Maize Root Simplified Bacterial Community

Community ID CommunityMech:000043

Ecological State ENGINEERED

Environment rhizosphere
ENVO:00005801

A representative 7-member bacterial community from maize rhizosphere, developed through selective iterations to model root-associated microbiome function. The community consists of Enterobacter cloacae AA4, Stenotrophomonas maltophilia AA1, Ochrobactrum pituitosum AA2, Herbaspirillum frisingense, Pseudomonas putida, Curtobacterium pusillum, and Chryseobacterium indologenes. This simplified community reproducibly assembles on root surfaces and provides biocontrol against Fusarium verticillioides, a phytopathogenic fungus. E. cloacae AA4 plays a keystone role, as its removal causes dramatic community composition changes.

Taxonomy

Taxon	Ontology ID	Functional Roles	Abundance
Enterobacter cloacae AA4	NCBITaxon:550	SYNTROPHIC_PARTNER PRIMARY_DEGRADER	DOMINANT
PMID:28275097 - SUPPORT (IN_VITRO) "In this work, from the distinctive microbiota assembled by maize roots, through host-mediated selection, we obtained a greatly simplified synthetic bacterial community consisting of seven strains (Enterobacter cloacae, Stenotrophomonas maltophilia, Ochrobactrum pituitosum, Herbaspirillum frisingense, Pseudomonas putida, Curtobacterium pusillum, and Chryseobacterium indologenes) representing three of the four most dominant phyla found in maize roots" PMID:28275097 - SUPPORT (IN_VIVO) "This result suggests that E. cloacae plays the role of keystone species in this model ecosystem" PMID:28275097 - SUPPORT (IN_VIVO) "In planta and in vitro, this model community inhibited the phytopathogenic fungus Fusarium verticillioides, indicating a clear benefit to the host"
Stenotrophomonas maltophilia AA1	NCBITaxon:40324	SYNTROPHIC_PARTNER	ABUNDANT
PMID:28275097 - SUPPORT (IN_VITRO) "In this work, from the distinctive microbiota assembled by maize roots, through host-mediated selection, we obtained a greatly simplified synthetic bacterial community consisting of seven strains (Enterobacter cloacae, Stenotrophomonas maltophilia, Ochrobactrum pituitosum, Herbaspirillum frisingense, Pseudomonas putida, Curtobacterium pusillum, and Chryseobacterium indologenes) representing three of the four most dominant phyla found in maize roots"
Ochrobactrum pituitosum AA2	NCBITaxon:571256	SYNTROPHIC_PARTNER	ABUNDANT
PMID:28275097 - SUPPORT (IN_VITRO) "In this work, from the distinctive microbiota assembled by maize roots, through host-mediated selection, we obtained a greatly simplified synthetic bacterial community consisting of seven strains (Enterobacter cloacae, Stenotrophomonas maltophilia, Ochrobactrum pituitosum, Herbaspirillum frisingense, Pseudomonas putida, Curtobacterium pusillum, and Chryseobacterium indologenes) representing three of the four most dominant phyla found in maize roots"
Herbaspirillum frisingense	NCBITaxon:92645	SYNTROPHIC_PARTNER	COMMON
Pseudomonas putida	NCBITaxon:303	SYNTROPHIC_PARTNER	COMMON
Curtobacterium pusillum	NCBITaxon:69373	SYNTROPHIC_PARTNER	COMMON
Chryseobacterium indologenes	NCBITaxon:253	SYNTROPHIC_PARTNER	COMMON
Zea mays	NCBITaxon:4577	PRIMARY_PRODUCER	N/A
PMID:28275097 - SUPPORT (IN_VITRO) "In this work, from the distinctive microbiota assembled by maize roots, through host-mediated selection, we obtained a greatly simplified synthetic bacterial community consisting of seven strains (Enterobacter cloacae, Stenotrophomonas maltophilia, Ochrobactrum pituitosum, Herbaspirillum frisingense, Pseudomonas putida, Curtobacterium pusillum, and Chryseobacterium indologenes) representing three of the four most dominant phyla found in maize roots"
Fusarium verticillioides	NCBITaxon:117187		N/A
PMID:28275097 - SUPPORT (IN_VIVO) "In planta and in vitro, this model community inhibited the phytopathogenic fungus Fusarium verticillioides, indicating a clear benefit to the host"

Ecological Interactions

Taxon

Cross-feeding

Mutualism

Syntrophy

Competition

Commensalism

Niche partitioning

Colonization facilitation

Strain competition

Predation

Root Colonization and Community Assembly

MUTUALISM

Source Taxon: Enterobacter cloacae AA4

Target Taxon: Zea mays

Biological Processes:

symbiotic process (GO:0044403)
root colonization (GO:0044010)

Evidence

PMID:28275097 - SUPPORT (IN_VITRO)

"In this work, from the distinctive microbiota assembled by maize roots, through host-mediated selection, we obtained a greatly simplified synthetic bacterial community consisting of seven strains (Enterobacter cloacae, Stenotrophomonas maltophilia, Ochrobactrum pituitosum, Herbaspirillum frisingense, Pseudomonas putida, Curtobacterium pusillum, and Chryseobacterium indologenes) representing three of the four most dominant phyla found in maize roots"

Host Protection from Fusarium verticillioides Disease

MUTUALISM

Source Taxon: Enterobacter cloacae AA4

Target Taxon: Zea mays

Biological Processes:

defense response to fungus (GO:0050832)

Evidence

PMID:28275097 - SUPPORT (IN_VITRO)

"In planta and in vitro, this model community inhibited the phytopathogenic fungus Fusarium verticillioides, indicating a clear benefit to the host"

Root Microbiome Assembly

MUTUALISM

Source Taxon: Stenotrophomonas maltophilia AA1

Target Taxon: Zea mays

Biological Processes:

plant-bacterium mutualism (GO:0044403)

Evidence

PMID:28275097 - SUPPORT (IN_VITRO)

"In this work, from the distinctive microbiota assembled by maize roots, through host-mediated selection, we obtained a greatly simplified synthetic bacterial community consisting of seven strains (Enterobacter cloacae, Stenotrophomonas maltophilia, Ochrobactrum pituitosum, Herbaspirillum frisingense, Pseudomonas putida, Curtobacterium pusillum, and Chryseobacterium indologenes) representing three of the four most dominant phyla found in maize roots"

Rhizosphere Nutrient Cycling

MUTUALISM

Source Taxon: Ochrobactrum pituitosum AA2

Target Taxon: Zea mays

Biological Processes:

plant-bacterium mutualism (GO:0044403)

Evidence

PMID:28275097 - SUPPORT (IN_VITRO)

"In this work, from the distinctive microbiota assembled by maize roots, through host-mediated selection, we obtained a greatly simplified synthetic bacterial community consisting of seven strains (Enterobacter cloacae, Stenotrophomonas maltophilia, Ochrobactrum pituitosum, Herbaspirillum frisingense, Pseudomonas putida, Curtobacterium pusillum, and Chryseobacterium indologenes) representing three of the four most dominant phyla found in maize roots"

Plant Growth Promotion

MUTUALISM

Source Taxon: Herbaspirillum frisingense

Target Taxon: Zea mays

Biological Processes:

plant-bacterium mutualism (GO:0044403)

Evidence

PMID:28275097 - SUPPORT (IN_VITRO)

"In this work, from the distinctive microbiota assembled by maize roots, through host-mediated selection, we obtained a greatly simplified synthetic bacterial community consisting of seven strains (Enterobacter cloacae, Stenotrophomonas maltophilia, Ochrobactrum pituitosum, Herbaspirillum frisingense, Pseudomonas putida, Curtobacterium pusillum, and Chryseobacterium indologenes) representing three of the four most dominant phyla found in maize roots"

Root Surface Colonization

MUTUALISM

Source Taxon: Pseudomonas putida

Target Taxon: Zea mays

Biological Processes:

plant-bacterium mutualism (GO:0044403)

Evidence

PMID:28275097 - SUPPORT (IN_VITRO)

"In this work, from the distinctive microbiota assembled by maize roots, through host-mediated selection, we obtained a greatly simplified synthetic bacterial community consisting of seven strains (Enterobacter cloacae, Stenotrophomonas maltophilia, Ochrobactrum pituitosum, Herbaspirillum frisingense, Pseudomonas putida, Curtobacterium pusillum, and Chryseobacterium indologenes) representing three of the four most dominant phyla found in maize roots"

Biofilm Formation and Root Association

MUTUALISM

Source Taxon: Curtobacterium pusillum

Target Taxon: Zea mays

Biological Processes:

plant-bacterium mutualism (GO:0044403)

Evidence

PMID:28275097 - SUPPORT (IN_VITRO)

"In this work, from the distinctive microbiota assembled by maize roots, through host-mediated selection, we obtained a greatly simplified synthetic bacterial community consisting of seven strains (Enterobacter cloacae, Stenotrophomonas maltophilia, Ochrobactrum pituitosum, Herbaspirillum frisingense, Pseudomonas putida, Curtobacterium pusillum, and Chryseobacterium indologenes) representing three of the four most dominant phyla found in maize roots"

Organic Matter Metabolism

MUTUALISM

Source Taxon: Chryseobacterium indologenes

Target Taxon: Zea mays

Biological Processes:

plant-bacterium mutualism (GO:0044403)

Evidence

PMID:28275097 - SUPPORT (IN_VITRO)

"In this work, from the distinctive microbiota assembled by maize roots, through host-mediated selection, we obtained a greatly simplified synthetic bacterial community consisting of seven strains (Enterobacter cloacae, Stenotrophomonas maltophilia, Ochrobactrum pituitosum, Herbaspirillum frisingense, Pseudomonas putida, Curtobacterium pusillum, and Chryseobacterium indologenes) representing three of the four most dominant phyla found in maize roots"

Antifungal Biocontrol of Fusarium verticillioides

COMPETITION

Source Taxon: Enterobacter cloacae AA4

Target Taxon: Fusarium verticillioides

Biological Processes:

defense response to fungus (GO:0050832)

Evidence

PMID:28275097 - SUPPORT (IN_VIVO)

"In planta and in vitro, this model community inhibited the phytopathogenic fungus Fusarium verticillioides, indicating a clear benefit to the host"

Keystone Stabilization Against Curtobacterium pusillum Takeover

COMPETITION

Source Taxon: Enterobacter cloacae AA4

Target Taxon: Curtobacterium pusillum

Evidence

PMID:28275097 - SUPPORT (IN_VIVO)

"Only the removal of E. cloacae led to the complete loss of the community, and C. pusillum took over"
PMID:28275097 - SUPPORT (IN_VIVO)

"This result suggests that E. cloacae plays the role of keystone species in this model ecosystem"

Community-Level Biocontrol and Keystone Maintenance

COLONIZATION_FACILITATION

Biological Processes:

defense response to fungus (GO:0050832)
symbiotic process (GO:0044403)

Evidence

PMID:28275097 - SUPPORT (IN_VIVO)

"In planta and in vitro, this model community inhibited the phytopathogenic fungus Fusarium verticillioides, indicating a clear benefit to the host"
PMID:28275097 - SUPPORT (IN_VIVO)

"This result suggests that E. cloacae plays the role of keystone species in this model ecosystem"

Environmental Factors

Factor	Value	Unit
Target pathogen	Fusarium verticillioides	N/A
Keystone species	Enterobacter cloacae AA4	N/A
Assembly dynamics	reproducible colonization	N/A
Agricultural application	biocontrol for bioenergy crops	N/A

Growth Media

1/2 Murashige and Skoog (MS) agar gnotobiotic maize-root system (members precultured on 0.1x TSA / tryptic soy broth)

pH 6.0

Temperature 30 °C

Preparation notes: Community members were streaked on 0.1x TSA plates (30 °C, 24-48 h) and precultured in tryptic soy broth (TSB) shaken at 30 °C before inoculation. The simplified synthetic community was assembled on the roots of axenic maize seedlings grown in sterile 1/2 MS agar [0.8% (wt/vol), pH adjusted to 6.0 to simulate soil pH] within double-tube gnotobiotic chambers. Surface-sterilized seeds were germinated at 30 °C in the dark for ~50-55 h. Soil-grown plants were kept in a plant growth chamber at 25 °C with 54% relative humidity under a 16 h light / 8 h dark cycle.

Evidence

PMID:28275097

"The bacterial strains for inoculation were streaked on 0.1× TSA plates and incubated at 30 °C for 24–48 h. Then, a single colony of each strain was inoculated in 5 mL of tryptic soy broth (TSB) and shaken at 30 °C overnight."

PMID:28275097

"the resulting seedlings were grown in sterile 1/2 Murashige and Skoog (MS) agar [0.8% (wt/vol)] (adjusting the pH to 6.0 to simulate the pH of soil"

PMID:28275097

"A seed inoculated with bacteria was put into a glass test tube (16 × 150 mm) containing 20 mL of 1/2 MS agar"

PMID:28275097

"10 seeds, embryo side up, were placed in a Perti dish (9-cm diameter) filled with 7 mL of sterile water and incubated at 30 °C in the dark until the seeds germinated (usually after 50–55 h)."

PMID:28275097

"the pots were placed in a plant growth chamber under the following conditions: 16 h of light (day) and 8 h of dark (night), 25 °C, and a relative humidity of 54%."