Pseudomonas syringae addresses distinct environmental challenges during plant infection through the coordinated deployment of polysaccharides

Krishna, Pilla Sankara, Woodcock, Stuart Daniel, Pfeilmeier, Sebastian, Bornemann, Stephen, Zipfel, Cyril and Malone, Jacob George (2022) Pseudomonas syringae addresses distinct environmental challenges during plant infection through the coordinated deployment of polysaccharides. Journal of Experimental Botany, 73 (7). 2206–2221. ISSN 0022-0957

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Abstract

Prior to infection, phytopathogenic bacteria face a challenging environment on the plant surface, where they are exposed to nutrient starvation and abiotic stresses. Pathways enabling surface adhesion, stress tolerance, and epi phytic survival are important for successful plant pathogenesis. Understanding the roles and regulation of these path ways is therefore crucial to fully understand bacterial plant infections. The phytopathogen Pseudomonas syringae pv. tomato (Pst) encodes multiple polysaccharides that are implicated in biofilm formation, stress survival, and virulence in other microbes. To examine how these polysaccharides impact Pst epiphytic survival and pathogenesis, we ana lysed mutants in multiple polysaccharide loci to determine their intersecting contributions to epiphytic survival and infection. In parallel, we used qRT–PCR to analyse the regulation of each pathway. Pst polysaccharides are tightly coordinated by multiple environmental signals. Nutrient availability, temperature, and surface association strongly af fect the expression of different polysaccharides under the control of the signalling protein genes ladS and cbrB and the second messenger cyclic-di-GMP. Furthermore, functionally redundant, combinatorial phenotypes were observed for several polysaccharides. Exopolysaccharides play a role in mediating leaf adhesion, while α-glucan and alginate together confer desiccation tolerance. Our results suggest that polysaccharides play important roles in overcoming environmental challenges to Pst during plant infection.

Item Type: Article
Additional Information: Funding: Research in the laboratories of JGM, CZ, and SB was supported by UK Research and Innovation- Biotechnology and Biological Sciences Research Council Norwich Research Park (UKRI-BBSRC) Institute Strategic Program Grants BB/J004553/1 (BIO), BB/J004561/1 (MET) and BBS/E/J/000PR9797 (Plant Health) to the John Innes Centre and The Sainsbury Laboratory. PSK was additionally supported by UKRI-BBSRC Grant BB/T004363/1. SDW was funded by a BBSRC Doctoral Training Partnership (BB/J014524/1) PhD studentship. SP was supported by a Norwich Research Park PhD studentship. Data availability: All data supporting the findings of this study are available within the paper and within its supplementary data published online. The data supporting the findings of this study and raw data used for making the graphs are available from the corresponding author, Jacob Malone, upon request.
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: LivePure Connector
Date Deposited: 09 May 2022 08:30
Last Modified: 09 May 2022 13:30
URI: https://ueaeprints.uea.ac.uk/id/eprint/84962
DOI: 10.1093/jxb/erab550

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