Early changes in apoplast composition associated with defence and disease in interactions between Phaseolus vulgaris and the halo blight pathogen Pseudomonas syringae Pv. phaseolicola

O'Leary, Brendan M.; Neale, Helen C.; Geilfus, Christoph-Martin; Jackson, Robert W.; Arnold, Dawn L.; Preston, Gail M.

Abstract

© 2016 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd. The apoplast is the arena in which endophytic pathogens such as Pseudomonas syringae grow and interact with plant cells. Using metabolomic and ion analysis techniques, this study shows how the composition of Phaseolus vulgaris leaf apoplastic fluid changes during the first six hours of compatible and incompatible interactions with two strains of P. syringae pv. phaseolicola (Pph) that differ in the presence of the genomic island PPHGI-1. Leaf inoculation with the avirulent island-carrying strain Pph 1302A elicited effector-triggered immunity (ETI) and resulted in specific changes in apoplast composition, including increases in conductivity, pH, citrate, γ-aminobutyrate (GABA) and K+, that are linked to the onset of plant defence responses. Other apoplastic changes, including increases in Ca2+, Fe2/3+ Mg2+, sucrose, β-cyanoalanine and several amino acids, occurred to a relatively similar extent in interactions with both Pph 1302A and the virulent, island-less strain Pph RJ3. Metabolic footprinting experiments established that Pph preferentially metabolizes malate, glucose and glutamate, but excludes certain other abundant apoplastic metabolites, including citrate and GABA, until preferred metabolites are depleted. These results demonstrate that Pph is well-adapted to the leaf apoplast metabolic environment and that loss of PPHGI-1 enables Pph to avoid changes in apoplast composition linked to plant defences.

• Journal Article Type: Article
• Acceptance Date: May 23, 2016
• Online Publication Date: Jul 25, 2016
• Publication Date: Oct 1, 2016
• Deposit Date: Jun 9, 2016
• Publicly Available Date: Nov 18, 2016
• Journal: Plant Cell and Environment
• Print ISSN: 0140-7791
• Electronic ISSN: 1365-3040
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 39
• Issue: 10
• Pages: 2172-2184
• DOI: https://doi.org/10.1111/pce.12770
• Keywords: Pseudomonas syringae, leaf apoplast, apoplastic washing fluid, citrate, GABA, Phaseolus vulgaris, 17 metabolomics, metabolic footprinting, plant-microbe interactions, plant defence response
• Public URL: https://uwe-repository.worktribe.com/output/907651
• Publisher URL: http://dx.doi.org/10.1111/pce.12770
• Additional Information: Additional Information : This is the peer reviewed version of the following article: O'Leary, B., Neale, H., Geilfus, C.-M., Jackson, R. W., Arnold, D. L. and Preston, G. (2016) Early changes in apoplast composition associated with defence and disease in interactions between Phaseolus vulgaris and the halo blight pathogen Pseudomonas syringae pv. phaseolicola. Plant, Cell & Environment. ISSN 0140-7791, which has been published in final form at http://dx.doi.org/10.1111/pce.12770. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.
• Contract Date: Jun 9, 2016