Abstract
Biological nitrogen fixation by rhizobia-nodulated legumes reduces the dependence on synthetic nitrogen fertilizers. Identification of locally adapted rhizobia may uncover economically valuable strains for sustainable agriculture. This study investigated the diversity and symbiotic potential of rhizobia associated with three Medicago species from Eastern Romania’s ecosystems. Phenotypic screening ensured that only rhizobial species were retained for molecular characterization. 16S rDNA sequencing clustered the isolates into four distinct groups: Sinorhizobium meliloti, Sinorhizobium medicae, Rhizobium leguminosarum, and Mesorhizobium spp. The chromosomal genes (atpD, glnII, recA) and nifH phylogenies were congruent, while the nodA phylogeny grouped the Mesorhizobium spp. isolates with R. leguminosarum. Medicago sativa was the most sampled plant species, and only S. meliloti and R. leguminosarum were found in its nodules, while Medicago falcata nodules hosted S. meliloti and Mesorhizobium spp. Medicago lupulina was the only species that hosted all four identified rhizobial groups, including S. medicae. This study provides the first report on the Mesorhizobium spp. associated with M. falcata nodules. Additionally, R. leguminosarum and two Mesorhizobium genospecies were identified as novel symbionts for Medicago spp. Comparative analysis of Medicago-associated rhizobia from other studies revealed that differences in 16S rDNA sequence type composition were influenced by Medicago species identity rather than geographic region.
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Claims 9
Claim · model-written summary
16S rDNA sequencing clustered the rhizobial isolates into four distinct groups.
- Interactor
- Sinorhizobium meliloti
Sinorhizobium melilotie1symbiont - Second interactor
- Mesorhizobium spp.
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Mesorhizobiume1symbiont - Outcome
- four distinct groupse1
MedicagoOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
t0“Nodules of Medicago spp.”
e1“16S rDNA sequencing clustered the isolates into four distinct groups: Sinorhizobium meliloti, Sinorhizobium medicae, Rhizobium leguminosarum, and Mesorhizobium spp.”
Claim · model-written summary
Medicago sativa nodules contained only S. meliloti and R. leguminosarum.
- Taxon
- Medicago sativa
Medicago sativae2 - Interactor
- S. melilotiSinorhizobium melilotie2symbiont
- Second interactor
- R. leguminosarum
Rhizobium leguminosarume2symbiont - Outcome
- found in its nodulese2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“Medicago sativa was the most sampled plant species, and only S. meliloti and R. leguminosarum were found in its nodules”
Claim · model-written summary
Medicago falcata nodules hosted S. meliloti and Mesorhizobium spp.
- Taxon
- Medicago falcata
Medicago sativa subsp. falcatae3 - Interactor
- S. melilotiSinorhizobium melilotie3symbiont
- Second interactor
- Mesorhizobium spp.Mesorhizobiume3symbiont
- Outcome
- nodules hostede3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e3“while Medicago falcata nodules hosted S. meliloti and Mesorhizobium spp.”
Claim · model-written summary
Medicago lupulina was the only species whose nodules hosted all four rhizobial groups, including S. medicae.
- Taxon
- Medicago lupulina
Medicago lupulinae4 - Interactor
- S. medicae
Sinorhizobium medicaee4symbiont - Outcome
- hosted all four identified rhizobial groupse4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e4“Medicago lupulina was the only species that hosted all four identified rhizobial groups, including S. medicae”
Claim · model-written summary
This study is the first report of Mesorhizobium spp. associated with M. falcata nodules.
- Taxon
- M. falcataMedicago sativa subsp. falcatae5
- Interactor
- Mesorhizobium spp.Mesorhizobiume5symbiont
- Outcome
- first reporte5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“This study provides the first report on the Mesorhizobium spp. associated with M. falcata nodules”
Claim · model-written summary
R. leguminosarum and two Mesorhizobium genospecies were identified as novel symbionts of Medicago spp.
- Interactor
- R. leguminosarumRhizobium leguminosarume6symbiont
- Second interactor
- Mesorhizobium genospeciese6symbiont
- Outcome
- novel symbiontse6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e6“R. leguminosarum and two Mesorhizobium genospecies were identified as novel symbionts for Medicago spp.”
Claim · model-written summary
Differences in 16S rDNA sequence type composition were associated with Medicago species identity rather than geographic region.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e7“differences in 16S rDNA sequence type composition were influenced by Medicago species identity rather than geographic region”
Claim · model-written summary
Phylogenies of the chromosomal genes atpD, glnII and recA and of nifH were congruent.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Nodules of Medicago spp.”
e0“The chromosomal genes (atpD, glnII, recA) and nifH phylogenies were congruent, while the nodA phylogeny grouped the Mesorhizobium spp. isolates with R. leguminosarum”
Claim · model-written summary
The nodA phylogeny grouped Mesorhizobium spp. isolates with R. leguminosarum.
- Interactor
- Mesorhizobium spp.Mesorhizobiume0symbiont
- Second interactor
- R. leguminosarumRhizobium leguminosarume0symbiont
- Gene
- nodAe0
- Outcome
- grouped the Mesorhizobium spp. isolates with R. leguminosarume0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Nodules of Medicago spp.”
e0“The chromosomal genes (atpD, glnII, recA) and nifH phylogenies were congruent, while the nodA phylogeny grouped the Mesorhizobium spp. isolates with R. leguminosarum”