Jala Maize PGPB SynCom

The mixed SynCom 3 inoculant produced positive phosphate-solubilization, indole-reactive colorimetric, ACC-growth, metal-chelation and acetylene-reduction assay results. Salkowski chemistry is not specific identification of IAA; growth with ACC as sole nitrogen source is an indirect deaminase screen. Acetylene reduction is a nitrogenase proxy, not measured nitrogen transfer to maize, and the CAS assay does not identify a particular metallophore. These positive in-vitro traits were not selectively perturbed as mediators of plant growth. The four canonical participants are a subset of the reported six-strain SynCom 3, not a complete four-member inoculant; exact membership and the primary Pseudomonas strain inconsistency remain under #1521.

Participating Taxa: Pseudomonas protegens, Pantoea ananatis, Klebsiella variicola, Burkholderia sp.

Metabolites: phosphate ion (CHEBI:35780 · MediaIngredientMech · CMMMech), indole-3-acetic acid (CHEBI:16411 · MediaIngredientMech · CMMMech), 1-aminocyclopropanecarboxylic acid (CHEBI:18053 · MediaIngredientMech · CMMMech)

Biological Processes:

• nitrogen fixation (GO:0009399 · PathwayMech)

Evidence

• PMID:37275168 - SUPPORT (IN_VITRO)
  "Phosphate solubilization, IAA, BNF, metallophores, biocontrol against Fusarium oxysporum, Pestalotia sp., Curvularia sp."
• PMID:37275168 - SUPPORT (IN_VITRO)
  "SynCom 3 accumulated more soluble orthophosphate"
• PMID:37275168 - SUPPORT (IN_VITRO)
  "Aminocyclopropane-1-carboxylate (ACC) deaminase production"
• PMID:37275168 - SUPPORT (IN_VITRO)
  "only SynCom 3 exhibited evident growth in the BMGM media and reduced acetylene"

SynCom 3 inhibited several tested fungi in vitro, reaching up to 80 percent in the reported comparisons, but Helminthosporium was hardly inhibited by SynCom 3. It also tripled maize-root phenylalanine ammonia-lyase activity. These are positive but distinct assays: the authors did not test induced systemic resistance with a fungal challenge. PAL induction and inhibition of these cultured fungi do not by themselves demonstrate the mechanism of rust reduction in the field. The four canonical participants are a subset of the reported six-strain SynCom 3, not a complete four-member inoculant; exact membership and the primary Pseudomonas strain inconsistency remain under #1521.

Participating Taxa: Pseudomonas protegens, Pantoea ananatis, Klebsiella variicola, Burkholderia sp.

Biological Processes:

• biological process involved in interspecies interaction between organisms (GO:0044419 · PathwayMech)

Evidence

• PMID:37275168 - SUPPORT (IN_VITRO)
  "SynCom 3 exhibited the highest inhibition percentages reaching 80% of inhibition"
• PMID:37275168 - SUPPORT (IN_VIVO)
  "only the effect of SynCom 3 was statistically significant as it tripled the activity of the enzyme"

SynCom 3 inoculation increased Conejo maize growth in gnotobiotic tubes and greenhouse pots. Gnotobiotic root and shoot sizes were 4.2 and 3.0 times the controls. In greenhouse comparisons, root/shoot lengths were 3.3/1.4 times controls and shoot/root dry weights were 2.3/3 times controls. These are positive whole-inoculant treatment effects in the Conejo landrace, not proof that its earlier in-vitro trait panel caused them or that those seedlings produced the separate hybrid field harvest. The four canonical participants are a subset of the reported six-strain SynCom 3, not a complete four-member inoculant; exact membership and the primary Pseudomonas strain inconsistency remain under #1521.

Participating Taxa: Pseudomonas protegens, Pantoea ananatis, Klebsiella variicola, Burkholderia sp.

Biological Processes:

• growth (GO:0040007 · PathwayMech)

Evidence

• PMID:37275168 - SUPPORT (IN_VIVO)
  "promoted the growth of the roots and shoots to sizes 4.2 and 3.0 times greater"
• PMID:37275168 - SUPPORT (IN_VIVO)
  "increases of 3.3 and 1.4 times the roots and shoot length and 2.3 and 3 times the dry weights"

In the reported one-site field experiment with CPL9105W hybrid maize, SynCom 3 treatment increased grain yield from 11 to 16 tons/ha relative to control. The abstract reports rust incidence falling from 12.5 to 8 percent, not a 12.5-percentage-point reduction. The treatment involved seed inoculation and subsequent applications; it is distinct from the Conejo seedling experiments. The whole-inoculant effects do not establish which traits or members mediated them, universal efficacy across sites/seasons, or a benefit for every tested SynCom. The four canonical participants are a subset of the reported six-strain SynCom 3, not a complete four-member inoculant; exact membership and the primary Pseudomonas strain inconsistency remain under #1521.

Participating Taxa: Pseudomonas protegens, Pantoea ananatis, Klebsiella variicola, Burkholderia sp.

Biological Processes:

• growth (GO:0040007 · PathwayMech)
• biological process involved in interspecies interaction between organisms (GO:0044419 · PathwayMech)

Evidence

• PMID:37275168 - SUPPORT (IN_VIVO)
  "the yield increased from 11 tons/ha for the control to 16 tons/ha inoculated with SynCom 3"
• PMID:37275168 - SUPPORT (IN_VIVO)
  "incidence of rust fungal infections decreased significantly from 12.5% in the control to 8% in the treatment with SynCom 3"