7MQQ

Structure of an allelic variant of Puccinia graminis f. sp. tritici (Pgt) effector AvrSr50 (QCMJC)

Summary for 7MQQ

• Entry DOI: 10.2210/pdb7mqq/pdb
• Descriptor: Stem rust effector protein AvrSr50, MAGNESIUM ION (3 entities in total)
• Functional Keywords: effector, stem rust, unknown function
• Biological source: Puccinia graminis f. sp. tritici
• Total number of polymer chains: 1
• Total formula weight: 13211.28

Authors

Outram, M.A.,Ericsson, D.J.,Williams, S.J. (deposition date: 2021-05-06, release date: 2022-02-16, Last modification date: 2024-04-03)

Primary citation

Ortiz, D.,Chen, J.,Outram, M.A.,Saur, I.M.L.,Upadhyaya, N.M.,Mago, R.,Ericsson, D.J.,Cesari, S.,Chen, C.,Williams, S.J.,Dodds, P.N.
The stem rust effector protein AvrSr50 escapes Sr50 recognition by a substitution in a single surface-exposed residue.
New Phytol., 234:592-606, 2022

PubMed Abstract: 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.

PubMed: 35107838
DOI: 10.1111/nph.18011

Experimental method

X-RAY DIFFRACTION (1.15 Å)