Salicylic acid (SA) is a ubiquitous plant hormone with a long history in human

civilization1,2 . Because of the central role of SA in orchestrating plant pathogen

defence, understanding SA biosynthesis is fundamental to plant immunity research

and crop improvement. Isochorismate-derived SA biosynthesis has been well

defined in Arabidopsis. However, increasing evidence suggests a crucial function for

phenylalanine-derived SA biosynthesis in many other plant species1 . Here we reveal

the phenylalanine-derived SA biosynthetic pathway in rice by identifying three

dedicated enzymes — peroxisomal benzoyl-CoA:benzyl alcohol benzoyltransferase

(BEBT), the endoplasmic reticulum-associated cytochrome P450 enzyme

benzylbenzoate hydroxylase (BBH), and cytosolic benzylsalicylate esterase (BSE)

that sequentially convert benzoyl-CoA to benzylbenzoate, benzylsalicylate and SA.

The pathogen-induced gene expression pattern and SA biosynthetic functions of this

triple-enzyme module are conserved in diverse plants. This work fills a major knowledge

gap in the biosynthesis of a key plant defence hormone, establishing a foundation for

new strategies to create disease-resistant crops.