A plant-guided soybean rhizosphere SynCom selected through iterative chlorophyll-based microbiome engineering to improve nodulation and biomass in soil.
Taxonomy
| Taxon | Ontology ID | Functional Roles | Abundance |
|---|---|---|---|
| soybean rhizosphere bacterial SynCom members — ontology label: Bacteria | NCBITaxon:2 · TaxonMech · TraitMech |
CROSS_FEEDER
|
N/A |
|
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| Bradyrhizobium | NCBITaxon:374 · TaxonMech · TraitMech |
NITROGEN_FIXING_SYMBIONT
|
N/A |
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Ecological Interactions
The graph shows only explicitly linked interaction participants. Community members without an asserted participant link are omitted; membership alone does not imply an interaction.
Nodule-Associated Bradyrhizobium Genotype Pattern
Nodule-isolate fingerprints and marker evidence were consistent with B. diazoefficiens-like genotypes during recurrent selection. The source interprets this pattern as selection but also notes an early pattern before selection and unresolved pressures. This observation does not establish reciprocal fitness benefits, quantify nitrogen-fixation flux or isolate the genotype pattern as the cause of later plant phenotypes.
Participating Taxa: Bradyrhizobium
Biological Processes:
- nodulation (GO:0009877 · PathwayMech)
Evidence
-
PMID:42007760 - PARTIAL (IN_VIVO)"Taken together, these results suggest that selective pressures during recurrent selection of plants with high leaf chlorophyll contents favored B. diazoefficiens genotypes within the nodulating population."
Rhizosphere Community Composition Across Selection Rounds
Rhizosphere profiles shifted from initial Bacillus-related dominance toward greater relative representation of Pseudomonadales, Burkholderiales and Sphingomonadales and reduced Rhizobiales representation. This is community-composition evidence, not demonstrated niche partitioning, microbial cooperation or IAA/siderophore-mediated succession. Co-occurrence and inferred functions do not establish those mechanisms.
Evidence
-
PMID:42007760 - SUPPORT (IN_VIVO)"increased representation of Pseudomonadales, Burkholderiales, and Sphingomonadales at the expense of Rhizobiales"
HR6 Nonsterile-Soil Plant Phenotypes
In non-sterile-soil pots, the Results report higher HR6+HN6 nodule number, total nodule dry weight and shoot dry weight. Table 1 gives higher means but shared significance letters with both the uninoculated and E109 controls for these three endpoints; this is not uniformly significant superiority over both controls. Chlorophyll content did not differ among treatments. These are host phenotypes, not field deployment, direct nitrogen-fixation flux, reciprocal microbial fitness benefits or proof that a selected genotype caused the response.
Biological Processes:
- nodulation (GO:0009877 · PathwayMech)
Evidence
-
PMID:42007760 - PARTIAL (IN_VIVO)"HR6 promoted higher nodule number, nodule dry weight, and shoot dry weight"
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PMID:42007760 - SUPPORT (IN_VIVO)"The SynComs HR6 and HR8 were evaluated in pots filled with non-sterile soil from the UNLP experimental field at Los Hornos"
Knowledge gaps & discussions (1)
KNOWLEDGE_GAP OPEN Which mechanisms explain the genotype and composition patterns, and what comparator effects are supported for HR6+HN6?
Three assembly/formulation arrows are removed; the previously pruned rhizosphere-to-HR6 arrow remains absent. The primary discussion leaves selection pressures unresolved, and co-occurrence/functional inference do not identify a mediator. For nodule number, total nodule dry weight and shoot dry weight, Table 1 shares significance letters between HR6+HN6 and both controls despite the narrative of higher values. Retain the reported means without blanket significance or field efficacy claims. Raw data and supplementary figures were not reanalyzed; candidate trait assays and non-graph roles are not recertified (#1821; related role queue #497).
Attaches to: ecological_interactions#Nodule-Associated Bradyrhizobium Genotype Pattern, ecological_interactions#Rhizosphere Community Composition Across Selection Rounds, ecological_interactions#HR6 Nonsterile-Soil Plant Phenotypes
1 evidence item(s)
unknown selection pressures seemed to shape the genotypic structure of the soybean-nodulating bradyrhizobial population at a rate faster than previously estimated.
The source leaves the selection mechanism unresolved.
Environmental Factors
| Factor | Value | Unit |
|---|---|---|
| chlorophyll-guided recurrent selection | Rhizosphere communities from superior soybean performers were pooled and propagated across selection rounds. | N/A |
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Growth Media
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