Systemin plays a crucial role in plant defense mechanisms. It is a signaling peptide that activates systemic acquired resistance (SAR) in plants, helping them respond to herbivore attacks and pathogen infections. When a plant is wounded, systemin is released and triggers the production of defensive compounds, such as proteinase inhibitors, which deter pests and limit further damage. This peptide is particularly studied in tomato plants, where it enhances the plant's ability to protect itself against insect herbivory. Researchers are exploring its potential in agricultural biotechnology to develop crops with improved resistance to pests and diseases, reducing the need for chemical pesticides.