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The specificities of plant enzymes and their effects on the seed oil quality

Jeppsson, Simon (2020). The specificities of plant enzymes and their effects on the seed oil quality. Diss. (sammanfattning/summary) Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2020:24
ISBN 978-91-7760-566-9
eISBN 978-91-7760-567-6
[Doctoral thesis]

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Abstract

Triacylglycerols, glycerides with three fatty acids, are the chemical constituent of seed oils. The fatty acid composition determines the chemical and physical characteristics of an oil. Conventional vegetable oils contain a few reoccurring fatty acids, but plants can produce several hundreds of different fatty acids. A wide range of plant oils and their fatty acids with specific characteristics are suitable replacements for many fossil-oil based commodities. Plant breeders and researcher are thus, modifying the fatty acid composition in oil crops to enhance such properties. Erucic acid is a fatty acid, with extensive use within industrial applications. Fatty acids originate from the plastids in plants, but the assembly of triacylglycerols occurs in the endoplasmic reticulum, where integral membrane-bound acyltransferases catalyse the formation of triacylglycerols. Modifications of fatty acids occur while they are associated with specific lipid molecules. Different types of fatty acid modifications require association with different lipid molecules, and several unusual fatty acids require multiple sequential modifications. The intricate system of synthesis, modification and assembly thus requires channelling of fatty acids and substrates from different subcellular compartments and concurrent transfer of fatty acids from various lipid molecules, often at multiple occasions. The enzymes governing these processes often have very distinct substrate specificities, which we investigate here. Re-engineering of a seed oil’s fatty acid composition or the introduction of an exotic fatty acid is a complex process and must take into consideration plants endogenous enzymes, their substrate specificities and the available substrate pools. Detailed biochemical characterisations of crucial enzymes are thus essential for a successful outcome of such efforts. We have thoroughly investigated a range of acyltransferases and other enzymes involved in lipid metabolism, mainly focused towards erucic acid in several plant species, including Arabidopsis, Camelina sativa, Brassica napus, Crambe hispanica ssp. abyssinica and Tropaeolum majus. DGAT2 catalyses the acyl-CoA dependent formation of triacylglycerol and is thus one of the acyltransferases involved in oil synthesis. The assessed substrate specificities of several DGAT2 indicate that its substrate specificity is a bottleneck in the further increase of erucic acid. We have also investigated the amino acid sequence motifs governing the specificity towards erucic acid in DGAT2 enzymes.

Authors/Creators:Jeppsson, Simon
Title:The specificities of plant enzymes and their effects on the seed oil quality
Year of publishing :2020
Number:2020:24
Number of Pages:80
Publisher:Department of Plant Breeding, Swedish University of Agricultural Sciences
ISBN for printed version:978-91-7760-566-9
ISBN for electronic version:978-91-7760-567-6
ISSN:1652-6880
Language:English
Publication Type:Doctoral thesis
Article category:Other scientific
Version:Published version
Full Text Status:Public
Subjects:(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 404 Agricultural Biotechnology > Genetics and Breeding
Keywords:plant lipids, TAG, DGAT, acyltransferase, lipid synthesis, enzyme specificities, erucic acid, oil crop
URN:NBN:urn:nbn:se:slu:epsilon-p-105274
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-p-105274
ID Code:16926
Faculty:LTV - Fakulteten för landskapsarkitektur, trädgårds- och växtproduktionsvetenskap
Department:(LTJ, LTV) > Department of Plant Breeding (from 130101)
Deposited By: SLUpub Connector
Deposited On:24 Apr 2020 13:40
Metadata Last Modified:24 Apr 2020 13:40

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