Plant Molecular Biology

, Volume 31, Issue 2, pp 323–335

Cloning, molecular and functional characterization of Arabidopsis thaliana allene oxide synthase (CYP 74), the first enzyme of the octadecanoid pathway to jasmonates

  • Dietmar Laudert
  • Utta Pfannschmidt
  • F. Lottspeich
  • Heike Holländer-Czytko
  • Elmar W. Weiler
Research Article

DOI: 10.1007/BF00021793

Cite this article as:
Laudert, D., Pfannschmidt, U., Lottspeich, F. et al. Plant Mol Biol (1996) 31: 323. doi:10.1007/BF00021793
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Abstract

Allene oxide synthase, an enzyme of the octadecanoid pathway to jasmonates, was cloned from Arabidopsis thaliana as a full-length cDNA encoding a polypeptide of 517 amino acids with a calculated molecular mass of 58705 Da. From the sequence, an N-terminal transit peptide of 21 amino acids resembling chloroplast transit peptides was deduced. Three out of four invariant amino acid residues of cytochrome P450 heme-binding domains are conserved and properly positioned in the enzyme coding region, including the heme-accepting cysteine (Cys-470). Southern analysis indicated in A. thaliana only one allene oxide synthase gene to be present. While transcript levels were rapidly and transiently induced after wounding of the leaves, allene oxide synthase activity remained nearly constant at a low level of ca. 0.8 nkat per mg of protein. The cDNA encoding A. thaliana allene oxide synthase was highly expressed in bacteria giving rise to a polypeptide of the calculated molecular mass. The protein was enzymatically active, and verification of the reaction products by GC-MS showed that it was capable of utilizing not only 13-hydroperoxylinolenic acid (13-hydroperoxy-9(Z), 11(E), 15(Z)-octadecatrienoic acid), but also 13-hydroperoxylinoleic acid (13-hydroperoxy-9(Z), 11(E)-octadecadienoic acid) as substrate. The data suggest parallel pathways to jasmonates from linolenic acid or linoleic acid in A. thalina.

Key words

Arabidopsis thalianaallene oxide synthaseCYP74octadecanoidsjasmonate biosynthesis12-oxo-phytodienoic acid

Copyright information

© Kluwer Academic Publishers 1996

Authors and Affiliations

  • Dietmar Laudert
    • 1
  • Utta Pfannschmidt
    • 1
  • F. Lottspeich
    • 2
  • Heike Holländer-Czytko
    • 1
  • Elmar W. Weiler
    • 1
  1. 1.Lehrstuhl für PflanzenphysiologieRuhr-Universität BochumBochumGermany
  2. 2.Abt. ProteinanalytikMax-Planck-Institut für BiochemieMartinsriedGermany