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Role of Alternative Elicitor Transporters in the Onset of Plant Host Colonization by Streptomyces scabiei 87-22

Authors :
Isolde M. Francis
Danica Bergin
Benoit Deflandre
Sagar Gupta
Joren J. C. Salazar
Richard Villagrana
Nudzejma Stulanovic
Silvia Ribeiro Monteiro
Frédéric Kerff
Rosemary Loria
Sébastien Rigali
Source :
Biology, Vol 12, Iss 2, p 234 (2023)
Publication Year :
2023
Publisher :
MDPI AG, 2023.

Abstract

Plant colonization by Streptomyces scabiei, the main cause of common scab disease on root and tuber crops, is triggered by cello-oligosaccharides, cellotriose being the most efficient elicitor. The import of cello-oligosaccharides via the ATP-binding cassette (ABC) transporter CebEFG-MsiK induces the production of thaxtomin phytotoxins, the central virulence determinants of this species, as well as many other metabolites that compose the ‘virulome’ of S. scabiei. Homology searches revealed paralogues of the CebEFG proteins, encoded by the cebEFG2 cluster, while another ABC-type transporter, PitEFG, is encoded on the pathogenicity island (PAI). We investigated the gene expression of these candidate alternative elicitor importers in S. scabiei 87-22 upon cello-oligosaccharide supply by transcriptomic analysis, which revealed that cebEFG2 expression is highly activated by both cellobiose and cellotriose, while pitEFG expression was barely induced. Accordingly, deletion of pitE had no impact on virulence and thaxtomin production under the conditions tested, while the deletion of cebEFG2 reduced virulence and thaxtomin production, though not as strong as the mutants of the main cello-oligosaccharide transporter cebEFG1. Our results thus suggest that both ceb clusters participate, at different levels, in importing the virulence elicitors, while PitEFG plays no role in this process under the conditions tested. Interestingly, under more complex culture conditions, the addition of cellobiose restored thaxtomin production when both ceb clusters were disabled, suggesting the existence of an additional mechanism that is involved in sensing or importing the elicitor of the onset of the pathogenic lifestyle of S. scabiei.

Details

Language :
English
ISSN :
20797737
Volume :
12
Issue :
2
Database :
Directory of Open Access Journals
Journal :
Biology
Publication Type :
Academic Journal
Accession number :
edsdoj.5fb8131551f44d2915ac8e4a1d32471
Document Type :
article
Full Text :
https://doi.org/10.3390/biology12020234