European Journal of Plant Pathology

, Volume 113, Issue 4, pp 417–435

Effect of Organic Management of Soils on Suppressiveness to Gaeumannomyces graminis var. tritici and its Antagonist, Pseudomonas fluorescens

  • Gerbert A. Hiddink
  • Ariena H. C. van Bruggen
  • Aad J. Termorshuizen
  • Jos M. Raaijmakers
  • Alexander V. Semenov
Article

DOI: 10.1007/s10658-005-5402-7

Cite this article as:
Hiddink, G.A., van Bruggen, A.H.C., Termorshuizen, A.J. et al. Eur J Plant Pathol (2005) 113: 417. doi:10.1007/s10658-005-5402-7

Abstract

Organic management of soils is generally considered to reduce the incidence and severity of plant diseases caused by soil-borne pathogens. In this study, take-all severity on roots of barley and wheat, caused by Gaeumannomyces graminis var. tritici, was significantly lower in organically-managed than in conventionally-managed soils. This effect was more pronounced on roots of barley and wheat plants grown in a sandy soil compared to a loamy organically-managed soil. Fluorescent Pseudomonas spp. and in particular phlD+ pseudomonads, key factors in the take-all decline phenomenon, were represented at lower population densities in organically-managed soils compared to conventionally-managed soils. Furthermore, organic management adversely affected the initial establishment of introduced phlD+P. fluorescens strain Pf32-gfp, but not its survival. In spite of its equal survival rate in organically- and conventionally-managed soils, the efficacy of biocontrol of take-all disease by introduced strain Pf32-gfp was significantly stronger in conventionally-managed soils than in organically-managed soils. Collectively, these results suggest that phlD+Pseudomonas spp. do not play a critical role in the take-all suppressiveness of the soils included in this study. Consequently, the role of more general mechanisms involved in take-all suppressiveness in the organically-managed soils was investigated. The higher microbial activity found in the organically-managed sandy soil combined with the significantly lower take-all severity suggest that microbial activity plays, at least in part, a role in the take-all suppressiveness in the organically-managed sandy soil. The significantly different bacterial composition, determined by DGGE analysis, in organically-managed sandy soils compared to the conventionally-managed sandy soils, point to a possible additional role of specific bacterial genera that limit the growth or activity of the take-all pathogen.

Keywords

bacterial diversitydisease suppressionorganic agriculturetake-all suppressivenessPseudomonas

Abbreviations

2,4-DAPG

2,4-diacetylphloroglucinol

CFU

colony forming units

Ggt

Gaeumannomyces graminis var. tritici

Pf32-gfp

Pseudomonas fluorescens strain (Pf32) gfp tagged

Copyright information

© Springer 2005

Authors and Affiliations

  • Gerbert A. Hiddink
    • 1
  • Ariena H. C. van Bruggen
    • 1
  • Aad J. Termorshuizen
    • 1
  • Jos M. Raaijmakers
    • 2
  • Alexander V. Semenov
    • 1
  1. 1.Biological Farming Systems GroupWageningen UniversityWageningenThe Netherlands
  2. 2.Laboratory of PhytopathologyWageningen UniversityWageningenThe Netherlands