Chigen Tsukamoto

Group a acetyl saponin-deficient mutant from the wild soybean

Abstract Group A acetyl saponin deficient mutant was discovered from wild soybeans ( Glycine soja ). The mutant contained deacetyl Af but not deacetyl Ab. F 1 seeds were obtained from a cross between the mutant and a soybean variety which carries the acetylation activity of deacetyl Af but lacks the glucosylation activity for producing saponin Ab. The F 1 seeds contained saponin Ab but deacetyl Af was not detected. It can be seen that the mutant lacks the ability to acetylate the hydroxyl groups of the terminal sugar of the sugar chain attached at the C-22 position of soyasapogenol A, and that saponin Ab is produced via saponin Af, not via deacetyl Ab. The mutant carried additional mutations in the seed protein composition, such as a deficiency in the ′α subunit of β-conglycinin.