Salicylic acid and jasmonic acid in plant immunity.

Salicylic acid (SA) and jasmonic acid (JA) are the two most important phytohormones in plant immunity. While SA plays pivotal roles in local and systemic acquired resistance (SAR) against biotrophic pathogens, JA, on the other hand, contributes to defense against necrotrophic pathogens, herbivores, and induced systemic resistance (ISR). Over the past 30 years, extensive research has elucidated the biosynthesis, metabolism, physiological functions, and signaling of both SA and JA. Here, we present an overview of signaling pathways of SA and JA and how they interact with each other to fine-tune plant defense responses.