Plant NB-LRR signaling: upstreams and downstreams

Abstract

Plant disease resistance proteins commonly belong to the nucleotide binding-leucine rich repeat (NB-LRR) protein family. These specialized immune proteins mediate recognition of diverse pathogen-derived effector proteins and initiate potent defense responses. NB-LRRs exhibit a multidomain architecture and each domain appears to have discrete functions depending on the stage of NB-LRR signaling. Novel proteins that were found to interact with the core HSP90 chaperone complex regulate accumulation and activation of NB-LRR immune receptors. Recent studies have also advanced our understanding of how accessory proteins contribute to NB-LRR activation. The dynamic nature of NB-LRR localization to different subcellular compartments before and after activation suggests that NB-LRRs may activate immune responses in multiple parts of the cell. In this review we highlight recent advances in understanding NB-LRR function.

Transcriptomics of induced defense responses to greenbug aphid feeding in near isogenic wheat lines

“…Perception of feeding behavior by plants with R gene was shown to activate phytohormone, salicylic acid (SA)-dependent signaling cascade and callose deposition [14]. The detailed signaling cascades involving NB-LRR motif has been thoroughly summarized in the context of disease resistance [15,16] and plant-aphid interactions [2] suggesting that the induced defense responses involve multiple signal transduction pathways.…”

The Pseudomonas syringae Type III Effector AvrRpt2 Promotes Pathogen Virulence via Stimulating Arabidopsis Auxin/Indole Acetic Acid Protein Turnover

“…The signaling events activated by well-studied bacterial flagellin and elongation factor Tu include rapid receptor dimerization, phosphorylation, and ubiquitination, which lead to oxidative burst, stomatal closure, induction of defense-related genes, and accumulation of antimicrobial compounds. In addition to PTI, plants have also evolved resistance proteins that directly or indirectly recognize cognate pathogen-encoded effectors and result in cultivar-specific effector-triggered immunity often accompanied by localized programmed cell death or hypersensitive response (HR) and systemic defense signaling (DeYoung and Innes, 2006;Bent and Mackey, 2007;Elmore et al, 2011;Maekawa et al, 2011;Bonardi et al, 2012). In order to successfully colonize plant tissue and cause disease, pathogens need to avoid and/or suppress host immune systems and obtain nutrients before they can multiply to high levels.…”

The Chloroplastic Protein THF1 Interacts with the Coiled-Coil Domain of the Disease Resistance Protein N′ and Regulates Light-Dependent Cell Death

“…Structural analyses of NB-LRR proteins have indicated that the C-terminal LRR domain confers recognition specificity, while the central NB domain plays a role in regulation and possibly downstream signaling (Rairdan et al, 2008;Elmore et al, 2011;Takken and Goverse, 2012). The variable N termini have been implicated in at least two key NB-LRR functions.…”