Abstract
The application of agricultural practices in which non-leguminous plants are inoculated with growth-promoting diazotrophic bacteria is gaining importance worldwide. Nevertheless, an efficient strategy for using this inoculation technology is still lacking, and a better comprehension of the environmental factors that influence a plant’s ability to support its associative bacterial community is indispensable to achieving standardized inoculation responses. To address the effects of nitrogen (N)-fertilization on the diversity of both the total and metabolically active endophytic bacterial communities of field-grown maize plants, we extracted total DNA and RNA from maize plants inoculated with Azospirillum brasilense strain Ab-V5 that were growing in Oxisol and treated with regular and low levels of N-fertilizers (RN and LN, respectively). Four clonal libraries were constructed and sequenced and the dominant populations analyzed. Partial description of the bacterial diversity indicated that plants receiving RN- and LN-treatments can maintain bacterial communities with similar diversity indexes for the total endophytic bacterial community, although the communities of Novosphingobium and Methylobacterium were unevenly distributed. Fertilization management had a stronger effect on the dominant populations of the metabolically active bacterial community, and 16S rRNA gene libraries from RN plants suggested a lower diversity of such populations in comparison with libraries from LN plants. The agronomic parameters obtained at the end of the crop season indicated that the inoculation treatment was efficient in promoting plant growth. However, the combination of regular treatments with N-fertilizers and plant inoculation did not have an additive effect and actually tended to decrease crop productivity.
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Claims 7
Claim · model-written summary
Regular and low nitrogen treatments maintained similar total endophyte diversity indexes.
- Treatment
- RN- and LN-treatmentse0
- Interactor
- bacterial communitiese0other
- Outcome
- diversity indexes for the total endophytic bacterial communitye0
- Direction
- similare0
Zea maysNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“plants receiving RN- and LN-treatments can maintain bacterial communities with similar diversity indexes for the total endophytic bacterial community”
t0“maize”
Claim · model-written summary
Novosphingobium and Methylobacterium were unevenly distributed across nitrogen treatments.
- Interactor
- Novosphingobium and MethylobacteriumMethylobacteriumNovosphingobiume0other
- Outcome
- unevenly distributede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“although the communities of Novosphingobium and Methylobacterium were unevenly distributed”
t0“maize”
Claim · model-written summary
Fertilization management more strongly affected dominant active endophyte populations.
- Treatment
- Fertilization managemente0
- Interactor
- bacterial communitye0other
- Outcome
- dominant populations of the metabolically active bacterial communitye0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Fertilization management had a stronger effect on the dominant populations of the metabolically active bacterial community”
t0“maize”
Claim · model-written summary
Regular nitrogen plants suggested lower active bacterial diversity than low nitrogen plants.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“16S rRNA gene libraries from RN plants suggested a lower diversity of such populations in comparison with libraries from LN plants”
t0“maize”
Claim · model-written summary
Inoculation promoted maize growth.
- Treatment
- inoculation treatmente0
- Interactor
- Azospirillum brasilense
Azospirillum brasilenset0symbiont - Outcome
- plant growthe0
- Direction
- promotinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the inoculation treatment was efficient in promoting plant growth”
t0“field-grown maize plants inoculated with Azospirillum brasilense”
Claim · model-written summary
Regular nitrogen fertilization combined with inoculation had no additive effect.
- Treatment
- combination of regular treatments with N-fertilizers and plant inoculatione0
- Interactor
- Azospirillum brasilenseAzospirillum brasilenset0symbiont
- Outcome
- additive effecte0
- Direction
- did not havee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the combination of regular treatments with N-fertilizers and plant inoculation did not have an additive effect”
t0“field-grown maize plants inoculated with Azospirillum brasilense”
Claim · model-written summary
Regular nitrogen fertilization with inoculation tended to decrease crop productivity.
- Treatment
- combination of regular treatments with N-fertilizers and plant inoculatione0
- Interactor
- Azospirillum brasilenseAzospirillum brasilenset0symbiont
- Outcome
- crop productivitye0
- Direction
- decreasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the combination of regular treatments with N-fertilizers and plant inoculation did not have an additive effect and actually tended to decrease crop productivity”
t0“field-grown maize plants inoculated with Azospirillum brasilense”
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inoculation · Azospirillum brasilense · Zea mays (maize)Results differ
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See all 6 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.