Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom.
Plant Physiol. 2010 Mar;152(3):1209-18. doi: 10.1104/pp.109.151712. Epub 2010 Jan 20.
(1,3;1,4)-beta-d-Glucan (beta-glucan) accounts for 20% of the total cell walls in the starchy endosperm of wheat (Triticum aestivum) and is an important source of dietary fiber for human nutrition with potential health benefits. Bioinformatic and array analyses of gene expression profiles in developing caryopses identified the CELLULOSE SYNTHASE-LIKE F6 (CSLF6) gene as encoding a putative beta-glucan synthase. RNA interference constructs were therefore designed to down-regulate CSLF6 gene expression and expressed in transgenic wheat under the control of a starchy endosperm-specific HMW subunit gene promoter. Analysis of wholemeal flours using an enzyme-based kit and by high-performance anion-exchange chromatography after digestion with lichenase showed decreases in total beta-glucan of between 30% and 52% and between 36% and 53%, respectively, in five transgenic lines compared to three control lines. The content of water-extractable beta-glucan was also reduced by about 50% in the transgenic lines, and the M(r) distribution of the fraction was decreased from an average of 79 to 85 x 10(4) g/mol in the controls and 36 to 57 x 10(4) g/mol in the transgenics. Immunolocalization of beta-glucan in semithin sections of mature and developing grains confirmed that the impact of the transgene was confined to the starchy endosperm with little or no effect on the aleurone or outer layers of the grain. The results confirm that the CSLF6 gene of wheat encodes a beta-glucan synthase and indicate that transgenic manipulation can be used to enhance the health benefits of wheat products.
(1,3;1,4)-β-D-葡聚糖（β-葡聚糖）占小麦（Triticum aestivum）淀粉胚乳总细胞壁的 20%，是人类营养膳食纤维的重要来源，具有潜在的健康益处。对发育中的胚乳基因表达谱的生物信息学和阵列分析鉴定出 CELLULOSE SYNTHASE-LIKE F6（CSLF6）基因作为编码一个假定的β-葡聚糖合酶。因此，设计了 RNA 干扰构建体以下调 CSLF6 基因表达，并在淀粉质胚乳特异性 HMW 亚基基因启动子的控制下在转基因小麦中表达。使用基于酶的试剂盒和用几丁质酶消化后的高效阴离子交换色谱分析整个面粉表明，与三个对照系相比，五个转基因系中的总β-葡聚糖分别降低了 30%至 52%和 36%至 53%。在转基因系中，水可提取β-葡聚糖的含量也降低了约 50%，并且该部分的 M(r)分布从对照系中的平均 79 至 85×104g/mol 降低到转基因系中的 36 至 57×104g/mol。成熟和发育谷物的半薄切片中β-葡聚糖的免疫定位证实，转基因的影响仅限于淀粉质胚乳，对糊粉层或谷物的外层几乎没有或没有影响。结果证实，小麦的 CSLF6 基因编码β-葡聚糖合酶，并表明转基因操作可用于增强小麦产品的健康益处。
