”

✓ located verbatim in the source · title, characters 68–72 · show in text ↑
Associationobservedoriginal resultmeasured

Claim · model-written summary

Numbers of attached bacteria under bacteria plus nematodes were positively correlated with nematode numbers.

Interactor
nematodesNematodae0other
Outcome
numbers of attached bacteriae0
Direction
positively correlatede0

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Brassica napus
Brassica napus · TaxonDidier Descouens · CC BY-SA 4.0 · Wikimedia Commons ↗

Verbatim

e0

“The numbers of attached bacteria in the RBN treratment were positively correlated with the numbers of nematodes, indicating stimulation of bacterial growth by the grazing.”

✓ located verbatim in the source · abstract, characters 975–1146 · show in text ↑
t0

“rape”

✓ located verbatim in the source · title, characters 68–72 · show in text ↑
Mechanismauthor interpretationoriginal resultmeasured

Claim · model-written summary

The authors interpreted the correlation as stimulation of bacterial growth by nematode grazing.

Interactor
nematodesNematodat1other
Outcome
stimulation of bacterial growthe0
Qualifier
grazinge0

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Brassica napus
Brassica napus · TaxonDidier Descouens · CC BY-SA 4.0 · Wikimedia Commons ↗

Verbatim

e0

“indicating stimulation of bacterial growth by the grazing”

✓ located verbatim in the source · abstract, characters 1088–1145 · show in text ↑
t0

“rape”

✓ located verbatim in the source · title, characters 68–72 · show in text ↑
t1

“nematodes”

✓ located verbatim in the source · title, characters 38–47 · show in text ↑

inoculation · molecular: metabolites · Brassica napus (oilseed rape)Positive and negative results

14 papers: 11 positive, 3 negative or no effect

2 papers in the same direction as this paper · 11 in the opposite direction

  1. positive
  2. positive
  3. positive

10 papers more in this group

See all 14 papers →

inoculation · quality: sugar starch · Brassica napus (oilseed rape)Results agree

2 papers: 0 positive, 2 negative or no effect

1 paper in the same direction as this paper

  1. negative
See all 2 papers →

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.