Cloning and functional characterization of two cDNAs encoding NADPH-dependent 3-ketoacyl-CoA reductased from developing cotton fibers

Cell Res. 2005 Jun;15(6):465-73. doi: 10.1038/


Genes encoding enzymes involved in biosynthesis of very long chain fatty acids were significantly up-regulated during early cotton fiber development. Two cDNAs, GhKCR1 and GhKCR2 encoding putative cotton 3-ketoacyl-CoA reductases that catalyze the second step in fatty acid elongation, were isolated from developing cotton fibers. GhKCR1 and 2 contain open reading frames of 963 bp and 924 bp encoding proteins of 320 and 307 amino acid residues, respectively. Quantatitive RT-PCR analysis showed that both these genes were highly preferentially expressed during the cotton fiber elongation period with much lower levels recovered from roots, stems and leaves. GhKCR1 and 2 showed 30%-32% identity to Saccharomyces cerevisiae Ybr159p at the deduced amino acid level. These cotton cDNAs were cloned and expressed in yeast haploid ybr159wD mutant that was deficient in 3-ketoacyl-CoA reductase activity. Wild-type growth rate was restored in ybr159wD cells that expressed either GhKCR1 or 2. Further analysis showed that GhKCR1 and 2 were co-sedimented within the membranous pellet fraction after high-speed centrifugation, similar to the yeast endoplasmic reticulum marker ScKar2p. Both GhKCR(s) showed NADPH-dependent 3-ketoacyl-CoA reductase activity in an in vitro assay system using palmitoyl-CoA and malonyl-CoA as substrates. Our results suggest that GhKCR1 and 2 are functional orthologues of ScYbr159p.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3-Hydroxyacyl CoA Dehydrogenases / genetics*
  • Amino Acid Sequence
  • Cloning, Molecular
  • Cotton Fiber*
  • DNA, Complementary / genetics*
  • Endoplasmic Reticulum / enzymology
  • Gossypium / enzymology*
  • Molecular Sequence Data
  • NADP / metabolism
  • Saccharomyces cerevisiae / enzymology
  • Sequence Alignment


  • DNA, Complementary
  • NADP
  • 3-Hydroxyacyl CoA Dehydrogenases