Involved in auxin biosynthesis. Both isoforms are catalitically active. Involved during embryogenesis and seedling development. Required for the formation of floral organs and vascular tissues. Belongs to the set of redundant YUCCA genes probably responsible for auxin biosynthesis in shoots. H(+) + indole-3-pyruvate + NADPH + O2 = (indol-3-yl)acetate + CO2 + H2O + NADP(+) Plant hormone metabolism; auxin biosynthesis. Expressed in leaves, stems, flowers, buds and siliques. Detected in the apical gynoecium and in the developing ovules. Expression relatively broad during early stages of embryogenesis and more restricted to apical region of the cotyledons in the mature embryo. Positively regulated by LEC2, by NGA3 and by STY1. No visible phenotype, due to the redundancy with the other members of the YUCCA family. May be due to an intron retention. Expressed only in flowers. Contains a transmembrane at positions 334 - 354. Belongs to the FMO family.