Submitted to: Journal of Plant Physiology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/20/2009
Publication Date: 3/14/2009
Citation: Dierking, E., Bilyeu, K.D. 2009. Raffinose and Stachyose Metabolism are not Required for Efficient Soybean Seed Germination. Journal of Plant Physiology. 166(12):1329-1335. Interpretive Summary: Altering the composition of soybean seeds is an important goal for improving the nutritional components of food and feed developed from this important commodity. However, some desired seed composition changes have the potential to negatively impact the performance characteristics of the crop. The objective of this work was to evaluate the impact on seed germination for seeds with reductions in compounds that are anti-nutritional in animal feeds but normally produced and thought to be important for seed development. The results of this research demonstrated that seed germination is actually robust in lines that have altered seed composition and thus would produce a soybean meal with enhanced nutritional value for animal feeds. In addition, the results provide new information concerning the process of seed development and the necessity of producing the compounds.
Technical Abstract: Raffinose family oligosaccharides (RFOs), which include raffinose and stachyose, are thought to be an important source of energy during seed germination. In contrast to their potential for promoting germination, RFOs represent anti-nutritional units for monogastric animals when consumed as a component of feed. The exact role for raffinose and stachyose during soybean seed development and germination has not been determined. Previously, inhibition of RFO breakdown during imbibition and germination was shown to significantly delay germination in pea seeds. The objective of this study was to compare the germination potential for soybean seeds with either wild-type or low RFO levels and to examine the role of RFO breakdown in germination of those soybean seeds. There was no significant difference in germination between normal and low RFO soybean seeds when imbibed/germinated in water. Similar to the situation in pea, soybean seeds of wild-type carbohydrate composition experienced a delay in germination when treated with a chemical inhibitor of alpha-galactosidase activity (DGJ) during imbibition. However, low RFO soybean seed germination was not significantly delayed when treated with DGJ. In contrast to the situation in pea, the inhibitor-induced germination delay in wild-type soybean seeds was not partially overcome by the addition of galactose or sucrose. We conclude that a reduction in RFOs in soybean seeds does not correlate to a reduction or delay in germination.