Structure, biochemical function, and signaling mechanism of plant NLRs

• Published in: Molecular plant Vol. 16; no. 1; pp. 75 - 95
• Main Authors: Wang, Jizong, Song, Wen, Chai, Jijie
• Format: Journal Article
• Language: English
• Published: England Elsevier Inc 02.01.2023
• Subjects: Ca2+ signaling; Ca2+-permeable channels; NLR; NLR Proteins; Plant Diseases; Plant Immunity; Plants; PRR; Receptors, Pattern Recognition; resistosome; second messenger; Signal Transduction; PRR; resistosome; Ca2+ signaling; NLR; Ca2+-permeable channels; second messenger; plant immunity; Ca(2+)-permeable channels; Ca(2+) signaling
• ISSN: 1674-2052; 1752-9867
• DOI: 10.1016/j.molp.2022.11.011

To counter pathogen invasion, plants have evolved a large number of immune receptors, including membrane-resident pattern recognition receptors (PRRs) and intracellular nucleotide-binding and leucine-rich repeat receptors (NLRs). Our knowledge about PRR and NLR signaling mechanisms has expanded significantly over the past few years. Plant NLRs form multi-protein complexes called resistosomes in response to pathogen effectors, and the signaling mediated by NLR resistosomes converges on Ca2+-permeable channels. Ca2+-permeable channels important for PRR signaling have also been identified. These findings highlight a crucial role of Ca2+ in triggering plant immune signaling. In this review, we first discuss the structural and biochemical mechanisms of non-canonical NLR Ca2+ channels and then summarize our knowledge about immune-related Ca2+-permeable channels and their roles in PRR and NLR signaling. We also discuss the potential role of Ca2+ in the intricate interaction between PRR and NLR signaling. Plant NLRs form resistosomes in response to pathogen effectors to initiate immune signaling. In this review, Wang et al. summarize recent findings concerning NLR resistosomes and discuss biochemical and structural mechanisms of how signaling mediated by different resistosomes converges on Ca2+ pathways. The potential roles of Ca2+ in mutual potentiation of NLR signaling and the signaling mediated by membrane-resident immune receptors are also discussed.