. "Although auxin is known to regulate many processes in plant development and has been studied for over a century, the mechanisms whereby plants produce it have remained elusive. Here we report the characterization of a dominant Arabidopsis mutant, yucca, which contains elevated levels of free auxin. YUCCA encodes a flavin monooxygenase-like enzyme and belongs to a family that includes at least nine other homologous Arabidopsis genes, a subset of which appears to have redundant functions. Results from tryptophan analog feeding experiments and biochemical assays indicate that YUCCA catalyzes hydroxylation of the amino group of tryptamine, a rate-limiting step in tryptophan-dependent auxin biosynthesis." . . "Science" . "Cohen J.D." . "Fankhauser C." . "Zhao Y." . "Weigel D." . "Cashman J.R." . "Chory J." . "Christensen S.K." . "2001"^^ . "306-309" . "A role for flavin monooxygenase-like enzymes in auxin biosynthesis." . "291" . "doi:10.1126/science.291.5502.306" .