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Manipulation of cell wall synthesis to improve the dietary fibre composition of wheat flour

操纵细胞壁合成以改善小麦粉的膳食纤维成分

基本信息

批准号：
BB/F014295/1
负责人：
Rowan Mitchell
金额：
$ 65.42万
依托单位：
Rothamsted Research
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2008
资助国家：
英国
起止时间：
2008 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=BB%2FF014295%2F1
关键词：
Manipulation cell wall synthesis improve

项目摘要

Wheat white flour products play a huge role in the human diet. The manifold health benefits of fibre in foods are now well established, but the useful fibre content of wheat flour is low compared to oats and barley. This is because the major wheat flour fibre component, arabinoxylan (AX) from the endosperm cell walls, is typically only 25% soluble and it is believed to be soluble fibre that confers the most health benefits. Thus increasing the soluble fibre content of wheat flour is a major target for public health improvement. The solubility of AX is determined by its structure; greater substitution of the xylan backbone by arabinose increases solubility, but cross-linked ferulic acids attached to these arabinose units decrease solubility. We recently identified candidate genes responsible for all the key steps in the synthesis of AX including the addition of arabinose residues and feruloylation using a novel bioinformatics approach. We have now augmented this with analysis of microarray gene expression data from developing wheat grain. This in general supports our published analysis (but has caused us to revise our view on the best candidate genes encoding arabinosyl transferases) so that we have strong candidates genes for these key steps which determine the solubility of AX. The proposed research is designed (1) to provide unequivocal evidence of the function of the enzymes (2) to demonstrate that manipulation of the encoding genes in transgenic wheat has the predicted effect on the amount of soluble AX in endosperm cell walls (3) to identify changed forms of the candidate genes in a mutant wheat population which are also predicted to increase the solubility of AX. The plants carrying this form of the genes are non-GM so can be used to develop commercial wheat varieties with increased soluble fibre (4) to map the genes so that molecular markers can be found for any wheat populations which show variation in these genes. This allows wheat breeders to rapidly incorporate any beneficial versions of the genes which exist naturally in populations into commercial varieties.

小麦白色面粉产品在人类饮食中起着巨大的作用。食物中纤维的多种健康益处现在已经得到了很好的证实，但与燕麦和大麦相比，小麦粉中有用的纤维含量较低。这是因为小麦粉纤维的主要成分，即来自胚乳细胞壁的阿拉伯木聚糖（AX），通常只有25%可溶，并且被认为是赋予最大健康益处的可溶性纤维。因此，增加小麦粉中的可溶性纤维含量是改善公众健康的一个主要目标。AX的溶解度由其结构决定;木聚糖主链被阿拉伯糖的更大取代增加溶解度，但连接到这些阿拉伯糖单元的交联阿魏酸降低溶解度。我们最近确定了候选基因负责所有的关键步骤，包括在合成的AX，阿拉伯糖残基和阿魏酰化使用一种新的生物信息学方法添加。我们现在通过分析来自发育中小麦籽粒的微阵列基因表达数据来增强这一点。这在总体上支持了我们发表的分析（但导致我们修改了我们对编码阿拉伯糖基转移酶的最佳候选基因的观点），使得我们对于这些决定AX溶解度的关键步骤具有强候选基因。所提出的研究旨在（1）提供酶功能的明确证据（2）证明转基因小麦中编码基因的操作对胚乳细胞壁中可溶性AX的量具有预测的影响（3）鉴定突变小麦群体中候选基因的变化形式，这些变化形式也预测会增加AX的溶解度。携带这种形式的基因的植物是非转基因的，因此可以用于开发具有增加的可溶性纤维的商业小麦品种（4）以绘制基因，从而可以为显示这些基因变异的任何小麦群体找到分子标记。这使得小麦育种者能够迅速地将自然存在于群体中的任何有益的基因版本整合到商业品种中。