A mutation in protein phosphatase 2A regulatory subunit A affects auxin transport in Arabidopsis

• Published in: The EMBO journal Vol. 15; no. 9; pp. 2115 - 2124
• Main Authors: Garbers, C., DeLong, A., Deruere, J., Bernasconi, P., Soll, D., Evans, M. L.
• Format: Journal Article
• Language: English
• Published: Legacy CDMS 01-05-1996
• Subjects: Amino Acid Sequence; Arabidopsis - enzymology; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis thaliana; Base Sequence; Biological Transport; Cloning, Molecular; DNA, Complementary; Indoleacetic Acids - metabolism; Life Sciences (General); Molecular Sequence Data; Mutation; Phenotype; Phosphoprotein Phosphatases - genetics; Phosphoprotein Phosphatases - metabolism; Plant Proteins - genetics; Plant Proteins - metabolism; Protein Phosphatase 2; Regulatory Sequences, Nucleic Acid; Saccharomyces cerevisiae - enzymology; Saccharomyces cerevisiae - genetics; Space life sciences; Nasa Discipline Plant Biology; Non-Nasa Center; Nasa Discipline Number 93-10; Nasa Program Nscort; NASA Program NSCORT; NASA Discipline Number 93-10; NASA Discipline Plant Biology; Non-NASA Center
• ISSN: 0261-4189; 1460-2075
• DOI: 10.1002/j.1460-2075.1996.tb00565.x

The phytohormone auxin controls processes such as cell elongation, root hair development and root branching. Tropisms, growth curvatures triggered by gravity, light and touch, are also auxin-mediated responses. Auxin is synthesized in the shoot apex and transported through the stem, but the molecular mechanism of auxin transport is not well understood. Naphthylphthalamic acid (NPA) and other inhibitors of auxin transport block tropic curvature responses and inhibit root and shoot elongation. We have isolated a novel Arabidopsis thaliana mutant designated roots curl in NPA (rcn1). Mutant seedlings exhibit altered responses to NPA in root curling and hypocotyl elongation. Auxin efflux in mutant seedlings displays increased sensitivity to NPA. The rcn1 mutation was transferred-DNA (T-DNA) tagged and sequences flanking the T-DNA insert were cloned. Analysis of the RCN1 cDNA reveals that the T-DNA insertion disrupts a gene for the regulatory A subunit of protein phosphatase 2A (PP2A-A). The RCN1 gene rescues the rcn1 mutant phenotype and also complements the temperature-sensitive phenotype of the Saccharomyces cerevisiae PP2A-A mutation, tpd3-1. These data implicate protein phosphatase 2A in the regulation of auxin transport in Arabidopsis.