Isoflavonoid accumulation in soybean roots infected with vesicular-arbuscular mycorrhizal fungi

TLDR: Roots ofsoybean (Glycine max cv) and Amsoy 71 were analysed for their contents of stress metabolites 4, 6 and 8 weeks after the plants had been inoculated with different vesicular-arbuscular (VA) endomycorrhizal fungi (Glomus mosseae or Glomus fasciculatus or a mixture of the two).

Abstract: Roots ofsoybean (Glycine max cv. Amsoy 71) were analysed for their contents of stress metabolites 4, 6 and 8 weeks after the plants had been inoculated with different vesicular-arbuscular (VA) endomycorrhizal fungi (Glomus mosseae or Glomus fasciculatus or a mixture of the two) or 2 and 4 days after treatment with CuSO4 (10−3 m). All these treatments increased the concentrations of three isoflavonoids: glyceollin I, coumestrol and diadzein. The concentration of the phytoalexin glyceollin was greater in mycorrhizal infected roots than in non-mycorrhizal roots, but the amounts present were always low (< 1·0 μg g−1 fresh weight). The amounts of coumestrol and daidzein found in mycorrhizal roots varied between 7 and 34 μg g−1 fresh weight. The results are discussed in relation to the reported reduction of soil-borne disease caused by VA endomycorrhizal infection of plants.