Over-expression of α-galactosidase in pea seeds to reduce raffinose oligosaccharide contentThis paper is one of a selection of papers published in a Special Issue from the National Research Council of Canada – Plant Biotechnology Institute.

The raffinose family of oligosaccharides (RFO) is a series of complex carbohydrates stored in seeds of many plant families, especially in legumes. The digestive system of nonruminant animals, including that of humans, cannot break down all of the chemical bonds in these carbohydrates; therefore, catabolism is achieved anaerobically by intestinal flora. The resulting digestive problems reduce acceptance and limit the widespread consumption of these otherwise nutritious seeds. To demonstrate a solution to this problem, transgenic lines of pea (Pisum sativum L.) expressing the α-galactosidase gene from coffee (Coffea arabica L.) were developed. Plants with a single copy of the inserted gene were selected, and two of these lines showed significant reductions of up to 40% in oligosaccharide content (raffinose, stachyose). Quantitative RT-PCR confirmed the presence of the α-galactosidase RNA in both leaves and cotyledons. Sugars were analyzed using whole seeds or only a portion of a seed; in the latter case, ge...