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ARS Home » Pacific West Area » Pullman, Washington » WHGQ » Research » Publications at this Location » Publication #406183
Research Project: Ecology and Genomics of Soilborne Pathogens, Beneficial Microbes, and the Microbiome of Wheat, Barley, and Biofuel Brassicas

Location: Wheat Health, Genetics, and Quality Research

Title: Disease-suppressive soils induce systemic resistance in Arabidopsis thaliana against Pseudomonas syringae pv. tomato

Author
item Weller, David
item VAN PELT, JOHAN - Utrecht University
item Thomashow, Linda
item MAVRODI, DMITRI - University Of Southern Mississippi
item MAVRODI, OLGA - University Of Southern Mississippi
item PIETERSE, CORNE - Utrecht University
item BAKKER, PETER - Utrecht University

Submitted to: PhytoFrontiers
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/11/2024
Publication Date: 5/23/2024
Citation: Weller, D.M., van Pelt, J.A., Thomashow, L.S., Mavrodi, D.V., Mavrodi, O., Pieterse, C.M., Bakker, P.A. 2024. Disease-suppressive soils induce systemic resistance in Arabidopsis thaliana against Pseudomonas syringae pv. tomato. PhytoFrontiers. https://doi.org/10.1094/PHYTOFR-02-24-0012-R.
DOI: https://doi.org/10.1094/PHYTOFR-02-24-0012-R

Interpretive Summary: Suppressive soils are soils that have the ability to reduce or suppress soilborne pathogens because of specific microorganism present in the soil microbiome. Take-all decline (TAD) is a example of a suppressive soil that develops during wheat monoculture and results in the suppression of take-all disease of wheat, caused by Gaeumannomyces tritici. The suppressiveness of a TAD soil results from the build-up of 2,4-diacetylphloroglucinol (DAPG)-producing Pseudomonas strains on wheat roots during wheat monoculture. DAPG is a broad spectrum antibiotic that is active against a wide range of organisms including plant-pathogenic bacteria, fungi, and nematodes. In this paper, we show that a TAD soil is able to induced resistance in the model plant Arabidopsis thaliana against a foliar disease caused by Pseudomonas syringae pv tomato. DAPG-producing Pseudomonas strains, naturally present in the TAD soil, are the basis of the induced resistance. This work shows that suppressive soils can have a broader role in plant protection by inducing resistance mechanisms in the plant against foliar pathogens.

Technical Abstract: Arabidopsis thaliana accession Col-0 seedlings were transferred into an autoclaved sand-soil mixture amended with either 10 or 20% (weight/weight) soil from fields in Washington State USA that are suppressive to take-all or Rhizoctonia root rot of wheat. Three weeks after transplanting, these plants had population sizes of 2,4-diacetylphloroglucinol (DAPG) or phenazine-1-carboxylic acid (PCA)-producing pseudomonads of greater than log 5 colony forming units per gram fresh weight of root + rhizosphere soil. When the Arabidopsis plants were challenge-inoculated with Pseudomonas syringae pv. tomato, both soils displayed induced systemic resistance in the leaves against the disease to a level similar to that induced by Pseudomonas simiae WCS417r, P. fluorescens Q2-87 (DAPG+) and P. synxantha 2-79 (PCA+). Pasteurization of the wheat field soils before adding them into the sand-soil mixture eliminated DAPG and PCA-producing pseudomonads from the Arabidopsis rhizosphere and significantly reduced induced systemic resistance activity. However, population sizes of total culturable heterotrophic aerobic bacteria were similar in the rhizosphere of plants grown in mixes with pasteurized and raw suppressive soils. This is the first report of induced systemic resistance activity by take-all and Rhizoctonia suppressive soils and the ability of a PCA-producing bacterium to induce resistance.