Calcium Binding by Arabinogalactan Polysaccharides Is Important for Normal Plant Development.
Calcium Binding by Arabinogalactan Polysaccharides Is Important for Normal Plant Development.
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DOI：
10.1105/tpc.20.00027
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发表时间：
2020-10
期刊：
影响因子：
--
通讯作者：
Dupree P
中科院分区：
文献类型：
--
作者：
Lopez-Hernandez F;Tryfona T;Rizza A;Yu XL;Harris MOB;Webb AAR;Kotake T;Dupree P
拟南芥阿拉伯半乳聚糖蛋白生物合成突变体的分离和表征表明，这种细胞表面蛋白聚糖可以为细胞内信号传导途径提供钙。阿拉伯半乳聚糖蛋白（AGP）是参与许多生理事件的植物细胞外蛋白聚糖家族。 AGP 通常锚定在质膜的细胞外侧，并被阿拉伯半乳聚糖 (AG) 多糖高度糖基化，但这种糖基化的分子功能仍然很大程度上未知。 AG 多糖中的 β-连接葡萄糖醛酸 (GlcA) 残基已在体外显示以 pH 依赖性方式与钙结合。在这里，我们使用拟南芥（Arabidopsis thaliana）的四种 AG β-葡萄糖醛酸转移酶（GlcAT14A、-B、-D 和 -E）突变体来了解 AG 葡萄糖醛酸化的作用。从 glcat14 三重突变体中分离出的 AG 的葡萄糖醛酸化作用显着减少。来自 glcat14a/b/d 三重突变体的 AG 在体外具有比来自野生型植物的 AG 更低的钙结合能力。一些突变体具有多种发育缺陷，例如毛状体分支减少。 glcat14a/b/e 三重突变植物的幼苗生长受到严重限制并且不育，根部钙波的传播受到干扰。通过增加生长培养基中的钙浓度，可以抑制一些发育表型。我们的结果表明，AG 葡萄糖醛酸化对于植物的多个发育过程至关重要，并表明 AGP 的功能可能是结合和释放细胞表面质外体钙。
Isolation and characterization of Arabidopsis arabinogalactan protein biosynthesis mutants suggest that this cell-surface proteoglycan can provide calcium for intracellular signaling pathways. Arabinogalactan proteins (AGPs) are a family of plant extracellular proteoglycans involved in many physiological events. AGPs are often anchored to the extracellular side of the plasma membrane and are highly glycosylated with arabinogalactan (AG) polysaccharides, but the molecular function of this glycosylation remains largely unknown. The β-linked glucuronic acid (GlcA) residues in AG polysaccharides have been shown in vitro to bind to calcium in a pH-dependent manner. Here, we used Arabidopsis (Arabidopsis thaliana) mutants in four AG β-glucuronyltransferases (GlcAT14A, -B, -D, and -E) to understand the role of glucuronidation of AG. AG isolated from glcat14 triple mutants had a strong reduction in glucuronidation. AG from a glcat14a/b/d triple mutant had lower calcium binding capacity in vitro than AG from wild-type plants. Some mutants had multiple developmental defects such as reduced trichome branching. glcat14a/b/e triple mutant plants had severely limited seedling growth and were sterile, and the propagation of calcium waves was perturbed in roots. Several of the developmental phenotypes were suppressed by increasing the calcium concentration in the growth medium. Our results show that AG glucuronidation is crucial for multiple developmental processes in plants and suggest that a function of AGPs might be to bind and release cell-surface apoplastic calcium.
影响因子：
4.3
作者：
Endo M;Kotake T;Watanabe Y;Kimura K;Tsumuraya Y
通讯作者：
Tsumuraya Y