Plant Molecular Biology

, Volume 36, Issue 5, pp 755–765

A novel aromatic alcohol dehydrogenase in higher plants: molecular cloning and expression

  • Deborah Goffner
  • Jan Van Doorsselaere
  • Nabila Yahiaoui
  • Josef Samaj
  • Jacqueline Grima-Pettenati
  • Alain M. Boudet
Article

DOI: 10.1023/A:1005991932652

Cite this article as:
Goffner, D., Van Doorsselaere, J., Yahiaoui, N. et al. Plant Mol Biol (1998) 36: 755. doi:10.1023/A:1005991932652

Abstract

Cinnamyl alcohol dehydrogenase (CAD; EC 1.1.195) catalyses the conversion of p-hydroxy-cinnamaldehydes to the corresponding alcohols and is considered a key enzyme in lignin biosynthesis. In a previous study, an atypical form of CAD (CAD 1) was identified in Eucalyptus gunnii [12]. We report here the molecular cloning and characterization of the corresponding cDNA, CAD 1-5, which encodes this novel aromatic alcohol dehydrogenase. The identity of CAD 1-5 was unambiguously confirmed by sequence comparison of the cDNA with peptide sequences derived from purified CAD 1 protein and by functional expression of CAD 1 recombinant protein in Escherichia coli. Both native and recombinant CAD 1 exhibit high affinity towards lignin precursors including 4-coumaraldehyde and coniferaldehyde, but they do not accept sinapaldehyde. Moreover, recombinant CAD 1 can also utilize a wide range of aromatic substrates including unsubstituted and substituted benzaldehydes. The open reading frame of CAD 1-5 encodes a protein with a calculated molecular mass of 35790 Da and an isoelectric point of 8.1. Although sequence comparisons with proteins in databases revealed significant similarities with dihydroflavonol-4-reductases (DFR; EC 1.1.1.219) from a wide range of plant species, the most striking similarity was found with cinnamoyl-CoA reductase (CCR; EC 1.2.1.44), the enzyme which directly precedes CAD in the lignin biosynthetic pathway. RNA blot analysis and immunolocalization experiments indicated that CAD 1 is expressed in both lignified and unlignified tissues/cells. Based on the catalytic activity of CAD 1 in vitro and its localization in planta, CAD 1 may function as an ‘alternative’ enzyme in the lignin biosynthetic pathway. However, additional roles in phenolic metabolism are not excluded.

cinnamyl alcohol dehydrogenase Eucalyptus gunnii lignin 

Copyright information

© Kluwer Academic Publishers 1998

Authors and Affiliations

  • Deborah Goffner
    • 1
  • Jan Van Doorsselaere
    • 1
  • Nabila Yahiaoui
    • 1
  • Josef Samaj
    • 1
  • Jacqueline Grima-Pettenati
    • 1
  • Alain M. Boudet
    • 1
  1. 1.Signaux et Messages Cellulaires chez les Végétaux-UMR CNRS-UPS 5546, Centre de Physiologie et Biologie VégétalesUniversité Paul SabatierToulouse cedexFrance
  2. 2.Laboratorium voor Genetica, K.LGentBelgium

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