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Combining in vitro and in vivo screening to identify efficient Pseudomonas biocontrol strains against the phytopathogenic bacterium Ralstonia solanacearum
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  • Sophie Clough,
  • Alexandre Jousset,
  • John Elphinstone,
  • Ville‐Petri Friman
Sophie Clough
University of York

Corresponding Author:[email protected]

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Alexandre Jousset
Utrecht University
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John Elphinstone
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Ville‐Petri Friman
University of York
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While plant pathogens are traditionally controlled using synthetic agrochemicals the availability of commercial bactericides is still limited. One potential control strategy could be the use of plant-growth-promoting bacteria (PGPBs) to suppress pathogens via resource competition or the production of antimicrobial compounds. This study aimed to conduct in vitro and in vivo screening of eight Pseudomonas strains against Ralstonia solanacearum (the causative agent of bacterial wilt) and to investigate underlying mechanisms of potential pathogen suppression. We found that inhibitory effects were Pseudomonas strain-specific, with strain CHA0 showing the highest pathogen suppression. Genomic screening identified 2, 4-diacetylphloroglucinol (DAPG), pyoluteorin, and orfamides A and B secondary metabolite clusters in the genomes of the most inhibitory strains, which were investigated further. While all these compounds suppressed R. solanacearum growth, only Orfamide A was produced in the growth media based on mass spectrometry. Moreover, orfamide variants extracted from Pseudomonas cultures showed high pathogen suppression. Using the Micro Tom tomato cultivar, it was found that CHA0 could reduce bacterial wilt disease incidence with one of the two tested pathogen strains. Together, these findings suggest that a better understanding of Pseudomonas-Ralstonia interactions in the rhizosphere is required to successfully translate in vitro findings into agricultural applications.
02 Feb 2022Submitted to MicrobiologyOpen
04 Feb 2022Submission Checks Completed
04 Feb 2022Assigned to Editor
10 Feb 2022Reviewer(s) Assigned
23 Feb 2022Review(s) Completed, Editorial Evaluation Pending
24 Feb 2022Editorial Decision: Revise Minor
14 Mar 20221st Revision Received
15 Mar 2022Submission Checks Completed
15 Mar 2022Assigned to Editor
16 Mar 2022Review(s) Completed, Editorial Evaluation Pending
16 Mar 2022Reviewer(s) Assigned
31 Mar 2022Editorial Decision: Accept