Two new dammarane-type triterpenoid saponins, chikusetsusaponin LM1 (1), chikusetsusaponin LM2 (2), and three known triterpenoid saponins, ginsenoside Re (3), ginsenoside Rg1 (4), ginsenoside F3 (5), were isolated from the leaves of P. japonicus C. A. Meyer collected in Miyazaki prefecture, Japan. The structures of new chikusetsusaponins were elucidated on the basis of spectroscopic and physicochemical evidences.
AbstractGmMYB176 is an R1 MYB transcription factor that regulates multiple genes in the isoflavonoid biosynthetic pathway, thereby affecting their levels in soybean roots. While GmMYB176 is important for isoflavonoid synthesis, it is not sufficient for the function and requires additional cofactor(s). The aim of this study was to identify the GmMYB176 interactome for the regulation of isoflavonoid biosynthesis in soybean. Here, we demonstrate that a bZIP transcription factor GmbZIP5 co-immunoprecipitates with GmMYB176 and shows protein–protein interaction in planta. RNAi silencing of GmbZIP5 reduced the isoflavonoid level in soybean hairy roots. Furthermore, co-overexpression of GmMYB176 and GmbZIP5 enhanced the level of multiple isoflavonoid phytoallexins including glyceollin, isowighteone and a unique O-methylhydroxy isoflavone in soybean hairy roots. These findings could be utilized to develop biotechnological strategies to manipulate the metabolite levels either to enhance plant defense mechanisms or for human health benefits in soybean or other economically important crops.
New Triterpenoid Saponins from Leaves of Panax Japonicus (3). Saponins of the Specimens Collected in Miyazaki Prefecture