Methyltransferase involved in the biosynthesis of methyl benzoate in response to stresses. Utilizes exclusively benzoic acid (BA) as substrate. benzoate + S-adenosyl-L-methionine = methyl benzoate + S-adenosyl-L-homocysteine Belongs to the methyltransferase superfamily. Type-7 methyltransferase family. SABATH subfamily.