Functional Analysis Of Glycine Max GmFAD3A By Heterologous Expression In Arachis Hypogaea L.

Essential fatty acids can not be synthesized in human being and vertebrates, and must be got from ingestion.α-linolenic acid, (ALA,C18:3^Δ9,12,15) is one of the fatty acids with very important functions,and it belong to the n-3 polyunsaturated fatty acids (PUFAs). ALA can become EPA, DHA and some other n-3 PUFAs through a series of desaturation and lengthening reactions.And LA ,another important essential fatty acids, belong to n-6 polyunsaturated fatty acids,.it can becomeγ-linolenic acid (GLA), arachidonic acid (AA) and some other n-6 PUFAs through a series of desaturation and lengthening reactions. The functions of n-3 and n-6 PUFAs are often contrary in many aspects. They assort and restrict with each other to accommodate life activities. So the meal balance of n-6/n-3PUFAs is very important. But in fact the ratio of n-6/n-3 PUFAs in people's meal is generally badly on the high side. n-6 PUFAs are relatively excessive, but n-3 PUFAs badly lack. This complexion will lead to increases of high thrombus, atheroma and cancer, and it also can aggravate inflammation. So the direction of lipid research should aim to decrease the ratio of n-6/n-3PUFAs, which will make oil healthy. In molecular biology the PUFAs research work aims to the synthesizing enzymes of PUFAs.Arachis hypogaea L.(peanut) is the fourth widest oil plants.To be the most important oil plant in our courtry ,its production is higher than all the other oil plants,and more than 50% of them is in use of the production of oil. In it's seed oil there contains 15%-43% LA, but no n-3 PUFAs. Seed oil of Glycine max(soybean) contains a high level of ALA. Bilyeu KD and his fellows have cloned three soybeanω-3FAD. In developing seeds, the expression of the GmFAD3A come to 60% of the housekeeping gene expression level while GmFAD3C is 0.2% and GmFAD3B expression was below the experimental detection limit. And they find GmFAD3A is the main contributor for ALA in soybean seed oil, the proffer level is three times high than that of GmFAD3C. And then they found that when GmFAD3A is totally mutanted,the content ofα-linolenic acid will reduce to 46g Kg^-1oil;and when GmFAD3C is tolally mutanted ,the result is 15 g Kg^-1oil. It is three times higher when GmFAD3A mutation than GmFAD3C. That is, the expression of GmFAD3A is 300 times higher than GmFAD3C.,but the contribution of it is only 3 times higher. We can deduce that the contribution of GmFAD3C and GmFAD3A is 100/1 when they are in the same expression quantity, so the action of GmFAD3C is much higher than GmFAD3A, and the molecule of GmFAD3C is more steady than GmFAD3A. In the seed of soybean ,the expression of GmFAD3A is much higher but the action of it is much lower, the reason of it is not clear. Plant over express a low action gene instead of express a high action gene, the mechanism of it should be research.To investigate the functions of soybeanω- 3FAD, the cDNA of and GmFAD3C was separately amplified by RT-PCR from soybean immature seeds, then cloned into the T vector pUCm-T to generate the vector pUGFAD3C, then connect it to the expression vector pROKⅡto generate the recombinant vector pROKⅡFAD3C, then transformed into Agrobacterium tumefaciens EHA105, by this way we transform peanut. We use radicel and cotyledon to be the explant, and finally found that cotyledon is better. We use Km to filter transgene peanut, use PCR and PCR southern to identify transgene peanut, finally we analyse the change of fatty acids in peanut by gas chromatography, we can prove the function of GmFAD3C, in the other hand, we can increase the content of n-3 PUFAs in peanut.