Gene

Cell biology

Biology

Receptor

Immunity

Plant Immunity

Biochemistry

Computational biology

Genetics

Salicylic acid

Arabidopsis

Immune system

Biosynthesis

Mutant

Annual Review of Plant Biology

Salicylic acid (SA) is an essential plant defense hormone that promotes immunity against biotrophic and semibiotrophic pathogens. It plays crucial roles in basal defense and the amplification of local immune responses, as well as the establishment of systemic acquired resistance. During the past three decades, immense progress has been made in understanding the biosynthesis, homeostasis, perception, and functions of SA. This review summarizes the current knowledge regarding SA in plant immunity and other biological processes. We highlight recent breakthroughs that substantially advanced our understanding of how SA is biosynthesized from isochorismate, how it is perceived, and how SA receptors regulate different aspects of plant immunity. Some key questions in SA biosynthesis and signaling, such as how SA is produced via another intermediate, benzoic acid, and how SA affects the activities of its receptors in the transcriptional regulation of defense genes, remain to be addressed.

Salicylic Acid: Biosynthesis and Signaling