The Cell Wall of the Arabidopsis Pollen Tube-Spatial Distribution, Recycling, and Network Formation of Polysaccharides
The Cell Wall of the Arabidopsis Pollen Tube-Spatial Distribution, Recycling, and Network Formation of Polysaccharides
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DOI：
10.1104/pp.112.199729
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发表时间：
2012-12-01
期刊：
影响因子：
7.4
通讯作者：
Geitmann, Anja
中科院分区：
文献类型：
--
作者：
Chebli, Youssef;Kaneda, Minako;Geitmann, Anja
在开花植物中，花粉管是由花粉粒或雄配子体形成的细胞突起。它的主要代谢活动是细胞壁物质的合成和组装，必须精确协调以维持特征性的快速生长速率，并确保几何正确和有效的细胞形态发生。与其他模式物种不同，拟南芥（Arabidopsis thaliana）花粉管的细胞壁尚未被详细描述。我们使用免疫组织化学和定量图像分析提供了一个详细的配置文件的主要细胞壁聚合物组成的拟南芥花粉管细胞壁的空间分布。通过与花粉管生长的力学模型预测的比较，揭示了果胶脱酯化在确定细胞直径中的重要性。扫描电子显微镜表明，纤维素微纤丝在拟南芥花粉管细胞壁中以近纵向取向取向，与纤维素合酶CESA 6在质膜中的线性排列一致。纤维素标签也被发现细胞质囊泡内，可能源于纤维素酶的早期激活之前，他们插入质膜或从回收短纤维素聚合物的内吞作用。一系列的战略酶处理也表明，果胶，纤维素和胼胝质是高度交联的。
The pollen tube is a cellular protuberance formed by the pollen grain, or male gametophyte, in flowering plants. Its principal metabolic activity is the synthesis and assembly of cell wall material, which must be precisely coordinated to sustain the characteristic rapid growth rate and to ensure geometrically correct and efficient cellular morphogenesis. Unlike other model species, the cell wall of the Arabidopsis (Arabidopsis thaliana) pollen tube has not been described in detail. We used immunohistochemistry and quantitative image analysis to provide a detailed profile of the spatial distribution of the major cell wall polymers composing the Arabidopsis pollen tube cell wall. Comparison with predictions made by a mechanical model for pollen tube growth revealed the importance of pectin deesterification in determining the cell diameter. Scanning electron microscopy demonstrated that cellulose microfibrils are oriented in near longitudinal orientation in the Arabidopsis pollen tube cell wall, consistent with a linear arrangement of cellulose synthase CESA6 in the plasma membrane. The cellulose label was also found inside cytoplasmic vesicles and might originate from an early activation of cellulose synthases prior to their insertion into the plasma membrane or from recycling of short cellulose polymers by endocytosis. A series of strategic enzymatic treatments also suggests that pectins, cellulose, and callose are highly cross linked to each other.