Cloning and characterization of the abscisic acid-specific glucosyltransferase gene from adzuki bean seedlings

Plant Physiol. 2002 Jul;129(3):1285-95. doi: 10.1104/pp.001784.


The glycosylated forms of abscisic acid (ABA) have been identified from many plant species and are known to be the forms of ABA-catabolism, although their (physiological) roles have not yet been elucidated. ABA-glucosyltransferase (-GTase) is thought to play a key role in the glycosylation of ABA. We isolated an ABA-inducible GTase gene from UDP-GTase homologs obtained from adzuki bean (Vigna angularis) seedlings. The deduced amino acid sequence (accession no. AB065190) showed 30% to 44% identity with the known UDP-GTase homologs. The recombinant protein with a glutathione S-transferase-tag was expressed in Escherichia coli and showed enzymatic activity in an ABA-specific manner. The enzymatic activity was detected over a wide pH range from 5.0 to 9.0, the optimum range being between pH 6.0 and 7.3, in a citrate and Tris-HCl buffer. The product from racemic ABA and UDP-D-glucose was identified to be ABA-GE by gas chromatography/mass spectrometry. The recombinant GTase (rAOG) converted 2-trans-(+)-ABA better than (+)-S-ABA and (-)-R-ABA. Although trans-cinnamic acid was slightly converted to its conjugate by the GTase, (-)-PA was not at all. The mRNA level was increased by ABA application or by water stress and wounding. We suggest that the gene encodes an ABA-specific GTase and that its expression is regulated by environmental stress.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abscisic Acid / metabolism*
  • Abscisic Acid / pharmacology
  • Amino Acid Sequence
  • Base Sequence
  • Blotting, Northern
  • Blotting, Southern
  • Cloning, Molecular
  • DNA, Complementary / chemistry
  • DNA, Complementary / genetics
  • Escherichia coli / genetics
  • Fabaceae / drug effects
  • Fabaceae / enzymology
  • Fabaceae / genetics*
  • Gene Expression Regulation, Enzymologic / drug effects
  • Gene Expression Regulation, Plant / drug effects
  • Glucosyltransferases / genetics*
  • Glucosyltransferases / metabolism
  • Hydrogen-Ion Concentration
  • Hypocotyl / enzymology
  • Molecular Sequence Data
  • Plant Growth Regulators / metabolism*
  • Plant Growth Regulators / pharmacology
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Sequence Analysis, DNA
  • Substrate Specificity
  • Tritium
  • Uridine Diphosphate Glucose / pharmacology


  • DNA, Complementary
  • Plant Growth Regulators
  • Recombinant Fusion Proteins
  • Tritium
  • Abscisic Acid
  • Glucosyltransferases
  • Uridine Diphosphate Glucose

Associated data

  • GENBANK/AB065190