A two-member Bacillus subtilis/Serratia marcescens synthetic microbial consortium, BS, pairing the antagonistic strains XY-6 and XB-7, isolated from root-rot-affected Panax notoginseng plantation soil, for Fusarium root-rot biocontrol. Deng et al. 2026 selected Bacillus subtilis XY-6 as the core strain after antagonistic screening, combined compatible strains with XY-6 in 1:1 volume ratios, and found that the XY-6/XB-7 consortium improved greenhouse disease suppression beyond the single strains, directly inhibited Fusarium solani LP2 through cell-free filtrates, activated host antioxidant defenses, and reshaped the P. notoginseng rhizosphere mycobiome.
Taxonomy
| Taxon | Ontology ID | Functional Roles | Abundance |
|---|---|---|---|
| Bacillus subtilis XY-6 — ontology label: Bacillus subtilis | NCBITaxon:1423 · TaxonMech · TraitMech |
PATHOGEN_ANTAGONIST
|
DOMINANT |
|
|||
| Serratia marcescens XB-7 — ontology label: Serratia marcescens | NCBITaxon:615 · TaxonMech · TraitMech |
PATHOGEN_ANTAGONIST
|
DOMINANT |
|
|||
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.
XY-6/XB-7 Fusarium Root-Rot Suppression
The equal-volume Bacillus subtilis XY-6/Serratia marcescens XB-7 consortium reduced root rot by 56% in the initial continuous-cropping greenhouse screen, compared with 21-25% for individual strains. A separate LP2-challenged soil follow-up reported 61% reduction and increased root biomass. These positive treatment effects are distinct assays, not a universal suppression rate, demonstrated -/- resource competition, formal synergy test or field-efficacy result.
Biological Processes:
- defense response (GO:0006952 · PathwayMech)
Evidence
-
PMID:41872736 - SUPPORT (IN_VIVO)"BS application significantly enhanced disease suppression (56%) compared with single-strain treatments"
BS Cell-Free Filtrate Antagonism
Cell-free filtrates from separately grown XY-6 and XB-7 cultures were mixed 1:1, not collected from a coculture. They inhibited Fusarium solani LP2 growth more than individual filtrates, with reported inhibition of 24%, 30% and 38% at 2.5%, 40% and undiluted applications. The first two were mixed into PDA, whereas undiluted filtrate was surface-spread. Direct inhibition is supported; chemical identity, formal additivity/synergy, induced cooperative biosynthesis and mediation of greenhouse disease reduction were not isolated.
Biological Processes:
- biological process involved in interspecies interaction between organisms (GO:0044419 · PathwayMech)
Evidence
-
PMID:41872736 - SUPPORT (IN_VITRO)"prepared by mixing sterile filtrates from individual bacterial strains at a 1:1 ratio."
-
PMID:41872736 - SUPPORT (IN_VITRO)"achieving inhibition rates of 24%, 30%, and 38%"
BS Root Antioxidant and Oxidative-Damage Response
BS treatment lowered root MDA by 38% in LP2-inoculated sterilized soil and 34% in continuous-cropping soil. Results report POD increases of 133% and 173%, and SOD increases of 155% and 62%, respectively; these assignments differ from the abstract summary. Root biomarkers support an antioxidant response and reduced oxidative damage. Systemic resistance and its causal mediation of disease suppression remain author interpretations, not demonstrated by distal-tissue or pathway-blocking experiments in the inspected main text.
Biological Processes:
- defense response (GO:0006952 · PathwayMech)
Evidence
-
PMID:41872736 - SUPPORT (IN_VIVO)"by 38% and 34% in sterilized soil inoculated with F. solani and in continuous-cropping soils, respectively."
-
PMID:41872736 - SUPPORT (IN_VIVO)"activity increasing by 133% and 173%"
-
PMID:41872736 - SUPPORT (IN_VIVO)"activity increasing by 155% and 62%"
BS Rhizosphere Fungal-Community Remodeling
Endpoint ITS profiling after BS treatment showed increased fungal richness, Mortierellomycota relative enrichment and reduced Ascomycota. Fungal co-occurrence networks had more nodes, edges and higher average degree than single-strain networks. These are treatment-associated compositional and correlation-network outcomes, not measured absolute growth of beneficial fungi, strain-resolved inoculant colonization, direct fungal cooperation, causal mediation of disease suppression or experimentally challenged ecological resilience.
Evidence
-
PMID:41872736 - SUPPORT (IN_VIVO)"The microbial community structure in the rhizosphere underwent substantial modifications following inoculation"
-
PMID:41872736 - SUPPORT (IN_VIVO)"Analysis of co-occurrence networks demonstrated that the BS consortium specifically improved the structural robustness and interconnectedness of fungal community networks"
Associated Datasets
| Dataset | Type | Repository | Accession |
|---|---|---|---|
|
Panax notoginseng rhizosphere soil microbiome BioProject
BioProject for raw rhizosphere soil microbiome sequencing data from the Panax notoginseng Fusarium root-rot SynCom study. |
OTHER | NCBI_BIOPROJECT | PRJNA1379223 |
Knowledge gaps & discussions (2)
KNOWLEDGE_GAP OPEN Which strain-resolved colonization dynamics and non-volatile antifungal metabolites connect Bacillus subtilis XY-6 and Serratia marcescens XB-7 to long-term Fusarium suppression in the P. notoginseng rhizosphere?
Deng et al. 2026 reported stronger BS filtrate inhibition and genus-level Bacillus/Serratia enrichment in rhizosphere amplicon data, but the article did not resolve individual antifungal metabolites or directly track the introduced strains apart from their genera.
Attaches to: ecological_interactions#BS Rhizosphere Fungal-Community Remodeling, ecological_interactions#BS Cell-Free Filtrate Antagonism
KNOWLEDGE_GAP OPEN Which of mixed-filtrate inhibition, root antioxidant responses and fungal community changes causally mediate BS disease protection?
Four positive assay outcomes remain, with no new arrows joining separate experiments or converting co-occurrence to causation. Initial and follow-up disease assays, separately prepared filtrates, root biomarkers and endpoint amplicons do not isolate the proposed three mediators. No metabolite identity, systemic pathway requirement, formal synergistic interaction or network resilience should be inferred from these measurements alone.
Attaches to: ecological_interactions#XY-6/XB-7 Fusarium Root-Rot Suppression, ecological_interactions#BS Cell-Free Filtrate Antagonism, ecological_interactions#BS Root Antioxidant and Oxidative-Damage Response, ecological_interactions#BS Rhizosphere Fungal-Community Remodeling
1 evidence item(s)
prepared by mixing sterile filtrates from individual bacterial strains at a 1:1 ratio.
Methods distinguish mixed monoculture filtrates from coculture secretions.
External Resources
| Name | Repository | Resource ID |
|---|---|---|
|
Primary publication - Panax Bacillus-Serratia root-rot biocontrol SynCom
BMC Plant Biology 2026 open-access primary article, doi:10.1186/s12870-026-08617-4, describing the two-member Bacillus subtilis/Serratia marcescens BS SynCom for P. notoginseng root-rot biocontrol. |
OTHER | PMID:41872736 |
|
||
Environmental Factors
| Factor | Value | Unit |
|---|---|---|
| equal-volume BS assembly | Bacillus subtilis XY-6 + Serratia marcescens XB-7 | 1:1 v/v bacterial suspension |
|
||
Cross-Mech Suite Links
Explore related entities across the CultureBotAI X-Mech knowledge bases: