The major function of salicylic acid is

✅ Explanation: Salicylic acid (SA) is a key signaling molecule in plants involved in local and systemic defense responses against pathogens. It plays a crucial role in activating various defense mechanisms, such as the production of pathogenesis-related proteins, the hypersensitive response (localized cell death at the infection site), and the establishment of systemic acquired resistance (SAR), which provides long-lasting protection against a broad spectrum of pathogens.