Structure of the activated ROQ1 resistosome directly recognizing the pathogen effector XopQ

TLDR

Tetrameric NLR immune receptors detect pathogen effectors and trigger plant immunity, and recent structural studies of two TIR‑NLRs—RPP1 from Arabidopsis and ROQ1 from Nicotiana—have elucidated their effector‑responsive tetrameric assemblies. Both groups found that effector binding induces tetrameric TIR‑NLRs to expose an NAD‑hydrolase active site, initiating NAD hydrolysis and triggering the immune response. Ma et al.

Abstract

Tetrameric immune receptors Nucleotide-binding/leucine-rich repeat (NLR) immune receptors detect pathogen effectors and trigger a plant's immune response. Two groups have now defined the structures of two NLRs that carry Toll-like interleukin-1 receptor (TIR) domains (TIR-NLRs) (see the Perspective by Tian and Li). Ma et al. studied the Arabidopsis thaliana TIR-NLR RPP1 (recognition of Peronospora parasitica 1) and its response to effectors from an oomycete pathogen. Martin et al. studied the Nicotiana benthamiana TIR-NLR ROQ1 (recognition of XopQ 1) and its response to the Xanthomonas effector. Both groups found that these TIR-NLRs formed tetramers that, when activated by binding to the pathogen effector, exposed the active site of a nicotinamide adenine dinucleoside (NAD) hydrolase. Thus, recognition of the pathogen effector initiates NAD hydrolysis and begins the immune response. Science , this issue p. eabe3069 , p. eabd9993 ; see also p. 1163