Journal article
Factors impacting the activity of 2,4-diacetylphloroglucinol-producing Pseudomonas fluorescens against take-all of wheat
Soil biology & biochemistry, Vol.54, pp.48-56
11/2012
Handle:
https://hdl.handle.net/2376/101049
Abstract
Take-all, caused by Gaeumannomyces graminis var. tritici, is an important soilborne disease of wheat worldwide. Pseudomonas fluorescens producing the antibiotic 2,4-diacetylphloroglucinol (2,4-DAPG) are biocontrol agents of take-all and provide natural suppression of the disease during wheat monoculture known as take-all decline. To identify factors that could contribute to the effectiveness of 2,4-DAPG producers in take-all suppression, P. fluorescens strains Q8r1-96 (genotype D) and Q2-87V1 (genotype B; reduced antibiotic production) were tested against three pathogen isolates differing in sensitivity to 2,4-DAPG (LD5, ARS-A1 and R3-111a-1) and two wheat cultivars (Tara and Buchanan). The antibiotic sensitivity of the pathogen and cultivar significantly affected the level of take-all suppression by Q8r1-96 and Q2-87V1; suppression was greatest with LD5 and Tara. Q8r1-96 suppressed ARS-A1 and R3-111a-1 on Tara but not Buchanan, and Q2-87V1 failed to suppress either pathogen isolate on either cultivar. Q8r1-96 colonized the rhizosphere of Tara and Buchanan grown in soil similarly, but 2,4-DAPG accumulation was higher on the roots of Buchanan than Tara. 2,4-DAPG at 7.5 μg mL−1 reduced the growth of roots of both cultivars, and 10 μg mL−1 caused brown necrosis and tissue collapse of seedling roots and reduced root hair development. The half-life of 2,4-DAPG in the rhizosphere was estimated to be 0.25 days. These results suggest that several interconnected factors including sensitivity of G. graminis var. tritici to 2,4-DAPG, wheat cultivar, fluctuations in populations of 2,4-DAPG producers, and antibiotics accumulation in the rhizosphere will impact the robustness of take-all suppression by P. fluorescens in the field.
► We examine factors contributing to the effectiveness of biocontrol of a root disease of wheat. ► Wheat cultivars show differential support of antibiotic production and biocontrol. ► Biocontrol antibiotics can damage wheat roots. ► This study will help improve understanding of disease suppressive soils.
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Details
- Title
- Factors impacting the activity of 2,4-diacetylphloroglucinol-producing Pseudomonas fluorescens against take-all of wheat
- Creators
- Youn-Sig Kwak - Department of Plant Pathology, Washington State University, Pullman, WA 99164-6430, USARobert F Bonsall - Department of Plant Pathology, Washington State University, Pullman, WA 99164-6430, USAPatricia A Okubara - United States Department of Agriculture, Agricultural Research Service, Root Disease and Biological Control Research Unit, Pullman, WA 99164-6430, USATimothy C Paulitz - United States Department of Agriculture, Agricultural Research Service, Root Disease and Biological Control Research Unit, Pullman, WA 99164-6430, USALinda S Thomashow - United States Department of Agriculture, Agricultural Research Service, Root Disease and Biological Control Research Unit, Pullman, WA 99164-6430, USADavid M Weller - United States Department of Agriculture, Agricultural Research Service, Root Disease and Biological Control Research Unit, Pullman, WA 99164-6430, USA
- Publication Details
- Soil biology & biochemistry, Vol.54, pp.48-56
- Academic Unit
- Plant Pathology, Department of
- Publisher
- Elsevier Ltd
- Identifiers
- 99900546533701842
- Language
- English
- Resource Type
- Journal article