Cellulose Biosynthesis in Higher Plants and the Role of the Cytoskeleton

Abstract

Cellulose is a polysaccharide consisting of a linear chain of β (1→4) linked D ‐glucose and it is the most abundant polymer on earth. As a major structural component of the cell wall, cellulose accounts for about one‐third of plant mass. The regulation of cellulose biosynthesis is essential to plant development. Cellulose is synthesised by the cellulose synthase (CESA) complex in the plasma membrane. This article reviews the composition and regulation of the cellulose synthase complex with a focus on the role of cytoskeleton in higher plants. In this article, the evolving views in the field of cellulose biosynthesis are discussed and the unresolved questions, such as in vitro cellulose synthesis, structure of CESA and mechanism underlying microtubule–microfibril alignment hypothesis, are highlighted. Key Concepts: Cellulose is a polysaccharide consisting of a linear chain of β (1→4) linked D ‐glucose. Cellulose is synthesised by large membrane‐bound protein complexes known as cellulose synthase complexes (CSCs). Microtubule–microfibril alignment hypothesis states that there is a causal link between the orientation of cortical microtubules and nascent microfibrils. Primary cell wall surrounds all plant cells and is formed during cell division and expansion. Secondary cell wall is formed between the primary cell wall and the plasma membrane in cells that are subject to mechanical stress.

Cell Wall, Cytoskeleton, and Cell Expansion in Higher Plants

“…Tremendous effort has been put into the study of cell wall structure and formation over the past two decades not only due to interest in the biological perplexities of the cell wall function in plants, but also due to the dependence of society on the utilization of cell wall material by the timber, pulp, paper, and cellulosic biofuel industries. Many outstanding reviews cover the recent progress in the rapidly expanding field of plant cell walls (Cosgrove, 2005;Saxena and Brown, 2005;Somerville, 2006;Joshi and Mansfield, 2007;Mohnen, 2008;Guerriero et al, 2010;Scheller and Ulvskov, 2010;Fujita et al, 2012;Li and Gu, 2012;Wolf et al, 2012a;Li et al, 2014). As the major load-bearing cell wall polymer, cellulose will be the central focal point in a majority of our discussion on how several properties of the biosynthesis and organization of the plant cell wall influence cell expansion.…”

Cellulose Synthesis and Its Regulation

“…Cellulose biosynthesis in higher plants is a tightly regulated process (Brabham et al, 2012;Li et al, 2012b). For example, the amount of cellulose, the ratio of cellulose to other cell wall polymers, the degree of polymerization, the crystalline cellulose core size, and the orientation of cellulose microfibrils are under tight control.…”