Shiv D. Kale was a finalist for the 2011 New Phytologist Tansley Medal for excellence in plant science, which recognises an outstanding contribution to research in plant science by an individual in the early stages of their career; see the Editorial by Dolan, 193: 821–822.
Article first published online: 21 NOV 2011
© 2011 The Author. New Phytologist © 2011 New Phytologist Trust
Volume 193, Issue 4, pages 874–881, March 2012
How to Cite
Kale, S. D. (2012), Oomycete and fungal effector entry, a microbial Trojan horse. New Phytologist, 193: 874–881. doi: 10.1111/j.1469-8137.2011.03968.x
- Issue published online: 2 FEB 2012
- Article first published online: 21 NOV 2011
- Received: 15 July 2011, Accepted: 6 October 2011
- RXLR and RXLR-like
Oomycete and fungal symbionts have significant impacts on most commercially important crop and forest species, and on natural ecosystems, both negatively as pathogens and positively as mutualists. Symbiosis may be facilitated through the secretion of effector proteins, some of which modulate a variety of host defense mechanisms. A subset of these secreted proteins are able to translocate into host cells. In the oomycete pathogens, two conserved N-terminal motifs, RXLR and dEER, mediate translocation of effector proteins into host cells independent of any pathogen-encoded machinery. An expanded ‘RXLR-like’ motif [R/K/H]X[L/M/I/F/Y/W]X has been used to identify functional translocation motifs in host-cell-entering fungal effector proteins from pathogens and a mutualist. The RXLR-like translocation motifs were required for the fungal effectors to enter host cells in the absence of any pathogen-encoded machinery. Oomycete and fungal effectors with RXLR and RXLR-like motifs can bind phospholipids, specifically phosphatidylinositol-3-phosphate (PtdIns-3-P). Effector-PtdIns-3-P binding appears to mediate cell entry via lipid raft-mediated endocytosis, and could be blocked by sequestering cell surface PtdIns-3-P or by utilizing inositides that competitively inhibit effector binding to PtdIns-3-P. These findings suggest that effector blocking technologies could be developed and utilized in a variety of important crop species against a broad spectrum of plant pathogens.