Koja Eiki, Ohata Soichiro, Maruyama Yoshinori, Suzuki Hideyuki, Shimosaka Makoto, Taguchi Goro
a Department of Applied Biology, Faculty of Textile Science and Technology , Shinshu University , Ueda , Japan.
b Department of Research and Development , Kazusa DNA Research Institute , Kisarazu , Japan.
Biosci Biotechnol Biochem. 2018 Oct;82(10):1790-1802. doi: 10.1080/09168451.2018.1491286. Epub 2018 Jul 4.
Rutin, a 3-rutinosyl quercetin, is a representative flavonoid distributed in many plant species, and is highlighted for its therapeutic potential. In this study, we purified uridine diphosphate-rhamnose: quercetin 3-O-glucoside 6″-O-rhamnosyltransferase and isolated the corresponding cDNA (FeF3G6″RhaT) from seedlings of common buckwheat (Fagopyrum esculentum). The recombinant FeF3G6″RhaT enzyme expressed in Escherichia coli exhibited 6″-O-rhamnosylation activity against flavonol 3-O-glucoside and flavonol 3-O-galactoside as substrates, but showed only faint activity against flavonoid 7-O-glucosides. Tobacco cells expressing FeF3G6″RhaT converted the administered quercetin into rutin, suggesting that FeF3G6″RhaT can function as a rhamnosyltransferase in planta. Quantitative PCR analysis on several organs of common buckwheat revealed that accumulation of FeF3G6″RhaT began during the early developmental stages of rutin-accumulating organs, such as flowers, leaves, and cotyledons. These results suggest that FeF3G6″RhaT is involved in rutin biosynthesis in common buckwheat.
芦丁，一种3 - 芸香糖基槲皮素，是一种分布于多种植物中的代表性黄酮类化合物，因其治疗潜力而备受关注。在本研究中，我们纯化了尿苷二磷酸 - 鼠李糖：槲皮素3 - O - 葡萄糖苷6″ - O - 鼠李糖基转移酶，并从普通荞麦（苦荞麦）幼苗中分离出相应的cDNA（FeF3G6″RhaT）。在大肠杆菌中表达的重组FeF3G6″RhaT酶以黄酮醇3 - O - 葡萄糖苷和黄酮醇3 - O - 半乳糖苷为底物表现出6″ - O - 鼠李糖基化活性，但对黄酮类7 - O - 葡萄糖苷仅表现出微弱活性。表达FeF3G6″RhaT的烟草细胞将施用的槲皮素转化为芦丁，这表明FeF3G6″RhaT在植物中可作为鼠李糖基转移酶发挥作用。对普通荞麦多个器官的定量PCR分析表明，FeF3G6″RhaT的积累在芦丁积累器官如花、叶和子叶的早期发育阶段就开始了。这些结果表明FeF3G6″RhaT参与普通荞麦中芦丁的生物合成。
