Evidence for a diffusible factor that induces susceptibility in the Colletotrichum–maize disease interaction

Authors

  • Maria F. Torres,

    1. Department of Plant Pathology, University of Kentucky, Lexington, KY, USA
    Current affiliation:
    1. Functional Genomics Laboratory, Weill Cornell Medical College—Qatar, Cornell University, Qatar Foundation-Education City, Doha, Qatar
    Search for more papers by this author
  • Diego F. Cuadros,

    1. Infectious Disease Epidemiology Group, Weill Cornell Medical College—Qatar, Qatar Foundation, Education City, Doha, Qatar
    2. Department of Public Health, Weill Cornell Medical College, Cornell University, New York, NY, USA
    Search for more papers by this author
  • Lisa J. Vaillancourt

    Corresponding author
    1. Department of Plant Pathology, University of Kentucky, Lexington, KY, USA
    Search for more papers by this author

Summary

Colletotrichum graminicola, the causal agent of maize anthracnose, is a hemibiotrophic fungus that initially infects living host cells via primary hyphae surrounded by a membrane. A nonpathogenic mutant disrupted in a gene encoding a component of the signal peptidase complex, and believed to be deficient in protein processing and secretion, regained pathogenicity when it was inoculated onto maize leaf sheaths close to the wild-type fungus. Evidence is presented suggesting that the wild-type produces a diffusible factor(s) that induces the localized susceptibility of host cells at the borders of expanding colonies, causing them to become receptive to biotrophic invasion. The induced susceptibility effect is limited to a distance of approximately eight cells from the edge of the wild-type colony, is dosage dependent and is specific to C. graminicola.

Ancillary