Salicylic acid: Biosynthesis, metabolism and physiological role in plants

Abstract

Salicylic acid (SA) is a phenolic derivative, distributed in a wide range of plant species. It is a natural product of phenylpropanoid metabolism. Decarboxylation of transcinnamic acid to benzoic acid and its subsequent 2-hydroxylation results to SA. It undergoes metabolism by conjugating with glucose to SA glucoside and an ester. SA has direct involvement in plant growth, thermogenesis, flower induction and uptake of ions. It affects ethylene biosynthesis, stomatal movement and also reverses the effects of ABA on leaf abscission. Enhancement of the level of chlorophyll and carotenoid pigments, photosynthetic rate and modifying the activity of some of the important enzymes are other roles assigned to SA. This chapter gives a comprehensive coverage to all the above aspects.