Mutations inArabidopsis thalianagenes involved in the tryptophan biosynthesis pathway affect root waving on tilted agar surfaces
Arabidopsis thalianaroots grow in a wavy pattern upon a slanted surface. A novel mutation in theanthranilate synthase α1(ASA1) gene, namedtrp5–2wvc1, and mutations in thetryptophan synthase α and 1genes (trp3–1andtrp2–1, respectively) confer a compressed root wave phenotype on tilted agar surfaces. Whentrp5–2wvc1seedlings are grown on media supplemented with anthranilate metabolites, their roots wave like wild type. Genetic and pharmacological experiments argue that the compressed root wave phenotypes oftrp5–2wvc1,trp2–1andtrp3–1seedlings are not due to reduced IAA biosynthetic potential, but rather to a deficiency in L-tryptophan (L-Trp), or in a L-Trp derivative. Although the roots of 7-day-old seedlings possess higher concentrations of free L-Trp than the shoot as a whole,trp5–2wvc1mutants show no detectable alteration in L-Trp levels in either tissue type, suggesting that a very localized shortage of L-Trp, or of a L-Trp-derived compound, is responsible for the observed phenotype.
Document Type: Original Article
Affiliations: 1: Laboratory of Genetics, University of Wisconsin – Madison, 445 Henry Mall, Madison WI 53706, USA, and 2: Laboratoire de Physiologie et Biologie Moléculaire Végétales, CHRS UMR 5545 Université de Perpignan, F-66860 Perpignan Cedex, France
Publication date: October 1, 1998