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Abstract Detail



Genomics / Proteomics

Fofana, Bourlaye [1], Ghose, Kaushik [1], McCallum, Jason [1], You, Frank M. [2], Cloutier, Sylvie J. [3].

UGT74S1 Is a Single-Copy Gene and Is Unique In Controlling Secoisolariciresinol Diglucoside (SDG) Formation In Flax (Linum usitatissimum).

Flax secoisolariciresinol diglucoside (SDG) lignan is a natural glycosylated diphenolic phytoestrogen for which a positive role in human metabolic diseases is emerging. As part of the Genome Canada flax TUFGEN genomics project, UGT74S1 was identified and characterized as an enzyme sequentially glucosylating secoisolariciresinol (SECO) into secoisolariciresinol monoglucoside (SMG) and SDG when expressed in yeast. However, it remained unknown whether UGT74S1 was the only UGT achieving these glucosylation steps in flax. In this study, UGT74S1 gene duplication in the genome was investigated. Its closely related genes among the 299 UGTs present in the flax draft genome were identified and their gene expression as well as enzyme activity toward SECO, UDP-glucose and UDP-galactose were determined. There was no evidence of gene duplication for UGT74S1 which was found as a single gene on chromosome 7. Phylogenetic analysis identified four main clusters. Cluster 4 was the most diverse and included UGT74S1 forming a small gene family with six other UGTs, referred to as LuS10008742 (UGT74S2), LuS10006721 (UGT74S5), LuS10006351 (UGT74S5), LuS10024486 (UGT74S3), LuS10014148 (UGT74S4) and LuS10006353 (UGT74S3). The latter two were the most closely related to UGT74S1, appeared to be duplicated copies located on chromosomes 8 and 14, respectively. Heterologous expression of UGT74S1, LuS10014148 (UGT74S4) and LuS10006353 (UGT74S3) showed similar protein expression but LuS10014148 (UGT74S4) and LuS10006353 (UGT74S3) enzymes had seven times less glucosylation activity towards SECO and failed to produce SDG compared with UGT74S1. All three enzymes formed very low amount of SECO monogalactoside (SMGal) no SECO digalactoside (SDgal). The study confirmed our previous findings and suggests that UGT74S1 is unique in controlling SDG formation in flax, although a small contribution for SMG precursor may arise from its closely related members of the gene family.


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1 - Crops and Livestock Research Centre, Agriculture and Agri-Food Canada, 440 University Avenue, Charlottetown, PE, C1A 4N6, Canada
2 - Cereal Research Centre, Agriculture and Agri-Food Canada, 101 Route 100 Unit 100, Morden, MB, R6M 1Y5, Canada
3 - Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, ON, K1A 0C6, Canada

Keywords:
Flax
SDG
UGT74S1
gene family evolution
gene expression
Enzyme activity.

Presentation Type: Poster:Posters for Topics
Session: P
Location: Hall D/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 5:30 PM
Number: PGP002
Abstract ID:200
Candidate for Awards:None


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