Involved in auxin biosynthesis. Belongs to the set of redundant YUCCA genes probably responsible for auxin biosynthesis in roots. H(+) + indole-3-pyruvate + NADPH + O2 = (indol-3-yl)acetate + CO2 + H2O + NADP(+) Plant hormone metabolism; auxin biosynthesis. Predominantly expressed in roots and young vegetative tissues, while it was under detectable levels in reproductive tissues, such as inflorescence stems, pedicels, and floral buds. Belongs to the FMO family.