Plant Immune Response Mechanisms in Pathogen Resistance

Plants deploy a multi-layered immune system to ward off a vast array of pathogens. The first layer, pattern-triggered immunity, is initiated when cell-surface receptors detect conserved microbial molecules, leading to ion fluxes, cell wall reinforcement and a burst of reactive oxygen species. To overcome this barrier, many pathogens secrete effectors that interfere with host defences. In response, plants have evolved intracellular nucleotide-binding leucine-rich repeat receptors that recognise these effectors directly or indirectly, a process known as effector-triggered immunity. Activation of these receptors commonly leads to localised programmed cell death, the hypersensitive response, and systemic signalling to prime distal tissues. Hormonal networks—including salicylic acid, jasmonic acid and abscisic acid—fine-tune these responses, balancing defence and growth. Recent advances have highlighted the importance of receptor localisation, dynamic protein-protein interactions and hormone-receptor crosstalk in determining the strength and specificity of resistance. Understanding these interconnected mechanisms is key to engineering durable disease resistance in crops.

Research from Nature Portfolio

Recent studies have uncovered a direct link between intracellular immune receptors and abscisic acid signalling. A specialised NLR receptor was shown to mimic a canonical abscisic acid sensor by binding the central PP2C-SnRK2 regulatory complex upon effector recognition. This interaction frees SnRK2 kinases from inhibition, triggering an abscisic acid-dependent antiviral response and revealing a new paradigm for how hormone pathways are activated by receptor conformational changes.

Innovative proximity-labelling approaches have been applied to dissect the regulatory networks surrounding NLR proteins. By fusing a biotin ligase to a viral-resistance NLR, researchers mapped its proximal interactome in living cells. This led to the discovery of a ubiquitin E3 ligase that directly binds the receptor’s signalling domain to limit its accumulation. Disruption of this negative regulator enhances resistance, demonstrating how post-translational control shapes receptor levels and immune outputs.

Plant Immune Response Mechanisms in Pathogen Resistance publication trend

The graph below shows the total number of articles in plant immune response mechanisms in pathogen resistance across all publications each year (not limited to Nature Index journals).

Technical terms

Pattern-triggered immunity (PTI): The basal defence response activated by recognition of conserved microbial motifs at the cell surface.

Effector-triggered immunity (ETI): A robust intracellular defence initiated when immune receptors detect pathogen-secreted effector proteins.

Nucleotide-binding leucine-rich repeat receptor (NLR): An intracellular sensor protein that recognises pathogen effectors and initiates immune signalling.

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

Abscisic acid (ABA): A plant hormone traditionally linked to stress responses, here shown to be co-opted by immune receptors.

Jasmonic acid (JA): A lipid-derived hormone that regulates defence against necrotrophic pathogens and herbivores.

References

1. A plant NLR receptor employs ABA central regulator PP2C-SnRK2 to activate antiviral immunity. Nature Communications (2024).
2. VvWRKY5 enhances white rot resistance in grape by promoting the jasmonic acid pathway. Horticulture Research (2023).
3. TurboID-based proximity labeling reveals that UBR7 is a regulator of N NLR immune receptor-mediated immunity. Nature Communications (2019).
4. Structure-Function Analysis of Barley NLR Immune Receptor MLA10 Reveals Its Cell Compartment Specific Activity in Cell Death and Disease Resistance. PLOS Pathogens (2012).
5. Recent Advances in Plant NLR Structure, Function, Localization, and Signaling. Frontiers in Immunology (2013).
6. Multiple Domain Associations within the Arabidopsis Immune Receptor RPP1 Regulate the Activation of Programmed Cell Death. PLOS Pathogens (2016).