The role of pectin in plant morphogenesis.

The presence of a polysaccharidic cell wall distinguishes plant cells from animal cells and is responsible for fundamental mechanistic differences in organ development between the two kingdoms. Due to the presence of this wall, plant cells are unable to crawl and contract. On the other hand, plant cell size can increase by several orders of magnitude and cell shape can change from a simple polyhedron or cube to extremely intricate. This expansive cellular growth is regulated by the interaction between the cell wall and the intracellular turgor pressure. One of the principal cell wall components involved in temporal and spatial regulation of the growth process is pectin. Through biochemical changes to pectin composition and biochemical configuration, the properties of this material can be altered to trigger specific developmental processes. Here, the roles of pectin in three systems displaying rapid growth - the elongation zone of the root, the tip region of the pollen tube, and organ primordia formation at the shoot apical meristem - are reviewed.