Abstract
Diazotrophic bacteria can reduce N2 into plant-available ammonium (NH4+), promoting plant growth and reducing nitrogen (N) fertilizer requirements. However, there are few systematic studies on the effects of diazotrophic bacteria on biological N2 fixation (BNF) contribution rate and host plant N uptake and metabolism. In this study, the interactions of the diazotrophic Paenibacillus beijingensis BJ-18 with wheat, maize and cucumber were investigated when it was inoculated to these plant seedlings grown in both low N and high N soils, with un-inoculated plants as controls. This study showed that GFP-tagged P. beijingensis BJ-18 colonized inside and outside seedlings, forming rhizospheric and endophytic colonies in roots, stems and leaves. The numbers of this bacterium in the inoculated plants depended on soil N levels. Under low N, inoculation significantly increased shoot dry weight (wheat 86.1%, maize 46.6% and cucumber 103.6%) and root dry weight (wheat 46.0%, maize 47.5% and cucumber 20.3%). The 15N-isotope-enrichment experiment indicated that plant seedlings derived 12.9%-36.4% N from BNF. The transcript levels of nifH in the inoculated plants were 0.75-1.61 folds higher in low N soil than those in high N soil. Inoculation enhanced NH4+ and nitrate (NO3-) uptake from soil especially under low N. The total N in the inoculated plants were increased by 49.1%-92.3% under low N and by 13%-15.5% under high N. Inoculation enhanced activities of glutamine synthetase (GS) and nitrate reductase (NR) in plants, especially under low N. The expression levels of N uptake and N metabolism genes: AMT (ammonium transporter), NRT (nitrate transporter), NiR (nitrite reductase), NR, GS and GOGAT (glutamate synthase) in the inoculated plants grown under low N were up-regulated 1.5-91.9 folds, but they were not obviously changed under high N. Taken together, P. beijingensis BJ-18 was an effective, endophytic and diazotrophic bacterium. This bacterium contributed to plants with fixed N2, promoted plant growth and N uptake, and enhanced gene expression and enzyme activities involved in N uptake and assimilation in plants. However, these positive effects on plants were regulated by soil N status. This study might provide insight into the interactions of plants with beneficial associative and endophytic diazotrophic bacteria.
Abstract from the paper’s OpenAlex record; open copy licensed cc-by. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 15
Claim · model-written summary
The bacterium colonized seedlings internally and externally.
- Taxon
- wheat, maize and cucumber
Cucumis sativus
Triticum aestivum
Zea mayse1 - Interactor
- P. beijingensis BJ-18Paenibacillus beijingensise0symbiont
- Outcome
- colonized inside and outside seedlingse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“GFP-tagged P. beijingensis BJ-18 colonized inside and outside seedlings, forming rhizospheric and endophytic colonies in roots, stems and leaves.”
e1“wheat, maize and cucumber”
Claim · model-written summary
Bacterial numbers depended on soil nitrogen.
- Taxon
- wheat, maize and cucumberCucumis sativusTriticum aestivumZea mayse1
- Treatment
- soil N levelse0
- Outcome
- numbers of this bacteriume0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The numbers of this bacterium in the inoculated plants depended on soil N levels.”
e1“wheat, maize and cucumber”
Claim · model-written summary
Under low nitrogen, inoculation increased maize shoot dry weight by 46.6%.
- Treatment
- inoculatione1
- Outcome
- shoot dry weighte1
- Direction
- increasede1
- Value
- 46.6%e0
- Comparator
- un-inoculated plantse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“maize 46.6%”
e1“Under low N, inoculation significantly increased shoot dry weight (wheat 86.1%, maize 46.6% and cucumber 103.6%) and root dry weight (wheat 46.0%, maize 47.5% and cucumber 20.3%).”
e2“the interactions of the diazotrophic Paenibacillus beijingensis BJ-18 with wheat, maize and cucumber were investigated when it was inoculated to these plant seedlings grown in both low N and high N soils, with un-inoculated plants as controls.”
Claim · model-written summary
Under low nitrogen, inoculation increased cucumber shoot dry weight by 103.6%.
- Taxon
- cucumberCucumis sativuse0
- Treatment
- inoculatione1
- Outcome
- shoot dry weighte1
- Direction
- increasede1
- Value
- 103.6%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“cucumber 103.6%”
e1“Under low N, inoculation significantly increased shoot dry weight (wheat 86.1%, maize 46.6% and cucumber 103.6%) and root dry weight (wheat 46.0%, maize 47.5% and cucumber 20.3%).”
Claim · model-written summary
Under low nitrogen, inoculation increased wheat root dry weight by 46.0%.
- Taxon
- wheatTriticum aestivume0
- Treatment
- inoculatione1
- Outcome
- root dry weighte0
- Direction
- increasede1
- Value
- 46.0%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“root dry weight (wheat 46.0%”
e1“Under low N, inoculation significantly increased shoot dry weight (wheat 86.1%, maize 46.6% and cucumber 103.6%) and root dry weight (wheat 46.0%, maize 47.5% and cucumber 20.3%).”
Claim · model-written summary
Under low nitrogen, inoculation increased maize root dry weight by 47.5%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“maize 47.5%”
e1“Under low N, inoculation significantly increased shoot dry weight (wheat 86.1%, maize 46.6% and cucumber 103.6%) and root dry weight (wheat 46.0%, maize 47.5% and cucumber 20.3%).”
Claim · model-written summary
Under low nitrogen, inoculation increased cucumber root dry weight by 20.3%.
- Taxon
- cucumberCucumis sativuse0
- Treatment
- inoculatione1
- Outcome
- root dry weighte1
- Direction
- increasede1
- Value
- 20.3%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“cucumber 20.3%”
e1“Under low N, inoculation significantly increased shoot dry weight (wheat 86.1%, maize 46.6% and cucumber 103.6%) and root dry weight (wheat 46.0%, maize 47.5% and cucumber 20.3%).”
Claim · model-written summary
Seedlings obtained 12.9%-36.4% of nitrogen from biological nitrogen fixation.
- Taxon
- wheat, maize and cucumberCucumis sativusTriticum aestivumZea mayse1
- Outcome
- N from BNFe0
- Value
- 12.9%-36.4% Ne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“plant seedlings derived 12.9%-36.4% N from BNF”
e1“wheat, maize and cucumber”
Claim · model-written summary
Low soil nitrogen produced higher nifH transcript levels in inoculated plants than high nitrogen.
- Taxon
- wheat, maize and cucumberCucumis sativusTriticum aestivumZea mayse1
- Gene
- nifHe0
- Outcome
- transcript levels of nifHe0
- Direction
- highere0
- Value
- 0.75-1.61 foldse0
- Comparator
- high N soile0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The transcript levels of nifH in the inoculated plants were 0.75-1.61 folds higher in low N soil than those in high N soil.”
e1“wheat, maize and cucumber”
Claim · model-written summary
Inoculation enhanced ammonium and nitrate uptake, especially under low nitrogen.
- Taxon
- wheat, maize and cucumberCucumis sativusTriticum aestivumZea mayse1
- Treatment
- Inoculatione0
- Outcome
- NH4+ and nitrate (NO3-) uptakee0
- Direction
- enhancede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Inoculation enhanced NH4+ and nitrate (NO3-) uptake from soil especially under low N.”
e1“wheat, maize and cucumber”
Claim · model-written summary
Inoculation increased total plant nitrogen by 49.1%-92.3% under low nitrogen.
- Taxon
- wheat, maize and cucumberCucumis sativusTriticum aestivumZea mayse1
- Treatment
- inoculatede0
- Outcome
- total Ne0
- Direction
- increasede0
- Value
- 49.1%-92.3%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The total N in the inoculated plants were increased by 49.1%-92.3% under low N”
e1“wheat, maize and cucumber”
Claim · model-written summary
Inoculation increased total plant nitrogen by 13%-15.5% under high nitrogen.
- Taxon
- wheat, maize and cucumberCucumis sativusTriticum aestivumZea mayse2
- Treatment
- inoculatede1
- Outcome
- total Ne1
- Direction
- increasede1
- Value
- 13%-15.5%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“by 13%-15.5% under high N”
e1“The total N in the inoculated plants were increased by 49.1%-92.3% under low N and by 13%-15.5% under high N.”
e2“wheat, maize and cucumber”
Claim · model-written summary
Inoculation enhanced glutamine synthetase and nitrate reductase activity.
- Taxon
- wheat, maize and cucumberCucumis sativusTriticum aestivumZea mayse1
- Treatment
- Inoculatione0
- Outcome
- activities of glutamine synthetase (GS) and nitrate reductase (NR)e0
- Direction
- enhancede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Inoculation enhanced activities of glutamine synthetase (GS) and nitrate reductase (NR) in plants, especially under low N.”
e1“wheat, maize and cucumber”
Claim · model-written summary
Nitrogen uptake and metabolism gene expression rose under low nitrogen.
- Taxon
- wheat, maize and cucumberCucumis sativusTriticum aestivumZea mayse1
- Treatment
- inoculatede0
- Outcome
- expression levels of N uptake and N metabolism genese0
- Direction
- up-regulatede0
- Value
- 1.5-91.9 foldse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The expression levels of N uptake and N metabolism genes: AMT (ammonium transporter), NRT (nitrate transporter), NiR (nitrite reductase), NR, GS and GOGAT (glutamate synthase) in the inoculated plants grown under low N were up-regulated 1.5-91.9 folds”
e1“wheat, maize and cucumber”
Claim · model-written summary
These gene expression levels were not obviously changed under high nitrogen.
- Taxon
- wheat, maize and cucumberCucumis sativusTriticum aestivumZea mayse2
- Treatment
- inoculatede1
- Outcome
- expression levels of N uptake and N metabolism genese1
- Direction
- not obviously changede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“but they were not obviously changed under high N.”
e1“The expression levels of N uptake and N metabolism genes: AMT (ammonium transporter), NRT (nitrate transporter), NiR (nitrite reductase), NR, GS and GOGAT (glutamate synthase) in the inoculated plants grown under low N were up-regulated 1.5-91.9 folds, but they were not obviously changed under high N.”
e2“wheat, maize and cucumber”
The same questions in other papers
inoculation · molecular: expression · Cucumis sativus (cucumber)Positive and negative results
12 papers in the same direction as this paper · 5 in the opposite direction
- no effect
- negative
- no effect
14 papers more in this group
See all 18 papers →inoculation · molecular: expression · Zea mays (maize)Positive and negative results
19 papers in the same direction as this paper · 5 in the opposite direction
- no effect
- negative
- no effect
21 papers more in this group
See all 25 papers →inoculation · nutrient: content · Cucumis sativus (cucumber)Positive and negative results
27 papers in the same direction as this paper · 3 in the opposite direction
- negative
- negative
- negative
27 papers more in this group
See all 31 papers →inoculation · physiology: enzyme activity · Triticum aestivum (wheat)Positive and negative results
28 papers in the same direction as this paper · 2 in the opposite direction
- positive
- negative
- no effect
27 papers more in this group
See all 31 papers →inoculation · molecular: expression · Triticum aestivum (wheat)Positive and negative results
37 papers in the same direction as this paper · 9 in the opposite direction
- positive
- no effect
- no effect
43 papers more in this group
See all 47 papers →inoculation · growth · Cucumis sativus (cucumber)Positive and negative results
108 papers in the same direction as this paper · 12 in the opposite direction
- positive
- positive
- negative
117 papers more in this group
See all 121 papers →inoculation · nutrient: content · Triticum aestivum (wheat)Positive and negative results
262 papers in the same direction as this paper · 13 in the opposite direction · 1 reporting no difference from an alternative
- positive
- no effect
- no effect
273 papers more in this group
See all 277 papers →inoculation · nutrient: content · Zea mays (maize)Positive and negative results
287 papers in the same direction as this paper · 16 in the opposite direction · 2 reporting no difference from an alternative
- no effect
- no effect
- no effect
302 papers more in this group
See all 306 papers →8 of 12 groups shown: named compounds and organisms first, then groups whose results differ (checked claim by claim), then those with positive and negative results, then the smaller groups.
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.