Cell wall evolution and diversity

Abstract

Cell walls of green plants and other photosynthetic eukaryotes consist of complex polysaccharide-rich coverings that are central to cell growth, development, and defense. Most cell walls display a microarchitectural design consisting of a composite of fibrillar polysaccharides, such as cellulose, mannans, or xylans, tethered by other glycans (e.g., hemicelluloses) that are embedded in a matrix of polysaccharides and proteins. This design produces both remarkable strength and the capacity for controlled expansion. The biosynthesis and metabolism of the cell wall require a significant portion of the cell’s genetic machinery and the activities of coordinated subcellular pathways that are, in turn, responsive to developmental and environmental signals. The evolution of cell walls was critical to the exploitation of, and survival in, Earth’s diverse habitats.