Mutations in Arabidopsis thaliana genes involved in the tryptophan biosynthesis pathway affect root waving on tilted agar surfaces.
Arabidopsis thaliana roots grow in a wavy pattern upon a slanted surface. A novel mutation in the anthranilate synthase alpha 1 (ASA1) gene, named trp5-2wvc1, and mutations in the tryptophan synthase alpha and beta 1 genes (trp3-1 and trp2-1, respectively) confer a compressed root wave phenotype on tilted agar surfaces. When trp5-2wvc1 seedlings 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 of trp5-2wvc1, trp2-1 and trp3-1 seedlings 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, trp5-2wvc1 mutants 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.
Rutherford
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Laboratory of Genetics, University of Wisconsin-Madison 53706, USA.
Gallois
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Masson
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D000483:Alleles; D000878:Anthranilate Synthase / Q000235:genetics; D017360:Arabidopsis / Q000235:genetics* / Q000502:physiology; D001483:Base Sequence; D007209:Indole-3-Glycerol-Phosphate Synthase / Q000235:genetics; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000235:genetics; D009154:Mutation; D018517:Plant Roots / Q000235:genetics / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins; D014364:Tryptophan / Q000096:biosynthesis*
D009097:Multienzyme Complexes; D029701:Saccharomyces cerevisiae Proteins; D014364:Tryptophan; D007209:Indole-3-Glycerol-Phosphate Synthase; D000878:Anthranilate Synthase; C087439:TRP3 protein, S cerevisiae