Pulvinar slits: Cellulose-deficient and de-methyl-esterified pectin-rich structures in a legume motor cell
Pulvinar slits: Cellulose-deficient and de-methyl-esterified pectin-rich structures in a legume motor cell
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DOI：
10.1093/plphys/kiad105
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发表时间：
2023-02-28
期刊：
影响因子：
7.4
通讯作者：
Nakata, Miyuki T.
中科院分区：
文献类型：
--
作者：
Takahara, Masahiro;Tsugawa, Satoru;Nakata, Miyuki T.
豆科植物的皮质运动细胞（CMCs）在叶片运动中执行由胀压变化驱动的可逆变形。与潜在的渗透调节特性相反，cmc的细胞壁结构对运动的贡献尚未得到详细的表征。在这里，我们报道了cmc细胞壁具有低水平纤维素沉积的周向狭缝，这在豆科植物中广泛保守。这种结构是独特的，与迄今为止报道的任何其他原代细胞壁不同；因此，我们将它们命名为“pulvinar狭缝”。值得注意的是，我们主要在pulvinar狭缝内检测到去甲基化的均半乳糖酸，与纤维素一样，高度甲基化的均半乳糖酸沉积较少。此外，傅里叶变换红外光谱分析表明，蒲公英的细胞壁组成与叶柄或茎等其他轴器官不同。此外，单糖分析表明，蒲公英与发育中的茎一样是富含果胶的器官，且蒲公英中半乳糖醛酸的含量高于发育中的茎。计算机模拟表明，在胀压存在的情况下，pulvinar狭缝有利于垂直于狭缝方向的各向异性扩展。当cmc的组织切片被转移到不同的细胞外渗透条件时，枕侧狭缝改变了其开口宽度，表明其可变形性。在这项研究中，我们因此表征了cmc的独特细胞壁结构，增加了我们对重复和可逆器官变形以及植物细胞壁结构多样性和功能的了解。在豆科运动细胞中发现了初代细胞壁的独特结构，“pulvinar狭缝”，研究结果表明它们在叶片运动过程中重复和可逆变形中的作用。
The cortical motor cells (CMCs) in a legume pulvinus execute the reversible deformation in leaf movement that is driven by changes in turgor pressure. In contrast to the underlying osmotic regulation property, the cell wall structure of CMCs that contributes to the movement has yet to be characterized in detail. Here, we report that the cell wall of CMCs has circumferential slits with low levels of cellulose deposition, which are widely conserved among legume species. This structure is unique and distinct from that of any other primary cell walls reported so far; thus, we named them "pulvinar slits." Notably, we predominantly detected de-methyl-esterified homogalacturonan inside pulvinar slits, with a low deposition of highly methyl-esterified homogalacturonan, as with cellulose. In addition, Fourier transform infrared spectroscopy analysis indicated that the cell wall composition of pulvini is different from that of other axial organs, such as petioles or stems. Moreover, monosaccharide analysis showed that pulvini are pectin-rich organs like developing stems and that the amount of galacturonic acid in pulvini is greater than in developing stems. Computer modeling suggested that pulvinar slits facilitate anisotropic extension in the direction perpendicular to the slits in the presence of turgor pressure. When tissue slices of CMCs were transferred to different extracellular osmotic conditions, pulvinar slits altered their opening width, indicating their deformability. In this study, we thus characterized a distinctive cell wall structure of CMCs, adding to our knowledge of repetitive and reversible organ deformation as well as the structural diversity and function of the plant cell wall.Unique structures in the primary cell wall, "pulvinar slits," are discovered in a legume motor cell and findings suggest their role in repetitive and reversible deformation during leaf movement.