Abstract
Low phosphorus soils are thought to constitute the majority of soils worldwide and cannot support intensive agriculture without high fertilizer inputs. Rhizospheric Rhizobacteria are well-known to modify P dynamics, and an increased bacterial diversity normally has a positive impact on process rate. However, it is not well known how variation in bacterial diversity at the subspecies level could influence trophic interactions in the rhizosphere and its consequences on plant P nutrition. We therefore hypothesized that the interactions between closely related P solubilizing bacteria and their grazing nematodes could improve plant P dynamics from an unavailable P source. We isolated four Pseudomonas poae strains and extracted nematodes from a Saskatchewan wheat field soil sample. The potential of all bacterial isolates and with and without nematodes combinations for increasing P availability in the wheat rhizosphere was tested in controlled microcosms with Ca3(PO4)2 as sole P source. Liberated P, phosphatase activity, plant P and bacterial abundance based upon phnX gene copies were determined. Phosphorus solubilization efficiency of isolates varied as P. poae 1 >P. poae 2 > P. poae 3 > P. poae 4, respectively whereas phosphatase enzyme activity was only detected under nematodes grazing and during the first 15 days of the experiment. Nematodes grazing upon individual Pseudomonas poae increased phosphatase enzyme activity, bacterial abundance, but decreased plant P concentration compared to non-grazed system. In contrast, the treatment combining all Pseudomonas poae isolates together with nematodes resulted in significant increases in P availability and plant P concentration. Diverse P-solubilizing efficiency and interaction with nematodes within the same bacterial “species” suggest that P dynamics might be linked to micro variation in soil diversity that would not accurately be picked up using common tools such as 16S rRNA gene sequencing.
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Claims 7
Claim · model-written summary
P solubilization efficiency ranked four P. poae isolates.
- Taxon
- Wheat
Triticum aestivumt0 - Interactor
- P. poaePseudomonas poaee0symbiont
- Outcome
- Phosphorus solubilization efficiency of isolatese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Phosphorus solubilization efficiency of isolates varied as P. poae 1 >P. poae 2 > P. poae 3 > P. poae 4”
t0“Wheat”
Claim · model-written summary
Phosphatase activity was detected only with nematode grazing in the first 15 days.
- Taxon
- WheatTriticum aestivumt0
- Outcome
- phosphatase enzyme activity was only detectede0
- Qualifier
- first 15 days of the experimente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“phosphatase enzyme activity was only detected under nematodes grazing and during the first 15 days of the experiment”
t0“Wheat”
Claim · model-written summary
Grazing on individual P. poae isolates increased phosphatase activity.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- Nematodes grazing upon individual Pseudomonas poaee0
- Interactor
- Pseudomonas poaePseudomonas poaee0symbiont
- Outcome
- phosphatase enzyme activitye0
- Direction
- increasede0
- Comparator
- non-grazed systeme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nematodes grazing upon individual Pseudomonas poae increased phosphatase enzyme activity, bacterial abundance, but decreased plant P concentration compared to non-grazed system”
t0“Wheat”
Claim · model-written summary
Grazing on individual P. poae isolates increased bacterial abundance.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- Nematodes grazing upon individual Pseudomonas poaee0
- Interactor
- Pseudomonas poaePseudomonas poaee0symbiont
- Outcome
- bacterial abundancee0
- Direction
- increasede0
- Comparator
- non-grazed systeme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nematodes grazing upon individual Pseudomonas poae increased phosphatase enzyme activity, bacterial abundance, but decreased plant P concentration compared to non-grazed system”
t0“Wheat”
Claim · model-written summary
Grazing on individual isolates decreased plant P concentration.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- Nematodes grazing upon individual Pseudomonas poaee0
- Interactor
- Pseudomonas poaePseudomonas poaee0symbiont
- Outcome
- plant P concentratione0
- Direction
- decreasede0
- Comparator
- non-grazed systeme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nematodes grazing upon individual Pseudomonas poae increased phosphatase enzyme activity, bacterial abundance, but decreased plant P concentration compared to non-grazed system”
t0“Wheat”
Claim · model-written summary
All P. poae isolates with nematodes significantly increased P availability.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- combining all Pseudomonas poae isolates together with nematodese0
- Interactor
- Pseudomonas poaePseudomonas poaee0symbiont
- Outcome
- P availabilitye0
- Direction
- increasese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the treatment combining all Pseudomonas poae isolates together with nematodes resulted in significant increases in P availability and plant P concentration”
t0“Wheat”
Claim · model-written summary
All P. poae isolates with nematodes significantly increased plant P concentration.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- combining all Pseudomonas poae isolates together with nematodese0
- Interactor
- Pseudomonas poaePseudomonas poaee0symbiont
- Outcome
- plant P concentratione0
- Direction
- increasese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the treatment combining all Pseudomonas poae isolates together with nematodes resulted in significant increases in P availability and plant P concentration”
t0“Wheat”
The same questions in other papers
grazing · nutrient: content · Triticum aestivum (wheat)Positive and negative results
1 paper in the same direction as this paper · 2 in the opposite direction
- positive
- positive
- no effect
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.