EMD-50863

Single-particle
3.8 Å
EMD-50863 Deposition: 03/07/2024
Map released: 12/02/2025
Last modified: 26/02/2025
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links

EMD-50863

The barley MLA13-AVRA13 heterodimer

EMD-50863

Single-particle
3.8 Å
EMD-50863 Deposition: 03/07/2024
Map released: 12/02/2025
Last modified: 26/02/2025
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Sample Organism: Hordeum vulgare, Blumeria graminis
Sample: MLA13-AVRA13 heterodimer complex
Fitted models: 9fyc (Avg. Q-score: 0.327)

Deposition Authors: Behrmann E , Schulze-Lefert P , Flores-Ibarra A , Lawson AW
The barley MLA13-AVR A13 heterodimer reveals principles for immunoreceptor recognition of RNase-like powdery mildew effectors.
PUBMED: 39948409
DOI: doi:10.1038/s44318-025-00373-9
ISSN: 1460-2075
ASTM: EMJODG
Abstract:
Co-evolution between cereals and pathogenic grass powdery mildew fungi is exemplified by sequence diversification of an allelic series of barley resistance genes encoding Mildew Locus A (MLA) nucleotide-binding leucine-rich repeat (NLR) immunoreceptors with an N-terminal coiled-coil domain (CNLs). Each immunoreceptor recognises a matching, strain-specific powdery mildew effector encoded by an avirulence gene (AVRa). We present here the cryo-EM structure of barley MLA13 in complex with its cognate effector AVRA13-1. The effector adopts an RNase-like fold when bound to MLA13 in planta, similar to crystal structures of other RNase-like AVRA effectors unbound to receptors. AVRA13-1 interacts via its basal loops with MLA13 C-terminal leucine-rich repeats (LRRs) and the central winged helix domain (WHD). Co-expression of structure-guided MLA13 and AVRA13-1 substitution variants show that the receptor-effector interface plays an essential role in mediating immunity-associated plant cell death. Furthermore, by combining structural information from the MLA13-AVRA13-1 heterocomplex with sequence alignments of other MLA receptors, we engineered a single amino acid substitution in MLA7 that enables expanded effector detection of AVRA13-1 and the virulent variant AVRA13-V2. In contrast to the pentameric conformation of previously reported effector-activated CNL resistosomes, MLA13 was purified and resolved as a stable heterodimer from an in planta expression system. Our study suggests a common structural principle for RNase-like effector binding to MLAs and highlights the utility of structure-guided engineering of plant immune receptors for broadening their pathogen effector recognition capabilities.