Involved in auxin biosynthesis. Converts the indole-3-pyruvic acid (IPA) produced by the TAA family to indole-3-acetic acid (IAA). Unable to use tryptamine (TAM) as substrate. 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 anthers and in the apical gynoecium. Up-regulated by glucose. Down-regulated by heat stress. Positively regulated by LEC2 and by NGA3. Negatively regulated by SPL. No visible phenotype, due to the redundancy with the other members of the YUCCA family. Belongs to the FMO family.