De novo biosynthesis of C-arabinosylated flavones by utilization of indica rice C-glycosyltransferases

• Main Authors: Zhuo Chen, Yuwei Sun, Guangyi Wang, Ying Zhang, Qian Zhang, Yulian Zhang, Jianhua Li, Yong Wang
• Format: Article
• Language: English
• Published: SpringerOpen 2021-06-01
• Series: Bioresources and Bioprocessing
• Subjects: De novo biosynthesis; C-Arabinoside flavone; C-Glycosyltransferase; Rice
• Online Access: https://doi.org/10.1186/s40643-021-00404-3

Abstract Flavone C-arabinosides/xylosides are plant-originated glycoconjugates with various bioactivities. However, the potential utility of these molecules is hindered by their low abundance in nature. Engineering biosynthesis pathway in heterologous bacterial chassis provides a sustainable source of these C-glycosides. We previously reported bifunctional C-glucosyl/C-arabinosyltransferases in Oryza sativa japonica and O. sativa indica, which influence the C-glycoside spectrum in different rice varieties. In this study, we proved the C-arabinosyl-transferring activity of rice C-glycosyltransferases (CGTs) on the mono-C-glucoside substrate nothofagin, followed by taking advantage of specific CGTs and introducing heterologous UDP-pentose supply, to realize the production of eight different C-arabinosides/xylosides in recombinant E. coli. Fed-batch fermentation and precursor supplement maximized the titer of rice-originated C-arabinosides to 20–110 mg/L in an E. coli chassis. The optimized final titer of schaftoside and apigenin di-C-arabinoside reached 19.87 and 113.16 mg/L, respectively. We demonstrate here the success of de novo bio-production of C-arabinosylated and C-xylosylated flavones by heterologous pathway reconstitution. These results lay a foundation for further optimal manufacture of complex flavonoid compounds in microbial cell factories.