Functional analysis of Flavonoid 3′,5′-hydroxylase from Tea plant (Camellia sinensis): critical role in the accumulation of catechins

BMC Plant Biology

Research Article

Oliver Yu¹  Tao Xia²  Xiu-Juan He²  Xiao-Lan Jiang²  Yun-Sheng Wang³  Ya-Jun Liu³  Yu-Jiao Xu⁴  Li-Ping Gao⁴  Xin-Zhen Wang⁴ 

[1] Conagen Inc, 15 DeAngelo Dr, 01730, Bedford, MA, USA;Wuxi NewWay, 401 Xing Yuan Bei Road, Wuxi, Jiangsu, China;Key Laboratory of Tea Biochemistry and Biotechnology, Ministry of Education in China, Anhui Agricultural University, Hefei, Anhui, China;Key Laboratory of Tea Biochemistry and Biotechnology, Ministry of Education in China, Anhui Agricultural University, Hefei, Anhui, China;School of Life Science, Anhui Agricultural University, Hefei, Anhui, China;School of Life Science, Anhui Agricultural University, Hefei, Anhui, China;

关键词: Camellia sinensis;    Flavonoid 3′5′-hydroxylase;    Functional analysis;    Heterologous expression;    Catechins;   

DOI  :  10.1186/s12870-014-0347-7

 received in 2014-05-16, accepted in 2014-11-24,  发布年份 2014

来源: Springer

【 摘 要 】

BackgroundFlavonoid 3′,5′-hydroxylase (F3′5′H), an important branch point enzyme in tea plant flavan-3-ol synthesis, belongs to the CYP75A subfamily and catalyzes the conversion of flavones, flavanones, dihydroflavonols and flavonols into 3′,4′,5′-hydroxylated derivatives. However, whether B-ring hydroxylation occurs at the level of flavanones and/or dihydroflavonols, in vivo remains unknown.ResultsThe Camellia sinensis F3′5′H (CsF3′5′H) gene was isolated from tea cDNA library. Expression pattern analysis revealed that CsF3′5′H expression was tissue specific, very high in the buds and extremely low in the roots. CsF3′5′H expression was enhanced by light and sucrose. Over-expression of CsF3′5′H produced new-delphinidin derivatives, and increased the cyanidin derivative content of corollas of transgenic tobacco plants, resulting in the deeper transgenic plant flower color. Heterologous expressions of CsF3′5′H in yeast were carried out to demonstrate the function of CsF3′5′H enzyme in vitro. Heterologous expression of the modified CsF3′5′H (CsF3′5′H gene fused with Vitis vinifera signal peptide, FSI) revealed that 4′-hydroxylated flavanone (naringenin, N) is the optimum substrate for CsF3′5′H, and was efficiently converted into both 3′4′- and 3′4′5′-forms. The ratio of 3′4′5′- to 3′4′-hydroxylated products in FSI transgenic cells was significantly higher than VvF3′5′H cells.ConclusionsCsF3′5′H is a key controller of tri-hydroxyl flavan-3-ol synthesis in tea plants, which can effectively convert 4′-hydroxylated flavanone into 3′4′5′- and/or 3′4′-hydroxylated products. These findings provide animportant basis for further studies of flavonoid biosynthesis in tea plants. Such studies would help accelerate flavonoid metabolic engineering in order to increase B-ring tri-hydroxyl product yields.

【 授权许可】

Unknown   
© Wang et al.; licensee BioMed Central Ltd. 2014. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.