A stearoyl-CoA-specific Δ9 fatty acid desaturase from the basidiomycete Lentinula edodes

Abstract

A gene encoding a Δ9 fatty acid desaturase (Δ9-desaturase) was isolated from L. edodes. The open reading frame of this gene (named Le-FAD1) consisted of 1416 bp. The predicted protein of 471 amino acids shares 47-57% sequence identity with Δ9-desalurases from other fungi. Expression of the Le-FAD1 ORF complemented genetic disruption of the Saccharomyces cerevisiae OLE1 gene (Sc-OLE1). Fatty acid analysis of the Le-FAD1-expressing S. cerevisiae ole1-disrupted strain showed that Le-FAD1 protein had slight activity with palmitic acid (16:0) as the substrate and high activity with stearic acid (18:0). Analysis of transcriptional expression showed that the levels of Le-FAD1 mRNA in the primordium and fruiting body of L. edodes were higher than in mycelia cultivated at 18°C as well as 25°C. These results correlated with the increase of unsaturated fatty acids (UFAs) in total lipids during fruiting-body formation.