[Identification of Mortieralla isabellina M6-22 delta 6-fatty acid desaturase by heterologous expression in Saccharomyces cerevisiae].

Using plasmid pTMICL6 containing delta 6-fatty-acid desaturase gene from Mortieralla isabellina M6-22 as a template, 1.38 kb DNA fragment was amplified by PCR. The fragment was subcloned into the yeast-E. coli shuttle vector pYES2.0, then an expression recombinant plamid pYMID6 containing target gene was constructed. The pYMID6 was transformed into Saccharomyces cerevisiae for expression by LiAc method. It was found to exhibit delta 6-fatty acid desaturase activity in the recombinant S. cerevisiae YMID6 in the presence of exogenous fatty acid substrate linoleic acid under introduction of GAL. Expression of the delta 6-fatty acid desaturase gene under appropriate media and temperature conditions led to the production of gamma-linolenic acid reached 8.69% of the total yeast fatty acid by GC-MS detection. It is the first report about expression of M. isabellina D6D gene in S. cerevisiae.