Abstract:Abstract:[Objective] To study the relation between mRNA expression of △5-desaturase gene and arachidonic acid production. [Methods] Using fluorescence quantitative PCR, we determined the mRNA expression levels of △5-desaturase gene of five Mortierlla isabellina strains cultured for the same time and strain YZ-124 cultured for different time. Simultaneously, we measured the contents of arachidonic acid by gas chromatography. [Results] The results showed that △5-desaturase gene mRNA expression level of distinct strains was different. Expression level of the original strain As3.3410 was the lowest, whereas that of the mutant strain YZ-124 was the highest. The mRNA expression of △5-desaturases gene decreased gradually with fermentation time. [Conclusion] According to arachidonic acid yield, mRNA expression quantity of △5-desaturase gene presented a positive correlation with arachidonic acid content in cultured oil.