A five-isolate pepper rhizosphere SynCom that reduces Phytophthora capsici disease severity and enhances pepper growth.
Taxonomy
| Taxon | Ontology ID | Functional Roles | Abundance |
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| Bacillus sp. — ontology label: Bacillus <firmicutes> | NCBITaxon:1386 · TaxonMech · TraitMech | N/A | |
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| Flavobacterium sp. — ontology label: Flavobacterium | NCBITaxon:237 · TaxonMech · TraitMech | N/A | |
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| Cytobacillus firmus | NCBITaxon:1399 · TaxonMech · TraitMech | N/A | |
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| Streptomyces sp. | NCBITaxon:1931 · TaxonMech · TraitMech | N/A | |
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| Pseudomonas sp. | NCBITaxon:306 · TaxonMech · TraitMech | 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.
Individual-Isolate PGPR Trait Measurements
The five selected isolates showed distinct in-vitro PGPR trait profiles, including phosphate solubilization, IAA, siderophore and ammonia production and biofilm-associated assays. Preserve the positive screens without assigning every activity equally to every member. Table1 and narrative trait rankings differ, so the selection rationale does not establish a unique highest producer. These traits were assayed individually before assembly, not re-quantified in rhizosphere soil, and compatibility screens do not establish reciprocal fitness or synergistic trait expression.
Metabolites: phosphate (CHEBI:26020 · MediaIngredientMech · CMMMech), indole-3-acetic acid (CHEBI:16411 · MediaIngredientMech · CMMMech), siderophore (CHEBI:26672 · MediaIngredientMech · CMMMech)
HYPOTHESIZED - Nutrient-mobilization and phytohormone traits of the selected isolates could contribute to challenged-host growth. The traits were not re-quantified in soil and were not selectively perturbed, so the host comparison does not isolate their mediation.
Evidence
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PMID:40508300 - SUPPORT (IN_VITRO)"The SynCom members exhibited phosphate solubilization, indole-3-acetic acid production, catalase activity, siderophore synthesis, and strong antagonism against P. capsici"
Isolate Antagonism Against Phytophthora capsici
Individual dual-culture assays showed substantially stronger P. capsici inhibition by S. roseicoloratus T14 and, secondarily, P. frederiksbergensis A6 than by the other three isolates. Table1 reports 58.4% and 17.6% inhibition for T14 and A6, respectively; it does not show uniformly strong antagonism by all five members. Co-occurring enzyme or siderophore phenotypes do not identify the inhibition mechanism. P. capsici is an oomycete; chitinase activity does not demonstrate degradation of its wall or a host antifungal defense response.
Participating Taxa: Streptomyces sp., Pseudomonas sp.
Metabolites: siderophore (CHEBI:26672 · MediaIngredientMech · CMMMech)
HYPOTHESIZED - The measured isolate antagonism may contribute to improved host performance under pathogen challenge. The pot study lacked a SynCom-only control and direct disease scoring or pathogen-load measurements, so it cannot isolate pathogen suppression from growth promotion or attribute the host response to these two strains alone.
Evidence
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PMID:40508300 - SUPPORT (IN_VITRO)"The SynCom members exhibited phosphate solubilization, indole-3-acetic acid production, catalase activity, siderophore synthesis, and strong antagonism against P. capsici"
Pepper Growth and Visible Symptoms Under Pathogen Challenge
In the controlled pot experiment, the full five-member SynCom plus pathogen treatment improved root length, height, biomass, stem diameter and chlorophyll compared with the pathogen-only control. The authors also report reduced visible wilting and necrosis. Section3.5 explicitly states that direct disease-severity scoring and pathogen-load measurements were not performed, and that there was no SynCom-only control. Preserve measured growth and visible protection without converting them into quantified pathogen suppression, strain-resolved colonization or an IAA-mediated host mechanism.
Biological Processes:
- plant growth (GO:0040007 · PathwayMech)
Evidence
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PMID:40508300 - SUPPORT (IN_VIVO)"The SynCom reduced disease severity and enhanced the growth of pepper plants."
Knowledge gaps & discussions (1)
KNOWLEDGE_GAP OPEN Which isolate traits and community changes mediate the positive host response?
Individual screens, host growth and visible symptom improvement are distinct. Section3.5 rules out direct disease scoring/pathogen load and a SynCom-only comparison. Community composition and nitrate/K/Ca responses are additional positive findings not yet independently represented as graph nodes; ammonium/nitrite differences are not significant in Results despite stronger Discussion claims. PICRUSt/FUNGuild outputs are predictions, not measured metabolic flux or pathogen load. New structure requires scoped Edison review; no new topology is added here. Source protocol and identity inconsistencies remain a separate metadata issue.
Attaches to: ecological_interactions#Individual-Isolate PGPR Trait Measurements, ecological_interactions#Isolate Antagonism Against Phytophthora capsici, ecological_interactions#Pepper Growth and Visible Symptoms Under Pathogen Challenge
1 evidence item(s)
The SynCom reduced disease severity and enhanced the growth of pepper plants.
The abstract summarizes a positive result; the full paper clarifies that disease protection used visual/physiological proxies rather than direct disease scores or pathogen load.
Environmental Factors
| Factor | Value | Unit |
|---|---|---|
| defined synthetic community design | Bacillus, Flavobacterium, Cytobacillus, Streptomyces, and Pseudomonas isolates from healthy pepper rhizosphere. | N/A |
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Growth Media
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