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In through the Out Door: A Functional Virulence Factor Secretion System Is Necessary for Phage Infection in Ralstonia
André da Silva Xavier1, Alessandra G de Melo2,3, Connor G Hendrich4
1Departamento de Fitopatologia, Instituto de Biotecnologia Aplicada à Agropecuária (BIOAGRO), Universidade Federal de Viçosagrid.12799.34, Viçosa, MG, Brazil.
Mbio
|October 31, 2022
Summary
Ralstonia solanacearum evolved resistance to phiAP1 phage by disabling its Type II Secretion System (T2SS). This resistance significantly reduced bacterial virulence, suggesting phages are a viable control strategy for bacterial wilt.
Area of Science:
- Microbiology
- Plant Pathology
- Virology
Background:
- Ralstonia solanacearum causes devastating bacterial wilt in crops.
- Bacteriophages (phages) are viruses that infect bacteria and can be used for biocontrol.
- Bacteria evolve resistance to phages through various mechanisms.
Purpose of the Study:
- Investigate how Ralstonia solanacearum develops resistance to the lytic phage phiAP1.
- Determine the role of the Type II Secretion System (T2SS) in phage resistance and infection.
- Assess the implications of phage resistance on bacterial virulence and fitness.
Main Methods:
- Generated and analyzed Bacteriophage Insensitive Mutants (BIMs) of R. solanacearum.
- Utilized genetic engineering to create specific mutations in the T2SS.
- Phenotypically characterized BIMs and assessed R. solanacearum virulence on tomato plants.
Main Results:
- The Type II Secretion System (T2SS) is crucial for phiAP1 phage infection.
- Functional T2SS, not just its presence, is required for phage sensitivity.
- Mutants resistant to phiAP1 exhibited significantly reduced virulence and fitness.
Conclusions:
- PhiAP1 phage infection requires a functional T2SS in R. solanacearum, possibly involving T2SS resetting.
- Phage resistance confers a substantial fitness cost, reducing bacterial virulence.
- Phages targeting the T2SS represent a promising, sustainable biocontrol strategy for bacterial wilt.
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