Auxin Biosynthesis: Are the Indole-3-Acetic Acid and Phenylacetic Acid Biosynthesis Pathways Mirror Images?  . Issue 2 (26th April 2016)

• Record Type: Journal Article
• Authors: Cook, Sam D.; Nichols, David S.; Smith, Jason; Chourey, Prem S.; McAdam, Erin L.; Quittenden, Laura; Ross, John J.
• Is Part Of: Plant physiology. Volume 171:Issue 2(2016)
• Page Start: 1230
• Page End: 1241
• Publication Date: 2016-04-26
• Subjects: Plant physiology -- Periodicals; Botany -- Periodicals; Periodicals; Electronic journals; 571.2
• DOI: 10.1104/pp.16.00454
• Languages: English
• ISSNs: 0032-0889

Abstract

Abstract : Phenylacetic acid biosynthesis appears to proceed similarly to that of indole-3-acetic acid, but the enzymes responsible for these pathways are not identical. Abstract: The biosynthesis of the main auxin in plants (indole-3-acetic acid [IAA ]) has been elucidated recently and is thought to involve the sequential conversion of Trp to indole-3-pyruvic acid to IAA . However, the pathway leading to a less well studied auxin, phenylacetic acid (PAA ), remains unclear. Here, we present evidence from metabolism experiments that PAA is synthesized from the amino acid Phe, via phenylpyruvate. In pea ( Pisum sativum ), the reverse reaction, phenylpyruvate to Phe, is also demonstrated. However, despite similarities between the pathways leading to IAA and PAA, evidence from mutants in pea and maize ( Zea mays ) indicate that IAA biosynthetic enzymes are not the main enzymes for PAA biosynthesis. Instead, we identified a putative aromatic aminotransferase ( PsArAT ) from pea that may function in the PAA synthesis pathway.