Brachypodium distachyon grain: characterization of endosperm cell walls
Brachypodium distachyon grain: characterization of endosperm cell walls
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DOI：
10.1093/jxb/erq332
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发表时间：
2011-01-01
影响因子：
6.9
通讯作者：
Saulnier, Luc
中科院分区：
文献类型：
--
作者：
Guillon, Fabienne;Bouchet, Brigitte;Saulnier, Luc
野草 Brachypodium distachyon 已被提议作为温带谷物的替代模式物种。本文报道了二穗 B. 二穗花籽粒的特征，重点关注胚乳细胞壁。二穗短柄草以其高细胞壁多糖含量而著称，其细胞壁多糖含量接近胚乳的 52% (w/w)，而其他谷物中的多糖含量为 2-7% (w/w)。淀粉是典型的储存多糖，在胚乳中含量较低 [< 10% (w/w)]，其中主要多糖是 (1-3) (1-4)-β-葡聚糖 [40% (w/w) 的胚乳]，其很可能起到储存化合物的作用。除了(1-3)(1-4)-β-葡聚糖之外，胚乳细胞还含有大量的纤维素和木聚糖。有趣的是，二穗 B. 谷物中阿魏酸与阿拉伯木聚糖的比例高于其他研究的谷物。阿魏酰化阿拉伯木聚糖主要存在于储藏胚乳的中层和细胞连接区，表明其在细胞-细胞粘附中具有潜在作用。目前的结果表明，二穗芽孢杆菌谷物含有其他谷物中遇到的所有细胞壁多糖。因此，由于其基因组完全测序、生命周期短以及可用于诱变/转化的遗传工具，二穗芽孢杆菌是研究谷物细胞壁多糖合成和功能的良好模型。
The wild grass Brachypodium distachyon has been proposed as an alternative model species for temperate cereals. The present paper reports on the characterization of B. distachyon grain, placing emphasis on endosperm cell walls. Brachypodium distachyon is notable for its high cell wall polysaccharide content that accounts for similar to 52% (w/w) of the endosperm in comparison with 2-7% (w/w) in other cereals. Starch, the typical storage polysaccharide, is low [< 10% (w/w)] in the endosperm where the main polysaccharide is (1-3) (1-4)-beta-glucan [40% (w/w) of the endosperm], which in all likelihood plays a role as a storage compound. In addition to (1-3) (1-4)-beta-glucan, endosperm cells contain cellulose and xylan in significant amounts. Interestingly, the ratio of ferulic acid to arabinoxylan is higher in B. distachyon grain than in other investigated cereals. Feruloylated arabinoxylan is mainly found in the middle lamella and cell junction zones of the storage endosperm, suggesting a potential role in cell-cell adhesion. The present results indicate that B. distachyon grains contain all the cell wall polysaccharides encountered in other cereal grains. Thus, due to its fully sequenced genome, its short life cycle, and the genetic tools available for mutagenesis/transformation, B. distachyon is a good model to investigate cell wall polysaccharide synthesis and function in cereal grains.