Rhizosphere-Associated Pseudomonas Suppress Local Root Immune Responses by Gluconic Acid-Mediated Lowering of Environmental pH.

Autor: Yu K; Plant-Microbe Interactions, Institute of Environmental Biology, Department of Biology, Science4Life, Utrecht University, 3508 CH Utrecht, the Netherlands., Liu Y; Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada., Tichelaar R; Plant-Microbe Interactions, Institute of Environmental Biology, Department of Biology, Science4Life, Utrecht University, 3508 CH Utrecht, the Netherlands., Savant N; Plant-Microbe Interactions, Institute of Environmental Biology, Department of Biology, Science4Life, Utrecht University, 3508 CH Utrecht, the Netherlands., Lagendijk E; Koppert Biological Systems B.V., R&D Microbiology - Process Development, Veilingweg 14, 2651 BE Berkel en Rodenrijs, the Netherlands., van Kuijk SJL; Plant-Microbe Interactions, Institute of Environmental Biology, Department of Biology, Science4Life, Utrecht University, 3508 CH Utrecht, the Netherlands., Stringlis IA; Plant-Microbe Interactions, Institute of Environmental Biology, Department of Biology, Science4Life, Utrecht University, 3508 CH Utrecht, the Netherlands., van Dijken AJH; Plant-Microbe Interactions, Institute of Environmental Biology, Department of Biology, Science4Life, Utrecht University, 3508 CH Utrecht, the Netherlands., Pieterse CMJ; Plant-Microbe Interactions, Institute of Environmental Biology, Department of Biology, Science4Life, Utrecht University, 3508 CH Utrecht, the Netherlands., Bakker PAHM; Plant-Microbe Interactions, Institute of Environmental Biology, Department of Biology, Science4Life, Utrecht University, 3508 CH Utrecht, the Netherlands., Haney CH; Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada., Berendsen RL; Plant-Microbe Interactions, Institute of Environmental Biology, Department of Biology, Science4Life, Utrecht University, 3508 CH Utrecht, the Netherlands. Electronic address: r.l.berendsen@uu.nl.
Jazyk: angličtina
Zdroj: Current biology : CB [Curr Biol] 2019 Nov 18; Vol. 29 (22), pp. 3913-3920.e4. Date of Electronic Publication: 2019 Oct 24.
DOI: 10.1016/j.cub.2019.09.015
Abstrakt: The root microbiome consists of commensal, pathogenic, and plant-beneficial microbes [1]. Most members of the root microbiome possess microbe-associated molecular patterns (MAMPs) similar to those of plant pathogens [2]. Their recognition can lead to the activation of host immunity and suppression of plant growth due to growth-defense tradeoffs [3, 4]. We found that 42% of the tested root microbiota, including the plant growth-promoting rhizobacteria Pseudomonas capeferrum WCS358 [5, 6] and Pseudomonas simiae WCS417 [6, 7], are able to quench local Arabidopsis thaliana root immune responses that are triggered by flg22 [8], an immunogenic epitope of the MAMP flagellin [9], suggesting that this is an important function of the root microbiome. In a screen for WCS358 mutants that lost their capacity to suppress flg22-induced CYP71A12 pro :GUS MAMP-reporter gene expression, we identified the bacterial genes pqqF and cyoB in WCS358, which are required for the production of gluconic acid and its derivative 2-keto gluconic acid. Both WCS358 mutants are impaired in the production of these organic acids and consequently lowered their extracellular pH to a lesser extent than wild-type WCS358. Acidification of the plant growth medium similarly suppressed flg22-induced CYP71A12 pro :GUS and MYB51 pro :GUS expression, and the flg22-mediated oxidative burst, suggesting a role for rhizobacterial gluconic acid-mediated modulation of the extracellular pH in the suppression of root immunity. Rhizosphere population densities of the mutants were significantly reduced compared to wild-type. Collectively, these findings show that suppression of immune responses is an important function of the root microbiome, as it facilitates colonization by beneficial root microbiota.
(Copyright © 2019 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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