Abstract
Phage therapy has garnered significant attention due to the rise of life-threatening multidrug-resistant pathogenic bacteria and the growing awareness of the transfer of resistance genes between pathogens. Considering this, phage therapy applications are being extended to target plant pathogenic bacteria, such as Erwinia amylovora, which causes fire blight in apple and pear orchards. Understanding the mechanisms involved in phage resistance is crucial for enhancing the effectiveness of phage therapy. Despite the challenges of naturally developing a bacteriophage-insensitive mutant (BIM) of E. amylovora (without traditional mutagenesis methods), this study successfully created a BIM against the podovirus ϕEa46-1-A1. The parent strain, E. amylovora D7, and the BIM B6-2 were extensively compared at genomic, transcriptomic, and phenotypic levels. The phenotypic comparison included the metabolic behavior, biofilm formation, and in planta evaluations of pathogenicity. The results revealed a mutation in strain B6-2 in the rcsB gene, which encodes a second regulator in the Rcs two-component phosphorelay system (TCS). This mutation resulted in significant changes in the B6-2 BIM, including downregulation of amylovoran gene expression (e.g., an average log2 fold change of −4.35 across amsA-L), visible alterations in biofilm formation, increased sensitivity to antibiotics (22.4% more sensitive to streptomycin), and a loss of pathogenicity as assessed in an apple seedling virulence model in comparison to the wildtype strain. The findings presented in this study highlight the critical role of the Rcs phosphorelay system in phage resistance in E. amylovora. Based on these findings, we have proposed a model that explains the effect of the B6-2 rcsB mutation on the Rcs phosphorelay system and its contribution to the development of phage resistance in E. amylovora.
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Claims 7
Claim · model-written summary
A bacteriophage-insensitive mutant of E. amylovora was created against phage ϕEa46-1-A1.
- Taxon
- apple
Malus domesticae0 - Interactor
- E. amylovora
Erwinia amylovorae1pathogen - Second interactor
- ϕEa46-1-A1e2biocontrol_agent
- Outcome
- bacteriophage-insensitive mutant (BIM)e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“which causes fire blight in apple and pear orchards”
e1“a bacteriophage-insensitive mutant (BIM) of E. amylovora”
e2“this study successfully created a BIM against the podovirus ϕEa46-1-A1”
Claim · model-written summary
The phage-insensitive E. amylovora mutant B6-2 carries a mutation in the rcsB gene.
- Taxon
- appleMalus domesticae0
- Material
- B6-2e3
- Gene
- rcsBe3
- Outcome
- mutatione3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“which causes fire blight in apple and pear orchards”
e3“The results revealed a mutation in strain B6-2 in the rcsB gene, which encodes a second regulator in the Rcs two-component phosphorelay system (TCS)”
Claim · model-written summary
The rcsB mutation downregulated amylovoran gene expression in strain B6-2, with an average log2 fold change of −4.35 across amsA-L.
- Taxon
- appleMalus domesticae0
- Treatment
- mutatione4
- Gene
- amsA-Le5
- Outcome
- amylovoran gene expressione4
- Direction
- downregulatione4
- Value
- −4.35e5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“which causes fire blight in apple and pear orchards”
e4“This mutation resulted in significant changes in the B6-2 BIM, including downregulation of amylovoran gene expression”
e5“an average log2 fold change of −4.35 across amsA-L”
Claim · model-written summary
The rcsB mutation visibly altered biofilm formation of strain B6-2.
- Taxon
- appleMalus domesticae0
- Outcome
- biofilm formatione6
- Qualifier
- visible alterationse6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“which causes fire blight in apple and pear orchards”
e6“visible alterations in biofilm formation”
Claim · model-written summary
The rcsB mutant was 22.4% more sensitive to streptomycin.
- Taxon
- appleMalus domesticae0
- Treatment
- streptomycine7
- Outcome
- sensitivity to antibioticse7
- Direction
- increasede7
- Value
- 22.4%e7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“which causes fire blight in apple and pear orchards”
e7“increased sensitivity to antibiotics (22.4% more sensitive to streptomycin)”
Claim · model-written summary
The rcsB mutation caused a loss of pathogenicity of E. amylovora on apple seedlings compared with the wildtype strain.
- Taxon
- apple seedlingMalus domesticae2
- Treatment
- mutatione4
- Outcome
- pathogenicitye2
- Direction
- losse2
- Comparator
- wildtype straine2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e4“This mutation resulted in significant changes in the B6-2 BIM, including downregulation of amylovoran gene expression”
e2“a loss of pathogenicity as assessed in an apple seedling virulence model in comparison to the wildtype strain”
Claim · model-written summary
The Rcs phosphorelay system, altered by the rcsB mutation, plays a critical role in phage resistance in E. amylovora.
- Taxon
- appleMalus domesticae0
- Interactor
- E. amylovoraErwinia amylovorae4pathogen
- Gene
- rcsBe3
- Outcome
- phage resistancee4
- Qualifier
- Rcs phosphorelay systeme4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“which causes fire blight in apple and pear orchards”
e3“The results revealed a mutation in strain B6-2 in the rcsB gene, which encodes a second regulator in the Rcs two-component phosphorelay system (TCS)”
e4“The findings presented in this study highlight the critical role of the Rcs phosphorelay system in phage resistance in E. amylovora”
The same questions in other papers
loss of function · molecular: expression · Malus domestica (apple)Positive and negative results
3 papers in the same direction as this paper · 11 in the opposite direction
- negative
- negative
- negative
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