Identification and functional characterization of a flax UDP-glycosyltransferase glucosylating secoisolariciresinol (SECO) into secoisolariciresinol monoglucoside (SMG) and diglucoside (SDG)

BMC Plant Biology

Research Article

Sylvie J Cloutier¹  Jason McCallum²  Chris W Kirby²  Bourlaye Fofana²  Kaushik Ghose³  Kumarakurubaran Selvaraj³  Michael Deyholos⁴  Marva Sweeney-Nixon⁵  Raju Datla⁶ 

[1] Cereal Research Centre, Agriculture and Agri-Food Canada, 195 Dafoe Road, R3T 2 M9, Winnipeg, MB, Canada;Crops and Livestock Research Centre, Agriculture and Agri-Food Canada, 440 University Avenue, C1A 4 N6, Charlottetown, PE, Canada;Crops and Livestock Research Centre, Agriculture and Agri-Food Canada, 440 University Avenue, C1A 4 N6, Charlottetown, PE, Canada;Department of Biology, University of Prince Edward Island, 550 University Avenue, C1A 4P3, Charlottetown, PE, Canada;Department of Biological Sciences, University of Alberta, T6G 2E9, Edmonton, AB, Canada;Department of Biology, University of Prince Edward Island, 550 University Avenue, C1A 4P3, Charlottetown, PE, Canada;National Research Council, 110 Gymnasium Place, S7N 0 W9, Saskatoon, SK, Canada;

关键词: Flax;    Lignan;    UGTs;    SDG;    Secoisolariciresinol;    Glucosylation;    Glycosyltranferases;   

DOI  :  10.1186/1471-2229-14-82

 received in 2013-08-04, accepted in 2014-03-19,  发布年份 2014

来源: Springer

【 摘 要 】

BackgroundLignans are a class of diphenolic nonsteroidal phytoestrogens often found glycosylated in planta. Flax seeds are a rich source of secoisolariciresinol diglucoside (SDG) lignans. Glycosylation is a process by which a glycosyl group is covalently attached to an aglycone substrate and is catalyzed by uridine diphosphate glycosyltransferases (UGTs). Until now, very little information was available on UGT genes that may play a role in flax SDG biosynthesis. Here we report on the identification, structural and functional characterization of 5 putative UGTs potentially involved in secoisolariciresinol (SECO) glucosylation in flax.ResultsFive UGT genes belonging to the glycosyltransferases’ family 1 (EC 2.4.x.y) were cloned and characterized. They fall under four UGT families corresponding to five sub-families referred to as UGT74S1, UGT74T1, UGT89B3, UGT94H1, UGT712B1 that all display the characteristic plant secondary product glycosyltransferase (PSPG) conserved motif. However, diversity was observed within this 44 amino acid sequence, especially in the two peptide sequences WAPQV and HCGWNS known to play a key role in the recognition and binding of diverse aglycone substrates and in the sugar donor specificity. In developing flax seeds, UGT74S1 and UGT94H1 showed a coordinated gene expression with that of pinoresinol-lariciresinol reductase (PLR) and their gene expression patterns correlated with SDG biosynthesis. Enzyme assays of the five heterologously expressed UGTs identified UGT74S1 as the only one using SECO as substrate, forming SECO monoglucoside (SMG) and then SDG in a sequential manner.ConclusionWe have cloned and characterized five flax UGTs and provided evidence that UGT74S1 uses SECO as substrate to form SDG in vitro. This study allowed us to propose a model for the missing step in SDG lignan biosynthesis.

【 授权许可】

Unknown   
© Ghose 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/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.