Construction of an RNAi plasmid targeting Mortierella isabellinaΔ12-fatty acid desaturase gene

Mortierella isabellina is an oil-producing fungal species which has been widely studied for producing polyunsaturated fatty acids including γ-Linolenic acid and arachidonic acid in China.Our previous research showed that Mortierella isabellina M6-22 is a hygromycin resistant fungal strain,and no auxotrophic mutant strains from M.isabellina were constructed so far,which limits its applications of genetic manipulation.In this study,DsRed gene which encodes a red-fluorescent protein was used as a report gene to construct a vector for both heterologous filamentous fungal gene and RNAi expression.The resultant vector pS-DsRED was further delivered into M.isabellina M6-22 by PEG/CaCl2-mediated protoplast transformation for expression,and acquired pink positive colonies.Based on the pS-DsRED,an RNAi expression plasmid pSREDMID12RNAi targeting Monierella isabellina delta-12-fatty acid desaturase gene was constructed,which provided a basis for the subsequent target gene knockdown and gene functional analysis.