The Study Of Differentially Expressed Genes Influencing On ARA Synthesis In High Yield Mortierella Isabellina Strains

Arachidonic acid is a kind of unsaturated fatty acid and necessary for humanbody. It has a wide range of biological activity and important role in nutrition. Thetraditional preparation method costs more and is inefficient. Microorganismfermentation to producte arachidonic acid can reduce the cost and increaseproduction.Subtracted cDNA library of different arachidonic acid production inMortierella isabellina is structured by SSH. Differentially expressed genes of thiscDN library are screened and identified by reverse dot blot technology and get thedifferentially expressed genes△5、△6-fatty acid desaturation enzyme gene andunknown gene UG1.△5、△6-fatty acid desaturation enzyme genes are key enzymesto Arachidonic acid synthesis.It can clear the role of arachidonic acid biosynthesis ofthese differentially expressed genes to evaluate the relationship between thesedifferentially expressed genes and arachidonic acid production. The purpose of thisstudy is to construct RNA interference vectors for silencing differentially expressedgenes in high-yield ARA Mortierella isabellina strains and explore the relationshipbetween these differentially expressed gene expression and the production of ARA.Method:△5、△6-fatty acid desaturation enzyme genes RNAi vectors andUG1RNAi vector are contructed and transferred into high-yield ARA Mortierellaisabellina strains by PEG/CaCl2protoplast reforming process. The expression changesof purpose genes are detected by real time-PCR technology.The production of ARA isdetected by gas chromatographic technique.Results: This study successfully constructed△5、△6-fatty acid desaturationenzyme genes RNAi vectors and UG1RNAi vector and got Mortierella isabellinastrains transferred RNAi vectors. The results of real time-PCR show that it’ssuccessful in reducing the expression of purpose gene.Conclusions: The experimental Results show that mRNA expression of△5、△6-fatty acid desaturation enzyme genes and UG1are certain positive correlation withproduction of ARA. The mRNA expression quantity of△5-desaturation enzymegene has more obvious influence on the yield of ARA. The mRNA expression quantity of Unknown genes (UG1) has no obvious effect on yield of ARA.