Impact Factor

Hypothesis & Theory ARTICLE

Front. Plant Sci., 01 November 2011 | http://dx.doi.org/10.3389/fpls.2011.00075

At the frontier; RXLR effectors crossing the Phytophthora–host interface

  • 1 Laboratory of Phytopathology, Wageningen University, Wageningen, Netherlands
  • 2 Centre for BioSystems Genomics, Wageningen, Netherlands

Plants are constantly beset by pathogenic organisms. To successfully infect their hosts, plant pathogens secrete effector proteins, many of which are translocated to the inside of the host cell where they manipulate normal physiological processes and undermine host defense. The way by which effectors cross the frontier to reach the inside of the host cell varies among different classes of pathogens. For oomycete plant pathogens – like the potato late blight pathogen Phytophthora infestans – it has been shown that effector translocation to the host cell cytoplasm is dependent on conserved amino acid motifs that are present in the N-terminal part of effector proteins. One of these motifs, known as the RXLR motif, has a strong resemblance with a host translocation motif found in effectors secreted by Plasmodium species. These malaria parasites, that reside inside specialized vacuoles in red blood cells, make use of a specific protein translocation complex to export effectors from the vacuole into the red blood cell. Whether or not also oomycete RXLR effectors require a translocation complex to cross the frontier is still under investigation. For one P. infestans RXLR effector named IPI-O we have found a potential host target that could play a role in establishing the first contact between this effector and the host cell. This membrane spanning lectin receptor kinase, LecRK-I.9, interacts with IPI-O via the tripeptide RGD that overlaps with the RXLR motif. In animals, RGD is a well-known cell adhesion motif; it binds to integrins, which are membrane receptors that regulate many cellular processes and which can be hijacked by pathogens for either effector translocation or pathogen entry into host cells.

Keywords: RXLR–dEER, Phytophthora, effector, oomycetes, RGD, lectin receptor kinase, LecRK-I.9

Citation: Bouwmeester K, Meijer HJG and Govers F (2011) At the frontier; RXLR effectors crossing the Phytophthora–host interface. Front. Plant Sci. 2:75. doi: 10.3389/fpls.2011.00075

Received: 13 July 2011; Accepted: 17 October 2011;
Published online: 01 November 2011.

Edited by:

Giulia de Lorenzo, Sapienza Università di Roma, Italy

Reviewed by:

Christiane Gatz, Georg August Universität Göttingen, Germany
Guido van den Ackerveken, Utrecht University, Netherlands

Copyright: © 2011 Bouwmeester, Meijer and Govers. This is an open-access article subject to a non-exclusive license between the authors and Frontiers Media SA, which permits use, distribution and reproduction in other forums, provided the original authors and source are credited and other Frontiers conditions are complied with.

*Correspondence: Francine Govers, Laboratory of Phytopathology, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, Netherlands. e-mail: francine.govers@wur.nl