title: The role of effectors in nonhost resistance to filamentous plant pathogens.
abstract: In nature, most plants are resistant to a wide range of phytopathogens. However, mechanisms contributing to this so-called nonhost resistance (NHR) are poorly understood. Besides constitutive defenses, plants have developed two layers of inducible defense systems. Plant innate immunity relies on recognition of conserved pathogen-associated molecular patterns (PAMPs). In compatible interactions, pathogenicity effector molecules secreted by the invader can suppress host defense responses and facilitate the infection process. Additionally, plants have evolved pathogen-specific resistance mechanisms based on recognition of these effectors, which causes secondary defense responses. The current effector-driven hypothesis is that NHR in plants that are distantly related to the host plant is triggered by PAMP recognition that cannot be efficiently suppressed by the pathogen, whereas in more closely related species, nonhost recognition of effectors would play a crucial role. In this review we give an overview of current knowledge of the role of effector molecules in host and NHR and place these findings in the context of the model. We focus on examples from filamentous pathogens (fungi and oomycetes), discuss their implications for the field of plant-pathogen interactions and relevance in plant breeding strategies for development of durable resistance in crops.
authors.affiliation: Division of Plant Sciences, University of Dundee - The James Hutton Institute Dundee, UK.
authors.forename: Remco
authors.initials: R
authors.lastname: Stam
authors.affiliation: Cell and Molecular Sciences, The James Hutton Institute Dundee, UK.
authors.forename: Sophie
authors.initials: S
authors.lastname: Mantelin
authors.affiliation: Division of Plant Sciences, University of Dundee - The James Hutton Institute Dundee, UK.
authors.forename: Hazel
authors.initials: H
authors.lastname: McLellan
authors.affiliation: Division of Plant Sciences, University of Dundee - The James Hutton Institute Dundee, UK ; Cell and Molecular Sciences, The James Hutton Institute Dundee, UK.
authors.forename: Gaëtan
authors.initials: G
authors.lastname: Thilliez
keywords: effectors; filamentous plant pathogens; fungi; nonhost resistance; oomycetes