Abstract
The diversities leaf-associated bacteria on nonnodulated (Nod(-)), wild-type nodulated (Nod(+)), and hypernodulated (Nod(++)) soybeans were evaluated by clone library analyses of the 16S rRNA gene. To analyze the impact of nitrogen fertilization on the bacterial leaf community, soybeans were treated with standard nitrogen (SN) (15 kg N ha(-1)) or heavy nitrogen (HN) (615 kg N ha(-1)) fertilization. Under SN fertilization, the relative abundance of Alphaproteobacteria was significantly higher in Nod(-) and Nod(++) soybeans (82% to 96%) than in Nod(+) soybeans (54%). The community structure of leaf-associated bacteria in Nod(+) soybeans was almost unaffected by the levels of nitrogen fertilization. However, differences were visible in Nod(-) and Nod(++) soybeans. HN fertilization drastically decreased the relative abundance of Alphaproteobacteria in Nod(-) and Nod(++) soybeans (46% to 76%) and, conversely, increased those of Gammaproteobacteria and Firmicutes in these mutant soybeans. In the Alphaproteobacteria, cluster analyses identified two operational taxonomic units (OTUs) (Aurantimonas sp. and Methylobacterium sp.) that were especially sensitive to nodulation phenotypes under SN fertilization and to nitrogen fertilization levels. Arbuscular mycorrhizal infection was not observed on the root tissues examined, presumably due to the rotation of paddy and upland fields. These results suggest that a subpopulation of leaf-associated bacteria in wild-type Nod(+) soybeans is controlled in similar ways through the systemic regulation of autoregulation of nodulation, which interferes with the impacts of N levels on the bacterial community of soybean leaves.
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Claims 9
Claim · model-written summary
Under standard nitrogen, Alphaproteobacteria were more abundant in nonnodulated and hypernodulated soybeans than wild type.
- Taxon
- soybeans
Glycine maxe0 - Material
- Nod(-) and Nod(++)e0
- Interactor
- AlphaproteobacteriaAlphaproteobacteriae0other
- Outcome
- relative abundance of Alphaproteobacteriae0
- Direction
- highere0
- Value
- 82% to 96%e0
- Qualifier
- 54%e0
- Comparator
- Nod(+) soybeanse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Under SN fertilization, the relative abundance of Alphaproteobacteria was significantly higher in Nod(-) and Nod(++) soybeans (82% to 96%) than in Nod(+) soybeans (54%).”
Claim · model-written summary
Wild-type soybean leaf bacterial structure was almost unaffected by nitrogen level.
- Taxon
- soybeansGlycine maxe0
- Material
- Nod(+)e0
- Treatment
- levels of nitrogen fertilizatione0
- Outcome
- community structure of leaf-associated bacteriae0
- Direction
- almost unaffectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The community structure of leaf-associated bacteria in Nod(+) soybeans was almost unaffected by the levels of nitrogen fertilization.”
Claim · model-written summary
Nitrogen levels altered leaf bacterial communities in nonnodulated and hypernodulated soybeans.
- Taxon
- soybeansGlycine maxe0
- Material
- Nod(-) and Nod(++)e0
- Treatment
- nitrogen fertilizationt0
- Outcome
- community structure of leaf-associated bacteriat1
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“However, differences were visible in Nod(-) and Nod(++) soybeans.”
t0“To analyze the impact of nitrogen fertilization on the bacterial leaf community”
t1“community structure of leaf-associated bacteria”
Claim · model-written summary
Heavy nitrogen decreased Alphaproteobacteria abundance in mutant soybeans.
- Taxon
- soybeansGlycine maxe0
- Material
- Nod(-) and Nod(++)e0
- Treatment
- HN fertilizatione0
- Interactor
- AlphaproteobacteriaAlphaproteobacteriae0other
- Outcome
- relative abundance of Alphaproteobacteriae0
- Direction
- decreasede0
- Value
- 46% to 76%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“HN fertilization drastically decreased the relative abundance of Alphaproteobacteria in Nod(-) and Nod(++) soybeans (46% to 76%)”
Claim · model-written summary
Heavy nitrogen increased Gammaproteobacteria abundance in mutant soybeans.
- Taxon
- soybeansGlycine maxe0
- Treatment
- HN fertilizationt0
- Interactor
- GammaproteobacteriaGammaproteobacteriae0other
- Outcome
- Gammaproteobacteriae0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increased those of Gammaproteobacteria and Firmicutes in these mutant soybeans.”
t0“HN fertilization”
Claim · model-written summary
Heavy nitrogen increased Firmicutes abundance in mutant soybeans.
- Taxon
- soybeansGlycine maxe0
- Treatment
- HN fertilizationt0
- Outcome
- Firmicutese0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increased those of Gammaproteobacteria and Firmicutes in these mutant soybeans.”
t0“HN fertilization”
Claim · model-written summary
Aurantimonas sp. OTU responded especially to nodulation phenotype and nitrogen level.
- Taxon
- soybeansGlycine maxt0
- Interactor
- Aurantimonas sp.Aurantimonase0other
- Outcome
- Aurantimonas sp.e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“two operational taxonomic units (OTUs) (Aurantimonas sp. and Methylobacterium sp.) that were especially sensitive to nodulation phenotypes under SN fertilization and to nitrogen fertilization levels.”
t0“and hypernodulated (Nod(++)) soybeans”
Claim · model-written summary
Methylobacterium sp. OTU responded especially to nodulation phenotype and nitrogen level.
- Taxon
- soybeansGlycine maxt0
- Interactor
- Methylobacterium sp.Methylobacteriume0other
- Outcome
- Methylobacterium sp.e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“two operational taxonomic units (OTUs) (Aurantimonas sp. and Methylobacterium sp.) that were especially sensitive to nodulation phenotypes under SN fertilization and to nitrogen fertilization levels.”
t0“and hypernodulated (Nod(++)) soybeans”
Claim · model-written summary
Arbuscular mycorrhizal infection was absent from examined roots.
- Taxon
- soybeansGlycine maxt0
- Organ / stage
- root tissuese0
- Interactor
- Arbuscular mycorrhizale0symbiont
- Outcome
- Arbuscular mycorrhizal infection was not observede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Arbuscular mycorrhizal infection was not observed on the root tissues examined”
t0“and hypernodulated (Nod(++)) soybeans”