Removal of An Abundant Allergen From Soybean Seeds by RNA Interference (RNAi) Technology.

Soybeans are extensively used as a high-protein feed ingredient in livestock production. Because of its functional qualities and many health benefits, soy protein is widely used in a variety of food products.  However, it is becoming evident that soy proteins can cause allergic reactions in livestock and small percentage of sensitive individuals.  β-conglycinin, an abundant storage protein, is composed of α’- (76 kD), α- (72 kD), and β- (53 kD) subunits.  We have recently shown that some of these subunits may be potential food and feed allergens. Thus, the development of soybean cultivars lacking all three subunits of soybean could be a valuable source of hypoallergenic protein.  In order to lower the accumulation of β-conglycinin in soybean, we have designed constructs in which we cloned two copies of the target sequence in an inverted-repeat orientation to produce duplex RNA.  Using Agrobacterium-mediated transformation, we have introduced the RNAi construct into the soybean genome and have obtained several independent transgenic lines.  Western blot analysis using β-conglycinin antibodies revealed a drastic reduction and in some cases the complete absence of all three subunits in several transgenic soybean lines.  These transgenic soybeans lacking all three subunits of β-conglycinin could be a valuable source of hypoallergenic protein.