Chaperone-Mediated Plant Immunity Mechanisms

Plant innate immunity relies on the precise folding, assembly and regulation of intracellular immune receptors and their signalling partners. Central to this process are molecular chaperones such as heat-shock protein 90 (HSP90) and co-chaperones including suppressor of G2 allele of skp1 (SGT1) and required for Mla12 resistance (RAR1). These proteins act in dynamic complexes to stabilise nucleotide-binding leucine-rich repeat (NLR) receptors, facilitate effector recognition and promote downstream defence responses. Upon pathogen challenge, chaperone assemblies ensure proper receptor conformations that trigger rapid ion fluxes, reactive oxygen species accumulation and transcriptional reprogramming. Co-chaperones bearing specialised domains—J-domains, cysteine-histidine-rich (CHORD) motifs and CS folds—fine-tune HSP90 ATPase activity and guide client loading. Emerging evidence highlights the nucleocytoplasmic redistribution of chaperone–receptor pairs as a regulatory switch that determines whether programmed cell death or localised defence is activated. Understanding these modules offers routes to enhance crop resilience against a broad spectrum of pests and pathogens.

Research from Nature Portfolio

Recent studies have highlighted the role of SGT1 as an essential co-chaperone in effector-induced immunity in pepper. It is transcriptionally upregulated upon Phytophthora capsici inoculation and cooperates with the calcium-associated sensor SRC2-1 to initiate hypersensitive cell death and reactive oxygen species accumulation. Detailed analyses revealed that the SGT1–SRC2-1 complex undergoes stimulus-dependent relocalisation from the plasma membrane and cytoplasm into the nucleus, a step that is critical for full activation of defence-associated genes. This work provides a molecular link between Ca2+ signalling, chaperone machinery and R protein-mediated immunity, emphasising the dynamic spatial control of co-chaperone interactions.

Chaperone-Mediated Plant Immunity Mechanisms publication trend

The graph below shows the total number of articles in chaperone-mediated plant immunity mechanisms across all publications each year (not limited to Nature Index journals).

Technical terms

Chaperone: A protein that assists the folding, assembly or stabilisation of other proteins without being part of the final structure.

Co-chaperone: A partner protein that modulates chaperone activity, client selection or subcellular targeting.

NLR receptor: An intracellular immune sensor with nucleotide-binding and leucine-rich repeat domains responsible for effector recognition.

Hypersensitive response (HR): A form of programmed cell death at infection sites that restricts pathogen spread.

Reactive oxygen species (ROS): Chemically reactive molecules derived from oxygen that function as signalling molecules and antimicrobial agents.

References

1. Molecular Chaperone Hsp90 Associates with Resistance Protein N and Its Signaling Proteins SGT1 and Rar1 to Modulate an Innate Immune Response in Plants*. Journal of Biological Chemistry (2003).
2. Structural Basis for Assembly of Hsp90-Sgt1-CHORD Protein Complexes: Implications for Chaperoning of NLR Innate Immunity Receptors. Molecular Cell (2010).
3. SGT1 is required in PcINF1/SRC2-1 induced pepper defense response by interacting with SRC2-1. Scientific Reports (2016).
4. Hsp90 Gene Is Required for Mi-1-Mediated Resistance of Tomato to the Whitefly Bemisia tabaci. Plants (2023).
5. Type I J-Domain NbMIP1 Proteins Are Required for Both Tobacco Mosaic Virus Infection and Plant Innate Immunity. PLOS Pathogens (2013).
6. Overexpression of the Prunus sogdiana NBS-LRR Subgroup Gene PsoRPM2 Promotes Resistance to the Root-Knot Nematode Meloidogyne incognita in Tobacco. Frontiers in Microbiology (2017).