Abstract
BACKGROUND: Root exudates play a critical role in plant-microorganism interactions. However, information on the metabolic change in root exudates of plants with different disease severities of bacterial wilt is limited. Here, we investigate the differential metabolic pathway and metabolites among root exudates secreted by the low-grade, moderately, and severely Ralstonia solanacearum-infected tobacco plants and healthy plants. RESULTS: Comparative analysis reveals a large divergence among metabolic profiles and rhizosphere microbial communities of the healthy plants and R. solanacearum-infected plants in terms of metabolic spectrum, community composition and diversity. The intensities of efetaal, 6-methylnicotinamide, proline, sinapinic acid, and syringic acid increase with increasing disease severity, which are chemoattractants of R. solanacearum and pathogen helpers Sphingobacterium and Stenotrophomonas, suggesting a potential role of metabolites in pathogen infection. Metabolites upregulated in R. solanacearum-infected plants inhibit the biofilm formation of antagonistic Bacillus amyloliquefaciens WH1. Metabolites elevated in healthy plants including N-acetyl-L-leucine, 3,3-dimethylglutaric acid, 4-ethylphenol, protocatechuic acid, pyridoxine, salicylic acid, trans-cinnamic acid, and tropine are chemoattractants of WH1, support cell growth and enhance biofilm formation and colonization of WH1. McpB and McpC3 are the major methyl-accepting chemotaxis proteins for salicylic acid and trans-cinnamic acid. Nutritional competition is present between WH1 and R. solanacearum. CONCLUSION: Root exudates regulate the rhizosphere microbiome and affect plant resistance. Metabolites upregulated in healthy plants recruit antagonistic bacteria to defend the plant from pathogen invasion. Metabolites upregulated in R. solanacearum-infected plants attract pathogens and their helpers, thus aggravating the disease. © 2025 Society of Chemical Industry.
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Claims 8
Claim · model-written summary
Healthy and infected tobacco plants differed substantially in exudate metabolic profiles and rhizosphere community composition and diversity.
- Taxon
- tobacco
Nicotiana tabacume1 - Interactor
- R. solanacearum
Ralstonia solanacearume0pathogen - Outcome
- metabolic spectrum, community composition and diversitye0
- Comparator
- healthy plants and R. solanacearum-infected plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“large divergence among metabolic profiles and rhizosphere microbial communities of the healthy plants and R. solanacearum-infected plants in terms of metabolic spectrum, community composition and diversity”
e1“tobacco plants”
Claim · model-written summary
Five named exudate metabolites increased as tobacco disease severity increased.
- Taxon
- tobaccoNicotiana tabacume1
- Outcome
- intensities of efetaal, 6-methylnicotinamide, proline, sinapinic acid, and syringic acide0
- Direction
- increasee0
- Comparator
- disease severitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The intensities of efetaal, 6-methylnicotinamide, proline, sinapinic acid, and syringic acid increase with increasing disease severity”
e1“tobacco plants”
Claim · model-written summary
Those five metabolites attracted R. solanacearum and its helper microbes Sphingobacterium and Stenotrophomonas.
- Taxon
- tobaccoNicotiana tabacume1
- Interactor
- R. solanacearumRalstonia solanacearume0pathogen
- Second interactor
- Sphingobacterium and Stenotrophomonas
Sphingobacterium
Stenotrophomonase0other - Outcome
- chemoattractantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“efetaal, 6-methylnicotinamide, proline, sinapinic acid, and syringic acid increase with increasing disease severity, which are chemoattractants of R. solanacearum and pathogen helpers Sphingobacterium and Stenotrophomonas”
e1“tobacco plants”
Claim · model-written summary
Metabolites upregulated in infected tobacco inhibited biofilm formation by antagonistic Bacillus amyloliquefaciens WH1.
- Taxon
- tobaccoNicotiana tabacume1
- Treatment
- Metabolites upregulated in R. solanacearum-infected plantse0
- Interactor
- Bacillus amyloliquefaciens WH1
.jpg?width=60)
Bacillus amyloliquefaciense0biocontrol_agent - Outcome
- biofilm formatione0
- Direction
- inhibite0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“Metabolites upregulated in R. solanacearum-infected plants inhibit the biofilm formation of antagonistic Bacillus amyloliquefaciens WH1”
e1“tobacco plants”
Claim · model-written summary
Metabolites elevated in healthy plants attract WH1 and support its growth, biofilm and colonization.
- Taxon
- tobaccoNicotiana tabacume1
- Interactor
- Bacillus amyloliquefaciens WH1Bacillus amyloliquefaciense2biocontrol_agent
- Outcome
- chemoattractants of WH1, support cell growth and enhance biofilm formation and colonization of WH1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Metabolites elevated in healthy plants including N-acetyl-L-leucine, 3,3-dimethylglutaric acid, 4-ethylphenol, protocatechuic acid, pyridoxine, salicylic acid, trans-cinnamic acid, and tropine are chemoattractants of WH1, support cell growth and enhance biofilm formation and colonization of WH1”
e1“tobacco plants”
e2“Bacillus amyloliquefaciens WH1”
Claim · model-written summary
McpB and McpC3 are major chemotaxis proteins for salicylic acid and trans-cinnamic acid.
- Taxon
- tobaccoNicotiana tabacume1
- Gene
- McpB and McpC3e0
- Compound
- salicylic acid and trans-cinnamic acide0
- Outcome
- methyl-accepting chemotaxis proteinse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“McpB and McpC3 are the major methyl-accepting chemotaxis proteins for salicylic acid and trans-cinnamic acid”
e1“tobacco plants”
Claim · model-written summary
Nutritional competition occurs between WH1 and R. solanacearum.
- Taxon
- tobaccoNicotiana tabacume1
- Interactor
- R. solanacearumRalstonia solanacearume0pathogen
- Second interactor
- Bacillus amyloliquefaciens WH1Bacillus amyloliquefaciense2biocontrol_agent
- Outcome
- Nutritional competitione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nutritional competition is present between WH1 and R. solanacearum”
e1“tobacco plants”
e2“Bacillus amyloliquefaciens WH1”
Claim · model-written summary
The authors conclude that root exudates regulate rhizosphere microbiota and affect plant resistance.
- Taxon
- tobaccoNicotiana tabacume1
- Outcome
- plant resistancee0
- Qualifier
- Root exudates regulate the rhizosphere microbiomee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Root exudates regulate the rhizosphere microbiome and affect plant resistance”
e1“tobacco plants”