Crying out for help with root exudates: adaptive mechanisms by which stressed plants assemble health-promoting soil microbiomes

Curr Opin Microbiol. 2019 Jun:49:73-82. doi: 10.1016/j.mib.2019.10.003. Epub 2019 Nov 13.


Plants employ immunological and ecological strategies to resist biotic stress. Recent evidence suggests that plants adapt to biotic stress by changing their root exudation chemistry to assemble health-promoting microbiomes. This so-called 'cry-for-help' hypothesis provides a mechanistic explanation for previously characterized soil feedback responses to plant disease, such as the development of disease-suppressing soils upon successive cultivations of take all-infected wheat. Here, we divide the hypothesis into individual stages and evaluate the evidence for each component. We review how plant immune responses modify root exudation chemistry, as well as what impact this has on microbial activities, and the subsequent plant responses to these activities. Finally, we review the ecological relevance of the interaction, along with its translational potential for future crop protection strategies.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Microbiota*
  • Plant Diseases / immunology
  • Plant Diseases / microbiology*
  • Plant Exudates / chemistry*
  • Plant Physiological Phenomena
  • Plant Roots / chemistry
  • Plant Roots / immunology
  • Plant Roots / microbiology*
  • Plants / chemistry
  • Plants / immunology
  • Plants / microbiology
  • Rhizosphere
  • Secondary Metabolism
  • Soil Microbiology*
  • Stress, Physiological*


  • Plant Exudates