The discovery of compositional variation for the raffinose family of oligosaccharides in pea seeds

The raffinose family of oligosaccharides (RFO) is present in relatively high levels in grain legume seeds. They are considered to be antinutritional compounds because they are, at least in part, believed to be responsible for causing flatulence in humans, which is the single most important factor in deterring people from including more legume seeds in their diet. The RFO also have important functions within the plant. They serve as transport metabolites in many legumes and have been proposed to play a positive role in cold acclimatisation and in conferring desiccation tolerance during seed maturation. These responses to environmental stresses are believed to result from the RFO acting as protecting agents for membrane bound-proteins. We have screened 70 pea lines from the test array of the John Innes Pisum germplasm collection, and lines were selected which had unusual RFO composition. The soluble sugars within these lines were quantified using High Performance Anion Exchange Chromatography with Pulsed Amperometric Detection (HPAEC-PAD), and variants were identified which were deficient in verbascose and one with a reduced level of raffinose. These selected lines are being used in a crossing programme designed to study the genetics of the RFO pathway and to produce new material to test the effect of specific RFO on the plant's responses to the environment and on the diets of humans and animals.