Abstract
Rice (Oryza sativa) is a major crop in much of the developing world where disease management using pesticides is not economically practical nor environmentally safe. The identification of biocontrol agents therefore presents a useful alternative. Here, we have screened bacterial strains isolated from the rhizosphere of rice plants, and identified a number of these that exhibit antagonistic activity towards the fungal pathogen, Rhizoctonia solani, the causative agent of rice sheath blight disease. Antagonism was strongly correlated with the quantity of siderophores produced by individual strains, and was increased under iron-limiting conditions. Selected high-siderophore-producing strains Bacillus subtilis SPS2, Bacillus cereus Z2-7, Enterobacter sp. SPR7 and Aeromonas hydrophilla BPS10 were found to promote the growth of rice plants, possibly via the solubilisation of soil phosphates, nitrogen fixation and the production of phytohormones. These same plant growth promoting rhizobacteria (PGPR) also conferred resistance against sheath blight disease, which resulted in significant yield increases in infected plants. A consortium of these selected strains was especially effective in both growth promotion and disease suppression, and generally performed better than treatment with the fungicide, benlate. Molecular analysis indicated that the PGPR strains tested enhanced expression of chitinases, peroxidases and glucanases in rice, and may therefore activate induced systemic resistance in this plant species. Our work has identified a series of rhizobacterial strains able to promote growth and provide effective resistance against sheath blight disease in rice and which therefore have potential for application as biocontrol agents in agriculture.
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Claims 13
Claim · model-written summary
Several rice rhizosphere strains antagonized Rhizoctonia solani.
- Taxon
- Rice
Oryza sativae1 - Interactor
- Rhizoctonia solani
Rhizoctonia solanie0pathogen - Outcome
- antagonistic activity towards the fungal pathogen, Rhizoctonia solanie0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“identified a number of these that exhibit antagonistic activity towards the fungal pathogen, Rhizoctonia solani”
e1“Rice (Oryza sativa)”
Claim · model-written summary
Antagonism correlated strongly with siderophore quantity.
- Taxon
- riceOryza sativae1
- Compound
- siderophorese0
- Outcome
- Antagonisme0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Antagonism was strongly correlated with the quantity of siderophores produced by individual strains”
e1“rhizosphere of rice plants”
Claim · model-written summary
Iron limitation increased antagonism.
- Taxon
- riceOryza sativae1
- Treatment
- iron-limiting conditionse0
- Outcome
- Antagonisme0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Antagonism was strongly correlated with the quantity of siderophores produced by individual strains, and was increased under iron-limiting conditions”
e1“rhizosphere of rice plants”
Claim · model-written summary
Bacillus subtilis SPS2 promoted rice growth.
- Taxon
- riceOryza sativae0
- Treatment
- Bacillus subtilis SPS2e0
- Interactor
- Bacillus subtilis SPS2
Bacillus subtilise0biocontrol_agent - Outcome
- growth of rice plantse0
- Direction
- promotee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Bacillus subtilis SPS2, Bacillus cereus Z2-7, Enterobacter sp. SPR7 and Aeromonas hydrophilla BPS10 were found to promote the growth of rice plants”
Claim · model-written summary
Bacillus cereus Z2-7 promoted rice growth.
- Taxon
- riceOryza sativae0
- Treatment
- Bacillus cereus Z2-7e0
- Interactor
- Bacillus cereus Z2-7
Bacillus cereuse0biocontrol_agent - Outcome
- growth of rice plantse0
- Direction
- promotee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Bacillus subtilis SPS2, Bacillus cereus Z2-7, Enterobacter sp. SPR7 and Aeromonas hydrophilla BPS10 were found to promote the growth of rice plants”
Claim · model-written summary
Enterobacter sp. SPR7 promoted rice growth.
- Taxon
- riceOryza sativae0
- Treatment
- Enterobacter sp. SPR7e0
- Interactor
- Enterobacter sp. SPR7
Enterobacter sp. SPR7e0biocontrol_agent - Outcome
- growth of rice plantse0
- Direction
- promotee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Bacillus subtilis SPS2, Bacillus cereus Z2-7, Enterobacter sp. SPR7 and Aeromonas hydrophilla BPS10 were found to promote the growth of rice plants”
Claim · model-written summary
Aeromonas hydrophilla BPS10 promoted rice growth.
- Taxon
- riceOryza sativae0
- Treatment
- Aeromonas hydrophilla BPS10e0
- Interactor
- Aeromonas hydrophilla BPS10e0biocontrol_agent
- Outcome
- growth of rice plantse0
- Direction
- promotee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Bacillus subtilis SPS2, Bacillus cereus Z2-7, Enterobacter sp. SPR7 and Aeromonas hydrophilla BPS10 were found to promote the growth of rice plants”
Claim · model-written summary
These rhizobacteria conferred resistance to sheath blight.
- Taxon
- riceOryza sativae1
- Treatment
- plant growth promoting rhizobacteria (PGPR)e0
- Interactor
- rhizobacteriaHyphomicrobialese0biocontrol_agent
- Outcome
- resistance against sheath blight diseasee0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“These same plant growth promoting rhizobacteria (PGPR) also conferred resistance against sheath blight disease”
e1“growth of rice plants”
Claim · model-written summary
Resistance induced by PGPR significantly increased yield in infected rice.
- Taxon
- riceOryza sativae1
- Treatment
- plant growth promoting rhizobacteria (PGPR)e0
- Interactor
- rhizobacteriaHyphomicrobialese0biocontrol_agent
- Outcome
- yielde0
- Direction
- increasese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“These same plant growth promoting rhizobacteria (PGPR) also conferred resistance against sheath blight disease, which resulted in significant yield increases in infected plants”
e1“growth of rice plants”
Claim · model-written summary
The selected-strain consortium was especially effective for growth promotion.
- Taxon
- riceOryza sativae1
- Treatment
- consortium of these selected strainse0
- Outcome
- growth promotione0
- Direction
- bettere0
- Comparator
- treatment with the fungicide, benlatee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A consortium of these selected strains was especially effective in both growth promotion and disease suppression, and generally performed better than treatment with the fungicide, benlate”
e1“growth of rice plants”
Claim · model-written summary
The selected-strain consortium was especially effective for disease suppression and generally better than benlate.
- Taxon
- riceOryza sativae1
- Treatment
- consortium of these selected strainse0
- Outcome
- disease suppressione0
- Direction
- bettere0
- Comparator
- treatment with the fungicide, benlatee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A consortium of these selected strains was especially effective in both growth promotion and disease suppression, and generally performed better than treatment with the fungicide, benlate”
e1“growth of rice plants”
Claim · model-written summary
PGPR enhanced chitinase, peroxidase and glucanase expression in rice.
- Taxon
- riceOryza sativae0
- Treatment
- PGPR strainse0
- Gene
- chitinases, peroxidases and glucanasese0
- Outcome
- expression of chitinases, peroxidases and glucanasese0
- Direction
- enhancede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“PGPR strains tested enhanced expression of chitinases, peroxidases and glucanases in rice”
Claim · model-written summary
The authors suggest PGPR may activate induced systemic resistance.
- Taxon
- riceOryza sativae1
- Outcome
- induced systemic resistancee0
- Qualifier
- may therefore activatee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“may therefore activate induced systemic resistance in this plant species”
e1“PGPR strains tested enhanced expression of chitinases, peroxidases and glucanases in rice”
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See all 8 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.