A rhizobacteria synthetic community (SynCom) named MetG2 inoculated onto sugarcane in a greenhouse experiment to enhance stress resilience through targeted modulation of plant-microbe interactions. Shotgun metagenome and metatranscriptome sequencing revealed temporal shifts in the rhizosphere microbial community, with up-regulation of genes for flagellar assembly, chemotaxis, quorum sensing, and biofilm formation (particularly within Proteobacteria), indicating active microbial movement toward root surfaces, alongside enrichment of genes for nutrient acquisition, hormone synthesis, siderophore production, and VOC synthesis. Sugarcane responded with up-regulation of hormone-related and nutrient-transporter genes and induction of stress-resistance genes, supporting MetG2 as a sustainable strategy to enhance crop productivity and resilience.
Taxonomy
| Taxon | Ontology ID | Functional Roles | Abundance |
|---|---|---|---|
| sugarcane (Saccharum; species unresolved) — ontology label: Saccharum | NCBITaxon:4546 · TaxonMech · TraitMech |
PRIMARY_PRODUCER
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N/A |
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| Proteobacteria (rhizosphere community members) — ontology label: Pseudomonadota | NCBITaxon:1224 · 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.
Rhizosphere colonization-associated gene expression
After MetG2 inoculation, the rhizosphere showed increased expression of flagellar assembly, chemotaxis, quorum-sensing and biofilm-associated genes, particularly within Proteobacteria. The authors interpret this as movement toward roots; the reviewed evidence is molecular, not direct tracking of cells or proof that one organism facilitates another's colonization. Responding native rhizosphere taxa must not be equated with the defined MetG2 inoculant.
Participating Taxa: Proteobacteria (rhizosphere community members)
Biological Processes:
- bacterial-type flagellum assembly (GO:0044780 · PathwayMech)
- chemotaxis (GO:0006935 · PathwayMech)
- quorum sensing (GO:0009372 · PathwayMech)
- biofilm formation (GO:0042710 · PathwayMech)
Evidence
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doi:10.1016/j.rhisph.2025.101142 - PARTIAL (IN_VIVO)"an up-regulation of genes related to flagellar assembly, chemotaxis, quorum sensing, and biofilm formation, particularly within Proteobacteria, indicating active microbial movement toward root surfaces"
Rhizosphere enrichment of plant-associated functional genes
Rhizosphere genes associated with nutrient acquisition, hormone synthesis, siderophore production and VOC synthesis were enriched after MetG2 inoculation. The source interprets these changes as potentially beneficial microbial activities. Gene enrichment is not direct measurement of secreted products, transfer to the host or reciprocal fitness, and is not assigned exclusively to the inoculated strains or to one responding phylum.
Biological Processes:
- biological process involved in interspecies interaction between organisms (GO:0044419 · PathwayMech)
HYPOTHESIZED/PARTIAL: the enriched microbial functions are proposed to contribute to the host transcriptional response in the MetG2-associated plant-microbe system. The reviewed omics evidence does not identify a transferred causal signal, establish that gene enrichment precedes the host response, or isolate mediation by the inoculant from the native rhizosphere community.
Evidence
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doi:10.1016/j.rhisph.2025.101142 - SUPPORT (IN_VIVO)"genes associated with nutrient acquisition, hormone synthesis, siderophore production, and volatile organic compound (VOC) synthesis were enriched, suggesting stimulated beneficial microbial activities"
Sugarcane hormone and nutrient-transporter response
Sugarcane showed increased expression of hormone-related and nutrient-transporter genes after MetG2 inoculation, together with stress-response transcription. These are positive molecular responses, not by themselves a quantified stress-tolerance phenotype or reciprocal microbial benefit. The named participant is the study host at a parent-only Saccharum anchor; species and cultivar remain unverified. This is not transcription by the bacterial inoculant or a response demonstrated across the genus.
Participating Taxa: sugarcane (Saccharum; species unresolved)
Biological Processes:
- biological process involved in interspecies interaction between organisms (GO:0044419 · PathwayMech)
Evidence
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doi:10.1016/j.rhisph.2025.101142 - SUPPORT (IN_VIVO)"Sugarcane plants also exhibited dynamic responses, including the up-regulation of hormone-related genes (auxin, cytokinin, salicylic acid) and nutrient transporter genes"
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doi:10.1016/j.rhisph.2025.101142 - SUPPORT (IN_VIVO)"Stress resistance genes such as trehalose 6-phosphate phosphatase, phenylalanine ammonia-lyase, expansin, and antioxidant-related genes were also induced."
Knowledge gaps & discussions (1)
KNOWLEDGE_GAP OPEN Which MetG2 members and host identity underlie the observed native-rhizosphere and sugarcane transcriptional responses?
The indexed publisher Introduction and experimental-design preview name four MetG2 strains, unlike the record's broad responding-phylum wrapper. The previews disagree between Chiliseed2 and Chileseed2; their equivalence remains unverified. These are membership leads, not newly accepted strain identities. The unsupported species-level sugarcane grounding has been replaced by an explicit Saccharum parent-rank anchor, but the experimental host species/cultivar and inoculant roster still require source verification under issue1847; the record remains needs_research. The host-response participant now names only the plant, and the colonization-expression participant names the documented responding phylum, not the host or the defined inoculant. Preserve the proposed functional contribution without treating co-occurring expression, gene enrichment and host response as a demonstrated causal sequence.
Attaches to: ecological_interactions#Rhizosphere colonization-associated gene expression, ecological_interactions#Rhizosphere enrichment of plant-associated functional genes, ecological_interactions#Sugarcane hormone and nutrient-transporter response
2 evidence item(s)
genes associated with nutrient acquisition, hormone synthesis, siderophore production, and volatile organic compound (VOC) synthesis were enriched, suggesting stimulated beneficial microbial activities
Supports functional gene enrichment and its proposed beneficial interpretation, not demonstrated mutualism or metabolite transfer.
Sugarcane plants also exhibited dynamic responses, including the up-regulation of hormone-related genes (auxin, cytokinin, salicylic acid) and nutrient transporter genes
Supports the sugarcane hormone and nutrient-transporter gene response after MetG2 inoculation.
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