A desaturase-like protein from white spruce is a Δ9 desaturase

Gymnospermae seed lipids are characterized by a high degree of desaturation, most having a Δ9 double bond. By degenerate polymerase chain reaction (PCR) we have isolated a white spruce (Picea glauca) cDNA clone that encodes an amino acid sequence sharing a high degree of homology with other putative plant acyl-coenzyme A (CoA) Des9 desaturases. Both in vivo and in vitro expression studies in a Δ9 desaturase-deficient yeast strain demonstrated the desaturation functionality of the white spruce clone, and gas chromatography-mass spectrometry (GC-MS) analyses confirmed the regioselectivity of the encoded enzyme. This is the first report of the functional characterization of a plant membrane-bound acyl-CoA-like protein Δ9 desaturase by heterologous expression in yeast. [Copyright &y& Elsevier]