Silenced cutters: mechanisms and effects of protease inhibition in plant–pathogen interactions

Proteases are essential enzymes in plants that play multiple roles in immunity, including molecular recognition, programmed cell death, and the degradation of pathogen proteins. During plant-pathogen interactions, both organisms have evolved mechanisms to regulate protease activity. Plants produce specific inhibitors to prevent excessive or harmful proteolysis, while pathogens counteract these defences by deploying molecules that block proteases and weaken plant immunity. Despite significant progress in understanding protease function, many regulatory mechanisms remain unexplored. This review examines the roles of endoproteases in plant responses to biotic stress and the diverse strategies employed by both plants and pathogens to modulate their activity. We discuss known protease inhibition mechanisms and highlight emerging methodologies that offer new insights into protease regulation. Additionally, we explore biotechnological applications, including genetic engineering and chemical inhibitors, aimed at enhancing plant resistance to pathogens. By integrating current knowledge with innovative research tools, we can uncover novel protease regulatory pathways and develop new strategies to improve plant resilience. Understanding these mechanisms not only advances fundamental plant biology but also holds potential for sustainable agricultural practices in the face of evolving pathogen threats.