Abstract
ABSTRACT Intercropping, as a sustainable agricultural practice, has shown potential to reduce soil-borne diseases through rhizosphere microbial community remodeling. However, whether pepper ( Capsicum annuum L .) confers this benefit to snap bean ( Phaseolus vulgaris L .) remains unclear. This study investigated the disease-suppressive effects of exogenously applied pepper root exudates using pot experiments. In vitro assays were used to validate the biocontrol efficacy of antagonistic bacteria and a key flavonoid metabolite (Chrysin). High-throughput sequencing and untargeted metabolomics were combined to analyze changes in the snap bean rhizosphere microbial community and root exudate profiles under pathogen stress. Compared to the treatment inoculated only with Fusarium solani ( F. solani ) (CKI), the treatment applying root exudates plus F. solani (REI) exhibited a substantial reduction in F. solani abundance, enhanced plant antioxidant enzyme activities, as well as markedly alleviated snap bean root rot symptoms. Furthermore, the REI treatment significantly altered rhizosphere microbial community composition by selectively enriching beneficial microbes (e.g., Actinobacteria, Ascomycota, Streptomyces , Saccharothrix ), enhanced the complexity and stability of the bacterial-fungal cross-domain network, and formed a pathogen antagonism network centered on Streptomyces . Moreover, the REI treatment induced the secretion of flavone compounds (e.g., Chrysin) from snap bean roots, whose relative abundance demonstrated an essential positive correlation with Streptomyces and a significant negative correlation with Fusarium . The findings indicate that exogenous application of pepper root exudates mitigates the incidence of snap bean root rot by restructuring the rhizosphere microbial community and promoting the synthesis of endogenous flavone metabolites in the host plant. This study provides a basis for environmentally friendly vegetable disease management and supports the advancement of sustainable agricultural practices. IMPORTANCE Root rot induced by Fusarium solani poses a serious threat to snap bean production and the sustainable development of agriculture. Long-term continuous cropping intensifies the incidence of soilborne diseases. Conventional chemical control methods are frequently less effective against these diseases and may result in issues, such as the development of pathogen resistance, a decline in soil microbial diversity, and environmental contamination. Despite the fact that intercropping snap beans with peppers can reduce the incidence of snap bean root rot, the precise mechanisms through which pepper root exudates confer this protective effect remain inadequately understood. This study demonstrates that pepper root exudates can effectively reduce the occurrence of snap bean root rot by reshaping the microbial community and inducing the secretion of plant defense metabolites. The significance of this research lies in elucidating the key mechanisms and application potential of pepper root exudates in enhancing snap bean resistance to root rot, thereby providing essential theoretical foundations and practical guidance for the development of novel biological agents and the advancement of green agriculture.
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Claims 10
Claim · model-written summary
Pepper root exudates reduced Fusarium solani abundance in inoculated snap bean compared with pathogen inoculation alone.
- Taxon
- snap beane1
- Treatment
- root exudates plus F. solani (REI)e0
- Interactor
- Fusarium solani
_Sacc._5393379.jpg?width=60)
Fusarium solanie0pathogen - Outcome
- F. solani abundancee0
- Direction
- reductione0
- Comparator
- treatment inoculated only with Fusarium solani ( F. solani ) (CKI)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_Sacc._5393379.jpg?width=500)
Verbatim
e0“Compared to the treatment inoculated only with Fusarium solani ( F. solani ) (CKI), the treatment applying root exudates plus F. solani (REI) exhibited a substantial reduction in F. solani abundance”
e1“pepper ( Capsicum annuum L .) confers this benefit to snap bean ( Phaseolus vulgaris L .)”
Claim · model-written summary
Pepper root exudates enhanced antioxidant enzyme activities in inoculated snap bean.
- Taxon
- snap beane1
- Treatment
- root exudates plus F. solani (REI)e0
- Interactor
- F. solaniFusarium solanie0pathogen
- Outcome
- plant antioxidant enzyme activitiese0
- Direction
- enhancede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the treatment applying root exudates plus F. solani (REI) exhibited a substantial reduction in F. solani abundance, enhanced plant antioxidant enzyme activities”
e1“pepper ( Capsicum annuum L .) confers this benefit to snap bean ( Phaseolus vulgaris L .)”
Claim · model-written summary
Pepper root exudates alleviated snap bean root rot symptoms.
- Taxon
- snap beane0
- Treatment
- root exudates plus F. solani (REI)e1
- Interactor
- Fusarium solaniFusarium solanie2pathogen
- Outcome
- snap bean root rot symptomse0
- Direction
- alleviatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“markedly alleviated snap bean root rot symptoms”
e1“the treatment applying root exudates plus F. solani (REI)”
e2“Fusarium solani ( F. solani )”
Claim · model-written summary
Root exudate treatment significantly altered snap bean rhizosphere microbial community composition.
Not reportedComparatorDirection
Verbatim
e0“the REI treatment significantly altered rhizosphere microbial community composition”
e1“snap bean ( Phaseolus vulgaris L .)”
Claim · model-written summary
Root exudate treatment enriched Actinobacteria, Ascomycota and Streptomyces in the snap bean rhizosphere.
- Taxon
- snap beane2
- Treatment
- REI treatmente1
- Interactor
- ActinobacteriaActinomycetotae0symbiont
- Outcome
- Actinobacteria, Ascomycota, Streptomycese0
- Direction
- enrichinge0
- Qualifier
- Ascomycota, Streptomyces , Saccharothrixe0
Not reportedComparator
Verbatim
e0“selectively enriching beneficial microbes (e.g., Actinobacteria, Ascomycota, Streptomyces , Saccharothrix )”
e1“the REI treatment significantly altered rhizosphere microbial community composition”
e2“snap bean ( Phaseolus vulgaris L .)”
Claim · model-written summary
Root exudate treatment enhanced bacterial-fungal network complexity and stability in the snap bean rhizosphere.
- Taxon
- snap beane2
- Treatment
- REI treatmente1
- Outcome
- complexity and stability of the bacterial-fungal cross-domain networke0
- Direction
- enhancede0
Not reportedComparator
Verbatim
e0“enhanced the complexity and stability of the bacterial-fungal cross-domain network”
e1“the REI treatment significantly altered rhizosphere microbial community composition”
e2“snap bean ( Phaseolus vulgaris L .)”
Claim · model-written summary
Root exudate treatment formed a snap bean rhizosphere pathogen antagonism network centered on Streptomyces.
- Taxon
- snap beane1
- Interactor
- Streptomyces
Streptomycese0biocontrol_agent - Outcome
- pathogen antagonism network centered on Streptomycese0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“formed a pathogen antagonism network centered on Streptomyces”
e1“snap bean ( Phaseolus vulgaris L .)”
Claim · model-written summary
Root exudate treatment induced secretion of Chrysin and other flavones from snap bean roots.
- Taxon
- snap beane0
- Organ / stage
- snap bean rootse0
- Treatment
- REI treatmente0
- Outcome
- secretion of flavone compounds (e.g., Chrysin)e0
- Direction
- inducede0
Not reportedComparator
Verbatim
e0“the REI treatment induced the secretion of flavone compounds (e.g., Chrysin) from snap bean roots”
Claim · model-written summary
Flavone relative abundance correlated positively with Streptomyces in snap bean roots.
- Taxon
- snap beane0
- Organ / stage
- snap bean rootse0
- Interactor
- StreptomycesStreptomycese0biocontrol_agent
- Outcome
- relative abundancee0
- Direction
- positivee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“flavone compounds (e.g., Chrysin) from snap bean roots, whose relative abundance demonstrated an essential positive correlation with Streptomyces”
Claim · model-written summary
Flavone relative abundance correlated negatively with Fusarium in snap bean roots.
FusariumOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“flavone compounds (e.g., Chrysin) from snap bean roots, whose relative abundance demonstrated an essential positive correlation with Streptomyces and a significant negative correlation with Fusarium”
The same questions in other papers
allelopathy · pest · Phaseolus vulgaris (common bean)Positive and negative results
2 in the opposite direction
- no effect
- no effect
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.