Isoflavone accumulation and the metabolic gene expression in response to persistent UV-B irradiation in soybean sprouts. (15th January 2020) - Lim, You Jin
Highlights: Six of 12 isoflavones in soybean sprouts were increased by UV-B irradiation. Malonyl genistin did not increase in dark but did in the sprouts grown under UV-B. UV-B specific chalcone synthetic genes were GmCHS 6, 7, and 8. Most isoflavone metabolic genes were highly activated in response to UV-B 24–36 h. Abstract: This study investigated the effects of persistent ultraviolet B (UV-B) irradiation on isoflavone accumulation in soybean sprouts. Three malonyl isoflavones were increased by UV-B. Malonylgenistin specifically accumulated upon UV-B exposure, whereas the other isoflavones were significantly increased under both dark conditions and UV-B exposure. The results of isoflavone accumulation to UV-B irradiation time were observed as following: acetyl glycitin rapidly increased and then gradually decreased; malonyl daidzin and malonyl genistin were highly accumulated within an intermediate period; genistein and daidzin were gradually maximized; daidzin, glycitin, genistein, and malonyl glycitin did not increase; and glycitin, acetyl daidzin, and acetyl genistin exhibited trace amounts. Transcriptional analysis of isoflavonoid biosynthetic genes demonstrated that most metabolic genes were highly activated in response to UV-B 24 and UV-B 36 treatments. In particular, it was found that GmCHS6, GmCHS7, and GmCHS8 genes among the eight known genes encoding chalcone synthase were specifically related to UV-B response.