SEQUENCE OF A CDNA CLONE ENCODING THE ENZYME MYROSINASE AND EXPRESSION OF MYROSINASE IN DIFFERENT TISSUES OF BRASSICA-NAPUS

We have isolated and sequenced a cDNA clone for the glucosinolate-degrading enzyme myrosinase from Brassica napus (oilseed rape). Using a probe derived from the cDNA clone we have studied the expression of myrosinase genes in different tissues of B. napus. The myrosinase genes are most highly expressed in the young leaves, the cotyledons and the developing seed. Other parts of the plant only show a relatively low expression of myrosinase. In the developing seed the expression of myrosinase is first detected at 15 days after pollination and at the highest levels around 30 days after pollination. The myrosinase genes are turned on earlier, but also silenced earlier than the genes for the storage protein cruciferin.