Substrate Preference and Function of Salicylic Acid Methyltransferase in Dicots
Abstract
Salicylic acid carboxyl methyltransferase (SAMT) and
benzoic acid carboxyl methyltransferase (BAMT) are
enzymes in plants which catalyze the methylation of
salicylic acid (SA) and benzoic acid (BA).
These chemicals play an important role in in plant
defense against abiotic and biotic stress (SA and MeS),
herbivory (BA and MeB, SA and MeS) and pathogen
attack (SA and MeS), and are important for pollinator
attraction (BA and MeB).
´ SAMT: SSYSLMWLS versus SSYSLQWLS.
´ BAMT: SSYSLHWLS
SAMT evolved from a duplication event and a
following mutation in the active site of an ancestral
BAMT protein, and has since preferred catalyzing SA to
methyl salicylate (MeS) over BA to methyl benzoate
(MeB). The functionality of SAMT was found to have
been maintained in all previously studied dicots.