title: Developmental and nutritional regulation of isoflavone secretion from soybean roots.
abstract: Isoflavones play important roles in plant-microbe interactions in rhizospheres. Soybean roots secrete daidzein and genistein to attract rhizobia. Despite the importance of isoflavones in plant-microbe interactions, little is known about the developmental and nutritional regulation of isoflavone secretion from soybean roots. In this study, soybeans were grown in hydroponic culture, and isoflavone contents in tissues, isoflavone secretion from the roots, and the expression of isoflavone conjugates hydrolyzing beta-glucosidase (ICHG) were investigated. Isoflavone contents did not show strong growth-dependent changes, while secretion of daidzein from the roots dramatically changed, with higher secretion during vegetative stages. Coordinately, the expression of ICHG also peaked at vegetative stages. Nitrogen deficiency resulted in 8- and 15-fold increases in secretion of daidzein and genistein, respectively, with no induction of ICHG. Taken together, these results suggest that large amounts of isoflavones were secreted during vegetative stages via the hydrolysis of (malonyl)glucosides with ICHG.
authors.affiliation: a Research Institute for Sustainable Humanosphere , Kyoto University , Uji , Japan.
authors.forename: Akifumi
authors.initials: A
authors.lastname: Sugiyama
authors.affiliation: a Research Institute for Sustainable Humanosphere , Kyoto University , Uji , Japan.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Yamazaki
authors.affiliation: a Research Institute for Sustainable Humanosphere , Kyoto University , Uji , Japan.
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Yamashita
authors.affiliation: b Department of Biomolecular Engineering , Graduate School of Engineering, Tohoku University , Aoba, Sendai , Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Takahashi
authors.affiliation: b Department of Biomolecular Engineering , Graduate School of Engineering, Tohoku University , Aoba, Sendai , Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Nakayama
authors.affiliation: a Research Institute for Sustainable Humanosphere , Kyoto University , Uji , Japan.
authors.forename: Kazufumi
authors.initials: K
authors.lastname: Yazaki
mesh_terms: D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D019833:Genistein / Q000378:metabolism*; D006131:Growth Inhibitors / Q000096:biosynthesis / Q000378:metabolism*; D006868:Hydrolysis; D018527:Hydroponics; D007529:Isoflavones / Q000096:biosynthesis / Q000378:metabolism*; D009584:Nitrogen / Q000172:deficiency / Q000494:pharmacology; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology; D012230:Rhizobiaceae / Q000502:physiology; D058441:Rhizosphere; D013025:Glycine max / Q000187:drug effects / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology; D013559:Symbiosis / Q000502:physiology; D001617:beta-Glucosidase / Q000235:genetics* / Q000378:metabolism
chemical_list: D006131:Growth Inhibitors; D007529:Isoflavones; D010940:Plant Proteins; C004742:daidzein; D019833:Genistein; D001617:beta-Glucosidase; D009584:Nitrogen
keywords: beta-glucosidase; isoflavone secretion; root exudates; soybean