2PE biosynthesis in flowers. The 2PE biosynthetic pathways are shown for petunia (1Kaminaga et al., 2006), rose (2Sakai et al., 2007; 3Hirata et al., 2012), and plumeria (this study). The 2PE biosynthetic pathway in plumeria flowers is highlighted in pink. Solid arrows indicate reactions previously reported, stacked arrows indicate the presence of multiple steps, and the dotted arrow suggests a nonenzymatic reaction. PPDC, Phenylpyruvic acid decarboxylase.