1. The stem rust effector protein AvrSr50 escapes Sr50 recognition by a substitution in a single surface-exposed residue
- Author
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Diana Ortiz, Jian Chen, Megan A. Outram, Isabel M.L. Saur, Narayana M. Upadhyaya, Rohit Mago, Daniel J. Ericsson, Stella Cesari, Chunhong Chen, Simon J. Williams, Peter N. Dodds, Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), Génétique et Amélioration des Fruits et Légumes (GAFL), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Australian National University (ANU), Max Planck Institute for Plant Breeding Research (MPIPZ), University of Cologne, Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine Universität Düsseldorf = Heinrich Heine University [Düsseldorf]-Max Planck Institute for Plant Breeding Research (MPIPZ)-Universität zu Köln = University of Cologne, Australian Synchrotron [Clayton], Plant Health Institute of Montpellier (UMR PHIM), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut Agro Montpellier, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Université de Montpellier (UM), Australian Research Council Future fellowship (FT200100135), Chinese Scholarship Council (CSC) postgraduate fellowship, Daimler and Benz Foundation, and European Project: 0742263(2008)
- Subjects
wheat resistance ,Physiology ,effector structure ,Basidiomycota ,resistance breakdown ,food and beverages ,Plant Science ,[SDV.BV.PEP]Life Sciences [q-bio]/Vegetal Biology/Phytopathology and phytopharmacy ,Plant Breeding ,stem rust ,Sr50 ,Triticum ,AvrSr50 ,Disease Resistance ,Plant Diseases ,effector evolution - Abstract
International audience; Pathogen effectors are crucial players during plant colonisation and infection. Plant resistance mostly relies on effector recognition to activate defence responses. Understanding how effector proteins escape from plant surveillance is important for plant breeding and resistance deployment. Here we examined the role of genetic diversity of the stem rust (Puccinia graminis f. sp. tritici (Pgt)) AvrSr50 gene in determining recognition by the corresponding wheat Sr50 resistance gene. We solved the crystal structure of a natural variant of AvrSr50 and used site-directed mutagenesis and transient expression assays to dissect the molecular mechanisms explaining gain of virulence. We report that AvrSr50 can escape recognition by Sr50 through different mechanisms including DNA insertion, stop codon loss or by amino-acid variation involving a single substitution of the AvrSr50 surface-exposed residue Q121. We also report structural homology of AvrSr50 to cupin superfamily members and carbohydrate-binding modules indicating a potential role in binding sugar moieties. This study identifies key polymorphic sites present in AvrSr50 alleles from natural stem rust populations that play important roles to escape from Sr50 recognition. This constitutes an important step to better understand Pgt effector evolution and to monitor AvrSr50 variants in natural rust populations.
- Published
- 2022