Mechanistic Insights into Plant Chiral Growth
Mechanistic Insights into Plant Chiral Growth
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DOI：
10.3390/sym12122056
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发表时间：
2020-12
期刊：
影响因子：
--
通讯作者：
Masayoshi Nakamura;T. Hashimoto
中科院分区：
文献类型：
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作者：
Masayoshi Nakamura;T. Hashimoto
维管束植物潜在的左右不对称（手性）表现在爬升植物的圆柱形器官呈螺旋状伸长。有趣的是，螺旋手性在特定物种中通常是固定的，这表明手性是由遗传控制的。拟南芥（Arabidopsis thaliana）是一种小型芥菜植物，通常不会扭曲，但可以在细长的器官中突变成螺旋状生长。对这些扭曲突变体的遗传、分子和细胞生物学分析提供了关于左右利手性的机制见解，以及大多数植物中潜在的器官倾斜是如何被抑制的。植物细胞的生长方向是由细胞壁中纤维素微原纤维的排列决定的，这是由位于质膜下方的皮质微管引导的。微管组装或组织的微管蛋白和调节因子的突变导致拟南芥细胞皮层微管阵列的螺旋排列，并导致轴向器官（如根和茎）中固定手性的螺旋生长。微管是否组装成由直的或倾斜的原丝组成的微管可能决定笔直的或扭曲的生长。了解植物螺旋生长的机理将为研究蛋白质丝结构与细胞组织的联系提供一个范例。
The latent left–right asymmetry (chirality) of vascular plants is best witnessed as a helical elongation of cylindrical organs in climbing plants. Interestingly, helical handedness is usually fixed in given species, suggesting genetic control of chirality. Arabidopsis thaliana, a small mustard plant, normally does not twist but can be mutated to exhibit helical growth in elongating organs. Genetic, molecular and cell biological analyses of these twisting mutants are providing mechanistic insights into the left–right handedness as well as how potential organ skewing is suppressed in most plants. Growth direction of elongating plant cells is determined by alignment of cellulose microfibrils in cell walls, which is guided by cortical microtubules localized just beneath the plasma membrane. Mutations in tubulins and regulators of microtubule assembly or organization give rise to helical arrangements of cortical microtubule arrays in Arabidopsis cells and cause helical growth of fixed handedness in axial organs such as roots and stems. Whether tubulins are assembled into a microtubule composed of straight or tilted protofilaments might determine straight or twisting growth. Mechanistic understanding of helical plant growth will provide a paradigm for connecting protein filament structure to cellular organization.