Abstract
Phaseolus vulgaris (common bean) is nodulated by diverse Rhizobium species. Although Ecuador is recognized as one of the centers of bean diversification, its native rhizobial diversity and geographic distribution remains poorly characterized. We isolated 46 native Rhizobium strains from root nodules across four Andean provinces (Imbabura, Pichincha, Chimborazo, and Loja). Partial sequencing of the recA gene delineated nine strain clusters (R1-R9) within two major phylogenetic groups: (i) Rhizobium ecuadorense/Rhizobium leguminosarum/Rhizobium etli/Rhizobium phaseoli and (ii) R. tropici. Multilocus sequence analysis (MLSA) of the housekeeping genes recA, glnII, dnaK genes from 19 representative isolates showed four phylogenetic clusters (C1-C4). Cluster C1 (R. ecuadorense-related) predominated in northern Ecuador; C2 formed a distinct Chimborazo cluster; C3 appeared sporadically in Imbabura and Chimborazo; and C4 (R. tropici-related) was confined to Loja's Amotape-Huancabamba Zone and displayed unique phenotypes. In greenhouse assays on two local bean varieties, all isolates formed nodules in both varieties; several isolates induced significantly higher nodule counts than the commercial inoculant UMR1899 (Rhizobium tropici IIB CIAT 899T). These results suggest geographic variation among Ecuadorian Rhizobium populations and identify locally predominant groups for further evaluation as bioinoculants.
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Claims 9
Claim · model-written summary
Forty-six native Rhizobium strains were isolated from bean root nodules.
- Taxon
- common bean
Phaseolus vulgarist0 - Outcome
- 46 native Rhizobium strainse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“We isolated 46 native Rhizobium strains from root nodules across four Andean provinces”
t0“Rhizobium diversity associated with common bean cultivars”
Claim · model-written summary
recA sequencing delineated nine strain clusters in two phylogenetic groups.
- Taxon
- common beanPhaseolus vulgarist0
- Gene
- recAe0
- Outcome
- nine strain clusters (R1-R9) within two major phylogenetic groupse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Partial sequencing of the recA gene delineated nine strain clusters (R1-R9) within two major phylogenetic groups”
t0“Rhizobium diversity associated with common bean cultivars”
Claim · model-written summary
Multilocus analysis identified four phylogenetic clusters.
- Taxon
- common beanPhaseolus vulgarist0
- Outcome
- four phylogenetic clusters (C1-C4)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“showed four phylogenetic clusters (C1-C4)”
t0“Rhizobium diversity associated with common bean cultivars”
Claim · model-written summary
Cluster C1 predominated in northern Ecuador.
- Taxon
- common beanPhaseolus vulgarist0
- Interactor
- R. ecuadorenseRhizobium ecuadorensee0symbiont
- Outcome
- Cluster C1 (R. ecuadorense-related)e0
- Setting
- northern Ecuadore0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cluster C1 (R. ecuadorense-related) predominated in northern Ecuador”
t0“Rhizobium diversity associated with common bean cultivars”
Claim · model-written summary
C2 formed a distinct Chimborazo cluster.
- Taxon
- common beanPhaseolus vulgarist0
- Outcome
- distinct Chimborazo clustere0
- Setting
- Chimborazoe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“C2 formed a distinct Chimborazo cluster”
t0“Rhizobium diversity associated with common bean cultivars”
Claim · model-written summary
C3 appeared sporadically in Imbabura and Chimborazo.
- Taxon
- common beanPhaseolus vulgarist0
- Outcome
- C3 appeared sporadicallye0
- Setting
- Imbabura and Chimborazoe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“C3 appeared sporadically in Imbabura and Chimborazo”
t0“Rhizobium diversity associated with common bean cultivars”
Claim · model-written summary
C4 was confined to Loja and showed unique phenotypes.
- Taxon
- common beanPhaseolus vulgarist0
- Interactor
- R. tropici
Martinezella tropicie0symbiont - Outcome
- unique phenotypese0
- Setting
- Loja's Amotape-Huancabamba Zonee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“C4 (R. tropici-related) was confined to Loja's Amotape-Huancabamba Zone and displayed unique phenotypes”
t0“Rhizobium diversity associated with common bean cultivars”
Claim · model-written summary
All isolates formed nodules in both tested bean varieties.
- Taxon
- common beanPhaseolus vulgarist0
- Outcome
- nodulese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“all isolates formed nodules in both varieties”
t0“Rhizobium diversity associated with common bean cultivars”
Claim · model-written summary
Several isolates induced significantly more nodules than the commercial inoculant.
- Taxon
- common beanPhaseolus vulgarist0
- Treatment
- several isolatese0
- Interactor
- Rhizobium tropici IIB CIAT 899TMartinezella tropicie0symbiont
- Outcome
- nodule countse0
- Direction
- highere0
- Comparator
- commercial inoculant UMR1899e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“several isolates induced significantly higher nodule counts than the commercial inoculant UMR1899 (Rhizobium tropici IIB CIAT 899T)”
t0“Rhizobium diversity associated with common bean cultivars”