Cloning of Myrosinase cDNA from Wasabia japonica Matsum.

Myrosinase (β-thioglucoside glucohydrolase, EC 3.2.3.1) is involved in pungency generation in wasabi (Wasabia japonica Matsum.). We isolated full-length cDNA (WjMY1) encoding myrosinase from the petiole of wasabi. The deduced polypeptide has 545 amino acids with a molecular weight of 62107. WjMY1 mRNA is accumulated in whole organs of the wasabi plant ; the order of expression is petiole≥rhizome>leaf. The order was found to be similar to that of the specific activity of myrosinase. This is the first report de- scribing the isolation of a myrosinase gene from wasabi.