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Evidence that indole-3-acetic acid is not synthesized via the indole-3-acetamide pathway in pea roots
journal contributionposted on 2023-05-18, 02:42 authored by Quittenden, LJ, Erin McAdam, Noel DaviesNoel Davies, John RossJohn Ross
The biosynthetic route of the key plant hormone, indole-3-acetic acid (IAA) has confounded generations of biologists. Evidence in higher plants has implicated two auxin intermediates with roles established in bacteria: indole-3-acetamide (IAM) and indole-3-pyruvic acid. Herein, the IAM pathway is investigated in pea (Pisum sativum), a model legume. The compound was not detected in pea tissue, although evidence was obtained for its presence in Arabidopsis, tobacco, and maize. Deuterium-labeled tryptophan was not converted to IAM in pea roots, despite being converted to IAA. After feeds of deuterium-labeled IAM, label was recovered in the IAA conjugate IAA-aspartate (IAAsp), although there was little or no labeling of IAA itself. Plants treated with IAM did not exhibit high-IAA phenotypes, and did not accumulate IAA. This evidence, taken together, indicates that although exogenous IAM may be converted to IAA (and further to IAAsp), the IAM pathway does not operate naturally in pea roots.
Publication titleJournal of Plant Growth Regulation
Department/SchoolSchool of Natural Sciences
Place of publication175 Fifth Ave, New York, USA, Ny, 10010
Rights statementCopyright 2014 Springer