ABSTRACT
Gamma-linolenic acid (GLA, C18:3delta(6, 9, 12) is one of nutritionally important polyunsaturated fatty acids in human and animal diets. Vast majority oilseeds crops do not produce GLA. Delta6-fatty acid desaturase (D6D) is the rate-limiting enzyme, which catalyzes the conversion of linoleic acid (LA) and alpha-linolenic acid (ALA) to GLA and octadecatetraenoic acid (OTA). In this study, a delta6-fatty acid desaturase gene isolated from Mortierella isabellina was transformed into some soybean cultivars Jilin 35, Jilin 47, Suinong 10, Suinong 14 and Heinong 37 successfully by agrobacterium-mediated cotylendon node transformation system. The results of PCR analysis, Southern blotting and Northern blotting with transgenic plants indicated that target gene was integrated into transgenic soybean genome and expressed at the level of RNA. Meanwhile, total fatty acids were extracted from transgenic seeds and methyl-esterified. Analysis of gas chromatograph (GC) showed that a novel peak corresponding to the standard of GLA methyl ester was detected, the highest percentage of gamma-lenolenic acid to total fatty acids in transgenic seeds was 27. 067%, which indicated that Mortierella isabellina delta6-fatty acid desaturase gene was expressed in transgenic soybean. It is so far the first report on the expression of delta6-fatty acid desaturase gene in transgenic soybean in the world.
