Department of Biology, Penn State University, University Park, PA 16803, USA.
Curr Opin Plant Biol. 2018 Dec;46:77-86. doi: 10.1016/j.pbi.2018.07.016. Epub 2018 Aug 22.
This article briefly reviews recent advances in nano-scale and micro-scale assessments of primary cell wall structure, mechanical behaviors and expansive growth. Cellulose microfibrils have hydrophobic and hydrophilic faces which may selectively bind different matrix polysaccharides and adjacent microfibrils. These distinctive binding interactions may guide partially aligned cellulose microfibrils in primary cell walls to form a planar, load-bearing network within each lamella of polylamellate walls. Consideration of expansive growth of cross-lamellate walls leads to a surprising inference: side-by-side sliding of microfibrils may be a key rate-limiting physical step, potentially targeted by specific wall loosening agents. Atomic force microscopy shows different patterns of microfibril movement during force-driven extension versus enzymatic loosening. Consequently, simulations of cell growth as elastic deformation of isotropic cell walls may need to be augmented to incorporate the distinctive behavior of growing cell walls.
本文简要回顾了近年来在原细胞壁结构、力学行为和膨胀生长的纳微尺度评估方面的进展。纤维素微纤维具有疏水和亲水的表面，可能选择性地结合不同的基质多糖和相邻的微纤维。这些独特的结合相互作用可能指导原细胞壁中部分排列的纤维素微纤维形成一个平面的、承载负荷的网络，存在于多层面壁的每一层中。考虑到交层面壁的膨胀生长，会得出一个惊人的推断：微纤维的并排滑动可能是一个关键的限速物理步骤，可能是特定的壁松弛剂的作用靶点。原子力显微镜显示了在力驱动的伸展过程中与酶松弛过程中微纤维运动的不同模式。因此，需要对作为各向同性细胞壁弹性变形的细胞生长进行模拟，以纳入生长细胞壁的独特行为。
