|VAN PELT, JOHAN - Utrecht University|
|PIETERSE, CORNE - Utrecht University|
|BAKKER, PETER - Utrecht University|
Submitted to: Rhizosphere 4; Program and Information Book
Publication Type: Abstract Only
Publication Acceptance Date: 4/20/2015
Publication Date: 6/21/2015
Citation: Weller, D.M., Van Pelt, J.A., Pieterse, C.M., Bakker, P.A. 2015. Induced systemic resistance in Arabidopsis against Pseudomonas syringae pv. tomato by disease suppressive soils. Rhizosphere 4; Program and Information Book. Abstract 87, Page 18.
Technical Abstract: Two-week-old Arabidopsis thaliana ecotype Col-0 seedlings were transferred into an autoclaved sand-soil mixture amended with 10% or 20% (weight/weight) soil that is suppressive to either take-all or Rhizoctonia root rot of wheat from fields in Washington State USA. These soils contain population sizes greater than 105 colony forming units per gram of wheat root of 2,4-diacetylphloroglucinol or phenazine-1-carboxylic acid-producing pseudomonads, respectively. Plants were challenge-inoculated with Pseudomonas syringae pv. tomato three weeks later. Both suppressive soils induced resistance in Arabidopsis against P. syringae similar to the well-studied Pseudomonas strains 417r, Q2-87 (produces 2,4-diacetylphloroglucinol) and 2-79 (produces phenazine-1-carboxylic acid). Pasteurization of the suppressive soils before adding them into the sand-soil mixture eliminated 2,4-diacetylphloroglucinol and phenazine-1-carboxylic acid- producing pseudomonads from the Arabidopsis rhizosphere and significantly reduced induced systemic resistance activity. However, population sizes of total aerobic culturable bacteria were similar in the rhizosphere of plants grown in the 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 phenazine-1-carboxylic acid to induce resistance.