The root-specific glutamate decarboxylase (GAD1) is essential for sustaining GABA levels in Arabidopsis

Nicolas Bouché, Aaron Fait, Moriyah Zik, Hillel Fromm

Research output: Contribution to journalArticlepeer-review

111 Scopus citations

Abstract

In plants, as in most eukaryotes, glutamate decarboxylase catalyses the synthesis of GABA. The Arabidopsis genome contains five glutamate decarboxylase genes and one of these genes (glutamate decarboxylase1; i.e. GAD1) is expressed specifically in roots. By isolating and analyzing three gad1 T-DNA insertion alleles, derived from two ecotypes, we investigated the potential role of GAD1 in GABA production. We also analyzed a promoter region of the GAD1 gene and show that it confers root-specific expression when fused to reporter genes. Phenotypic analysis of the gad1 insertion mutants revealed that GABA levels in roots were drastically reduced compared with those in the wild type. The roots of the wild type contained about sevenfold more GABA than roots of the mutants. Disruption of the GAD1 gene also prevented the accumulation of GABA in roots in response to heat stress. Our results show that the root-specific calcium/ calmodulin-regulated GAD1 plays a major role in GABA synthesis in plants under normal growth conditions and in response to stress.

Original languageEnglish
Pages (from-to)315-325
Number of pages11
JournalPlant Molecular Biology
Volume55
Issue number3
DOIs
StatePublished - 1 Dec 2004
Externally publishedYes

Keywords

  • Arabidopsis
  • Glutamate decarboxylase
  • Heat stress
  • Roots
  • T-DNA insertion mutant
  • γ-aminobtyrate

ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Genetics
  • Plant Science

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