Regioselective 6-, 7-, 8-, 3′-, and 4′-O-methylations underlie the structural diversity of lipophilic flavones produced in the trichomes of sweet basil (Ocimum basilicum L.). The positions 6, 7, and 4′ are methylated by a recently described set of cation-independent enzymes. The roles of cation-dependent O-methyltransferases still require elucidation. Here, the basil trichome EST database was used to identify a Mg2+-dependent O- ...