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Fibres from flax overproducing ?-1,3-glucanase show increased accumulation of pectin and phenolics and thus higher antioxidant capacity.

ABSTRACT: Recently, in order to improve the resistance of flax plants to pathogen infection, transgenic flax that overproduces ?-1,3-glucanase was created. ?-1,3-glucanase is a PR protein that hydrolyses the ?-glucans, which are a major component of the cell wall in many groups of fungi. For this study, we used fourth-generation field-cultivated plants of the Fusarium -resistant transgenic line B14 to evaluate how overexpression of the ?-1,3-glucanase gene influences the quantity, quality and composition of flax fibres, which are the main product obtained from flax straw.Overproduction of ?-1,3-glucanase did not affect the quantity of the fibre obtained from the flax straw and did not significantly alter the essential mechanical characteristics of the retted fibres. However, changes in the contents of the major components of the cell wall (cellulose, hemicellulose, pectin and lignin) were revealed. Overexpression of the ?-1,3-glucanase gene resulted in higher cellulose, hemicellulose and pectin contents and a lower lignin content in the fibres. Increases in the uronic acid content in particular fractions (with the exception of the 1 M KOH-soluble fraction of hemicelluloses) and changes in the sugar composition of the cell wall were detected in the fibres of the transgenic flax when compared to the contents for the control plants. The callose content was lower in the fibres of the transgenic flax. Additionally, the analysis of phenolic compound contents in five fractions of the cell wall revealed important changes, which were reflected in the antioxidant potential of these fractions.Overexpression of the ?-1,3-glucanase gene has a significant influence on the biochemical composition of flax fibres. The constitutive overproduction of ?-1,3-glucanase causes a decrease in the callose content, and the resulting excess glucose serves as a substrate for the production of other polysaccharides. The monosaccharide excess redirects the phenolic compounds to bind with polysaccharides instead of to partake in lignin synthesis. The mechanical properties of the transgenic fibres are strengthened by their improved biochemical composition, and the increased antioxidant potential of the fibres supports the potential use of transgenic flax fibres for biomedical applications.

SUBMITTER: Wojtasik W

PROVIDER: S-EPMC3598203 | biostudies-literature | 2013 Feb

REPOSITORIES: biostudies-literature

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Fibres from flax overproducing β-1,3-glucanase show increased accumulation of pectin and phenolics and thus higher antioxidant capacity.

Wojtasik Wioleta W Kulma Anna A Dymińska Lucyna L Hanuza Jerzy J Żebrowski Jacek J Szopa Jan J

BMC biotechnology 20130209

<h4>Background</h4>Recently, in order to improve the resistance of flax plants to pathogen infection, transgenic flax that overproduces β-1,3-glucanase was created. β-1,3-glucanase is a PR protein that hydrolyses the β-glucans, which are a major component of the cell wall in many groups of fungi. For this study, we used fourth-generation field-cultivated plants of the Fusarium -resistant transgenic line B14 to evaluate how overexpression of the β-1,3-glucanase gene influences the quantity, quali ...[more]

PMID: 23394294

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Project description:BackgroundFlaxseed oil is characterized by high content of essential polyunsaturated fatty acids (PUFA) promoted as a human dietary supplement protecting against atherosclerosis. The disadvantage of the high PUFA content in flax oil is high susceptibility to oxidation, which can result in carcinogenic compound formation. Linola flax cultivar is characterized by high linoleic acid content in comparison to traditional flax cultivars rich in linolenic acid. The changes in fatty acid proportions increase oxidative stability of Linola oil and broaden its use as an edible oil for cooking. However one of investigated transgenic lines has high ALA content making it suitable as omega-3 source. Protection of PUFA oxidation is a critical factor in oil quality. The aim of this study was to investigate the impact of phenylpropanoid contents on the oil properties important during the whole technological process from seed storage to grinding and oil pressing, which may influence health benefits as well as shelf-life, and to establish guidelines for the selection of new cultivars.MethodsThe composition of oils was determined by chromatographic (GS-FID and LC-PDA-MS) methods. Antioxidant properties of secondary metabolites were analyzed by DPPH method. The stability of oils was investigated: a) during regular storage by measuring acid value peroxide value p-anisidine value malondialdehyde, conjugated dienes and trienes; b) by using accelerated rancidity tests by TBARS reaction; c) by thermoanalytical - differential scanning calorimetry (DSC).ResultsIn one approach, in order to increase oil stability, exogenous substances added are mainly lipid soluble antioxidants from the isoprenoid pathway, such as tocopherol and carotene. The other approach is based on transgenic plant generation that accumulates water soluble compounds. Increased accumulation of phenolic compounds in flax seeds was achieved by three different strategies that modify genes coding for enzymes from the phenylpropanoid pathway. The three types of transgenic flax had different phenylpropanoid profiles detected in oil, highly increasing its stability.ConclusionsWe found that hydrophilic phenylpropanoids more than lipophilic isoprenoid compounds determine oil stability however they can work synergistically. Among phenolics the caffeic acid was most effective in increasing oil stability.

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Dataset Information

Fibres from flax overproducing ?-1,3-glucanase show increased accumulation of pectin and phenolics and thus higher antioxidant capacity.

Publications

Fibres from flax overproducing β-1,3-glucanase show increased accumulation of pectin and phenolics and thus higher antioxidant capacity.

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