Functional analysis of the PpAOMT genes. A, Expression of PpAOMT1 and PpAOMT2 in E. coli. Lane 1, purified recombinant PpAOMT1 enzyme; lane 2, purified recombinant PpAOMT2 enzyme; lane 3, molecular mass marker proteins. B, HPLC-ESI-MS/MS analysis of the products catalyzed the PpAOMT enzymes. C, Transient expression of PpAOMT2 in N. benthamiana. mAU, Milliabsorbance units. [See online article for color version of this figure.]