Integrity of the Post-LRR Domain Is Required for TIR-NB-LRR Function

Plants trigger appropriate defense responses, notably, through intracellular nucleotide-binding (NB) and leucine-rich repeat (LRR)-containing receptors (NLRs) that detect secreted pathogen effector proteins. In NLR resistance genes, the toll/interleukin-1 receptor (TIR)-NB-LRR proteins (TNLs) are an important subfamily, out of which approximately half members carry a post-LRR (PL) domain unknown role. We first investigated requirement PL for TNL-mediated immune response by mutating most conserved amino acids across domains Arabidopsis thaliana TNLs. identified several in RPS4, required its ability to hypersensitive AvrRps4 Nicotiana tabacum transient assay. Mutating corresponding within tobacco TNL gene N also affected function. Consequently, our results indicate integrity at positions is crucial least two unrelated then tested specificity function swapping between paralogs RPS4 RPS4B. Our suggest involved their pair specificity, ‘off state’ stability, complex activation. Considering genetically paired TNLs, we finally compared TIR sensor executor sequences, respectively. While from executors present complete motifs, sensors showed lack conservation with degenerated motifs. here provide contribution functional analysis order decipher role [Formula: see text] Copyright © 2021 The Author(s). This open access article distributed under CC BY-NC-ND 4.0 International license .