Wheat arabinoxylans: Exploiting variation in amount and composition to develop enhanced varieties

Saulnier, Luc; Sado, Pierre-Etienne; Branlard, Gérard; Charmet, Gilles; Guillon, Fabienne

doi:10.1016/j.jcs.2007.06.014

Cited by 357 publications

(323 citation statements)

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“…By contrast, xylan synthase complexes partially deficient in TaGT47_2 can make such long chains, albeit at a much decreased rate. To our knowledge, this is the first finding of a clear difference between the roles of IRX9 and IRX10 homologs, and it is possible that they are only apparent in wheat endosperm WE-AX because of the much greater average chain length of 1,000 to 1,500 Xyl (Saulnier et al, 2007) compared with Arabidopsis stem GX at around 100 Xyl (Pena et al, 2007).…”

Section: We-ax Chain Lengthmentioning

confidence: 83%

“…Using a strong starchy endosperm-specific promoter to drive RNA interference (RNAi) to suppress specific transcripts, we have demonstrated the key role of TaCSLF6 in synthesizing 1,3;1,4-b-D-glucan (Nemeth et al, 2010) and that the GT61 gene TaXAT1 is responsible for nearly all the monosubstituted Ara in AX in endosperm (Anders et al, 2012). The amount and structure of AX in wheat starchy endosperm are also of great practical importance; as it is the main component of dietary fiber in wheat foods, it is a major contributor of dietary fiber in the human diet (Topping, 2007), and it also affects the processing properties of wheat flour for different end uses (Saulnier et al, 2007).…”

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confidence: 99%

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RNA Interference Suppression of Genes in Glycosyl Transferase Families 43 and 47 in Wheat Starchy Endosperm Causes Large Decreases in Arabinoxylan Content

et al. 2013

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The cell walls of wheat (Triticum aestivum) starchy endosperm are dominated by arabinoxylan (AX), accounting for 65% to 70% of the polysaccharide content. Genes within two glycosyl transferase (GT) families, GT43 (IRREGULAR XYLEM9 [IRX9] and IRX14) and GT47 (IRX10), have previously been shown to be involved in the synthesis of the xylan backbone in Arabidopsis, and close homologs of these have been implicated in the synthesis of xylan in other species. Here, homologs of IRX10 TaGT47_2 and IRX9 TaGT43_2, which are highly expressed in wheat starchy endosperm cells, were suppressed by RNA interference (RNAi) constructs driven by a starchy endosperm-specific promoter. The total amount of AX was decreased by 40% to 50% and the degree of arabinosylation was increased by 25% to 30% in transgenic lines carrying either of the transgenes. The cell walls of starchy endosperm in sections of grain from TaGT43_2 and TaGT47_2 RNAi transgenics showed decreased immunolabeling for xylan and arabinoxylan epitopes and approximately 50% decreased cell wall thickness compared with controls. The proportion of AX that was water soluble was not significantly affected, but average AX polymer chain length was decreased in both TaGT43_2 and TaGT47_2 RNAi transgenics. However, the long AX chains seen in controls were absent in TaGT43_2 RNAi transgenics but still present in TaGT47_2 RNAi transgenics. The results support an emerging picture of IRX9-like and IRX10-like proteins acting as key components in the xylan synthesis machinery in both dicots and grasses. Since AX is the main component of dietary fiber in wheat foods, the TaGT43_2 and TaGT47_2 genes are of major importance to human nutrition.

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Section: We-ax Chain Lengthmentioning

confidence: 83%

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confidence: 99%

RNA Interference Suppression of Genes in Glycosyl Transferase Families 43 and 47 in Wheat Starchy Endosperm Causes Large Decreases in Arabinoxylan Content

et al. 2013

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“…Firstly, we pre-form cross-linked networks of arabinoxylan as the current evidence suggests that this is relevant in vivo (Comino, Collins, Lahnstein, Beahan & Gidley, 2014;Saulnier, Sado, Branlard, Charmet & Guillon, 2007). Secondly we induce polymer concentration by cryo-gelation, which forces polymers together by their exclusion from ice crystals in a very approximate mimic of the concentration achieved by extracellular deposition of polysaccharides from adjacent turgid cells.…”

Section: Advantages and Limitations Of Cryogels As Models For Cereal mentioning

confidence: 99%

Microstructure and mechanical properties of arabinoxylan and (1,3;1,4)-β-glucan gels produced by cryo-gelation

López-Sánchez

Wang

Zhang

et al. 2016

Carbohydrate Polymers

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Microstructure and mechanical properties of arabinoxylan and (1,3;1,4)-beta;-glucan gels produced by cryogelation.Carbohydrate Polymers http://dx.doi.org/10. 1016/j.carbpol.2016.06.038 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractThe interactions between heteroxylans and mixed linkage glucans determine the architecture and mechanical properties of cereal endosperm cell walls. In this work hydrogels made of cross-linked arabinoxylan with addition of β-glucan were synthesised by cryogelation as a biomimetic tool to investigate endosperm walls. Molecular and microstructural properties were characterised by nuclear magnetic resonance ( 13 C NMR), scanning electron microscopy (SEM) and immunolabelling/confocal laser scanning 2 microscopy (CLSM). The response to mechanical stress was studied by compressionrelaxation experiments. The hydrogels consisted of a scaffold characterised by dense walls interconnected by macropores with both hemicelluloses co-localised and homogeneously distributed. The gels showed a high degree of elasticity reflected in their ability to resist compression without developing cracks and recover 60-80% of their original height. Our results highlight the compatibility of these hemicelluloses to coexist in confined environments such as cell walls and their potential role in determining mechanical properties in the absence of cellulose.

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“…Another key attribute of AX structure is the degree of feruloylation of some of the three-linked arabinose. The solubility of AX is dictated by degree of arabinose substitution (increasing solubility), cross-linking of AX chains by intermolecular dimerization of ferulate (decreasing solubility) and the chain length of AX backbone (longer chains are less soluble) (Saulnier et al 2007 ). Any of these attributes may infl uence the benefi ts that AX confers in the diet, either directly or by altering the solubility of AX.…”

Section: Variation In Ax Structurementioning

confidence: 99%

Dietary Fibre: Wheat Genes for Enhanced Human Health

Mitchell

Shewry

2015

Advances in Wheat Genetics: From Genome to Field

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The opinions expressed and arguments employed in this publication are the sole responsibility of the authors and do not necessarily refl ect those of the OECD or of the governments of its Member countries.The Special Session was sponsored by the OECD Co-operative Research Programme on Biological Resource Management for Sustainable Agricultural Systems, whose fi nancial support made it possible for most of the invited speakers to participate in the Special Session.Abstract Dietary fi bre (DF) has been shown to be a vital component of diet for human health, decreasing the risk of cardiovascular disease, type II diabetes and possibly bowel cancer. DF in wheat fl our is derived from the cell walls of the starchy endosperm, which is principally composed (~70 %) of the polysaccharide arabinoxylan (AX). Diversity screens of elite wheat germplasm have established that variation in total and water-extractable AX within fl our exists and has high heritability. Identifi cation of genes which determine AX content will assist in introduction of high DF alleles into appropriate backgrounds. We identifi ed candidate genes for the synthesis and feruloylation of AX from bioinformatics approaches. Using RNAi suppression of genes in wheat endosperm, we have shown that a glycosyl transferase (GT) family 61 gene is responsible for nearly all mono-substitution of xylose by arabinose on AX, and that genes in GT43 and GT47 families are responsible for the synthesis of the xylan backbone in AX. Using mapping populations derived from crosses of high AX x normal AX varieties, we are also seeking to identify QTLs for

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Wheat arabinoxylans: Exploiting variation in amount and composition to develop enhanced varieties

Cited by 357 publications

References 138 publications

RNA Interference Suppression of Genes in Glycosyl Transferase Families 43 and 47 in Wheat Starchy Endosperm Causes Large Decreases in Arabinoxylan Content

RNA Interference Suppression of Genes in Glycosyl Transferase Families 43 and 47 in Wheat Starchy Endosperm Causes Large Decreases in Arabinoxylan Content

Microstructure and mechanical properties of arabinoxylan and (1,3;1,4)-β-glucan gels produced by cryo-gelation

Dietary Fibre: Wheat Genes for Enhanced Human Health

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