Effector Specialization in a Lineage of the Irish Potato Famine Pathogen

See allHide authors and affiliations

Science  31 Jan 2014:
Vol. 343, Issue 6170, pp. 552-555
DOI: 10.1126/science.1246300

You are currently viewing the abstract.

View Full Text

Log in to view the full text

Log in through your institution

Log in through your institution

The Makings of a Choosy Pathogen

The oomycete Phytophthora infestans is responsible for potato blight. A closely related pathogen afflicts the 4 o'clock flower. To assess why such similar pathogens are restricted to one host or the other, Dong et al. (p. 552; see the Perspective by Coaker) analyzed similar effectors from both pathogens. The results suggest that the host specialization that led to evolutionary divergence depends on reciprocal single–amino acid changes that tailor the pathogen effector to a specific host protease that is being disabled. Thus, small changes can open the door for a pathogen to jump to another species of host and, itself, diversify into another species of pathogen.


Accelerated gene evolution is a hallmark of pathogen adaptation following a host jump. Here, we describe the biochemical basis of adaptation and specialization of a plant pathogen effector after its colonization of a new host. Orthologous protease inhibitor effectors from the Irish potato famine pathogen, Phytophthora infestans, and its sister species, Phytophthora mirabilis, which is responsible for infection of Mirabilis jalapa, are adapted to protease targets unique to their respective host plants. Amino acid polymorphisms in both the inhibitors and their target proteases underpin this biochemical specialization. Our results link effector specialization to diversification and speciation of this plant pathogen.

  • * Present address: Division of Plant Sciences, University of Dundee, Invergowrie, Dundee DD2 5DA, UK.

  • Present address: Center for Proteomics and Bioinformatics, School of Medicine, Case Western Reserve University, Cleveland, OH 44106 USA.

  • Present address: Plant Breeding, Genetics, and Biotechnology, International Rice Research Institute (IRRI), Los Baños, Laguna, Philippines.

  • § Present address: Department of Plant and Environmental Protection Sciences, University of Hawaii, Honolulu, HI 96822, USA.

  • || Present address: School of Life Sciences, Gibbet Hill Campus, The University of Warwick, Coventry, CV4 7AL, UK.

View Full Text

Stay Connected to Science