CELLULOSE SYNTHASE-LIKE A2, a Glucomannan Synthase, Is Involved in Maintaining Adherent Mucilage Structure in Arabidopsis Seed1[C][W]
CELLULOSE SYNTHASE-LIKE A2, a Glucomannan Synthase, Is Involved in Maintaining Adherent Mucilage Structure in Arabidopsis Seed1[C][W]
复制标题
类纤维素合酶 A2 是一种葡甘聚糖合酶，参与维持拟南芥种子的粘附粘液结构(1[C][W])
DOI：
10.1104/pp.114.236596
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发表时间：
2014-04-01
期刊：
影响因子：
7.4
通讯作者：
Zhou, Gongke
中科院分区：
文献类型：
--
作者：
Yu, Li;Shi, Dachuan;Zhou, Gongke
甘露聚糖是半纤维素多糖，被认为在植物细胞壁中具有结构和储存功能。然而，目前尚不清楚甘露聚糖在拟南芥（Arabidopsis thaliana）种子粘液中如何发挥作用。在这项研究中，在几种种子组织中观察到纤维素合成酶样 A2（CSLA2；At5g22740）表达，包括发育中种皮的表皮细胞。 CSLA2 的破坏导致粘附粘液晕变薄，尽管粘附粘液总量与野生型相比没有变化。这表明突变体中的粘附粘液比野生型更致密。根据 CSLA2 在葡甘露聚糖合成中的作用，csla2-1 粘液中的甘露糖基和葡萄糖基含量比野生型少 30%。突变体粘液中的非甘露聚糖多糖的组成、结构或大分子特性没有观察到明显的变化。生化分析表明，csla2-1 粘液中的纤维素结晶度大幅降低；通过用内切 β-葡聚糖酶处理 csla2-1 种子，去除了大部分粘液纤维素，从而支持了这一点。 CSLA2 的突变还导致纤维素空间分布的改变以及粘附粘液内双折射纤维素微纤维的缺失。与观察到的结晶纤维素的变化一样，csla2-1 粘液中果胶的空间分布也发生了变化。综上所述，我们的结果表明，CSLA2 合成的葡甘露聚糖可能通过改变纤维素组织和结晶来参与调节粘附粘液的结构。
Mannans are hemicellulosic polysaccharides that are considered to have both structural and storage functions in the plant cell wall. However, it is not yet known how mannans function in Arabidopsis (Arabidopsis thaliana) seed mucilage. In this study, CELLULOSE SYNTHASE-LIKE A2 (CSLA2; At5g22740) expression was observed in several seed tissues, including the epidermal cells of developing seed coats. Disruption of CSLA2 resulted in thinner adherent mucilage halos, although the total amount of the adherent mucilage did not change compared with the wild type. This suggested that the adherent mucilage in the mutant was more compact compared with that of the wild type. In accordance with the role of CSLA2 in glucomannan synthesis, csla2-1 mucilage contained 30% less mannosyl and glucosyl content than did the wild type. No appreciable changes in the composition, structure, or macromolecular properties were observed for nonmannan polysaccharides in mutant mucilage. Biochemical analysis revealed that cellulose crystallinity was substantially reduced in csla2-1 mucilage; this was supported by the removal of most mucilage cellulose through treatment of csla2-1 seeds with endo-beta-glucanase. Mutation in CSLA2 also resulted in altered spatial distribution of cellulose and an absence of birefringent cellulose microfibrils within the adherent mucilage. As with the observed changes in crystalline cellulose, the spatial distribution of pectin was also modified in csla2-1 mucilage. Taken together, our results demonstrate that glucomannans synthesized by CSLA2 are involved in modulating the structure of adherent mucilage, potentially through altering cellulose organization and crystallization.