Protease Activity in Plant Defense Mechanisms

Proteases are key hydrolytic enzymes that orchestrate multiple layers of plant immunity, from the perception of microbial signatures to the execution of programmed cell death. In the extracellular apoplast, secreted proteases degrade pathogen-derived molecules and activate defence peptides, while intracellular proteases regulate hormone-mediated signalling cascades and systemic acquired resistance. Pathogens in turn secrete specialised inhibitors to neutralise host proteases, driving an evolutionary arms race that shapes both protease repertoires and inhibitor specificities. Advances in structural biology and activity profiling have revealed how proteolytic networks are remodelled during infection, underpinning global efforts to engineer crops with enhanced resilience against diverse pathogens.

Research from Nature Portfolio

Recent studies using AI structural modelling have predicted cross-kingdom interactions at the plant–pathogen interface, identifying novel small secreted proteins that inhibit key defence proteases such as the subtilase P69B. Experimental validation confirmed several microbial effectors obstruct active sites of chitinases and proteases, highlighting a conserved effector hub targeted by fungi, oomycetes and bacteria. This work not only uncovers diversified protease-inhibitor pairs shaped by co-evolution but also demonstrates the power of predictive frameworks to map intricate proteolytic networks.

Protease Activity in Plant Defense Mechanisms publication trend

The graph below shows the total number of articles in protease activity in plant defense mechanisms across all publications each year (not limited to Nature Index journals).

Technical terms

Protease: An enzyme that catalyses the hydrolysis of peptide bonds in proteins.

Hydrolase: A class of enzymes that use water to cleave chemical bonds, encompassing proteases and glycosidases.

Apoplast: The extracellular continuum of plant cell walls and intercellular spaces where defence molecules accumulate.

Effector: A pathogen-derived molecule that modulates host processes to promote infection.

Activity-based proteomics: A technique employing reactive probes to profile and quantify active enzymes within complex samples.

Subtilase: A family of serine proteases characterised by a subtilisin-like structural fold, often implicated in defence signalling.

References

1. AlphaFold-Multimer predicts cross-kingdom interactions at the plant-pathogen interface. Nature Communications (2023).
2. Activity‐based proteomics uncovers suppressed hydrolases and a neo‐functionalised antibacterial enzyme at the plant–pathogen interface. New Phytologist (2023).
3. The battle in the apoplast: further insights into the roles of proteases and their inhibitors in plant–pathogen interactions. Frontiers in Plant Science (2015).