S-adenosyl-L-methionine-dependent methyltransferase. Involved in glucosinolate metabolism and defense against phytopathogens. Highly reactive to thiocyanate (NCS(-)) derived from myrosinase-mediated hydrolysis of glucosinolates upon tissue damage. S-adenosyl-L-methionine + thiocyanate = methyl thiocyanate + S-adenosyl-L-homocysteine Expressed in shoots, leaves, stems, inflorescences, flowers and green siliques. No visible phenotype under normal growth conditions. Increased sensitivity to thiocyanate in medium and lower methyl halide emissions. Belongs to the class I-like SAM-binding methyltransferase superfamily. TPMT family.