UC San Diego

The cytoskeleton plays important roles in plant cell shape determination by influencing the patterns in which cell wall materials are deposited. Cortical microtubules are thought to orient the direction of cell expansion primarily via their influence on the deposition of cellulose into the wall, though the precise nature of the microtubule-cellulose relationship remains unclear. In both tip growing and diffusely growing cell types, F-actin promotes growth and also contributes to the spatial regulation of growth. F-actin has been proposed to play a variety of roles in the regulation of secretion in expanding cells, but its functions in cell growth control are not well understood. Recent work emphasized in this review on the morphogenesis of pollen tubes, epidermal trichomes (hairs) and epidermal pavement cells has yielded substantial new insights into mechanisms governing the dynamics and organization of cytoskeletal filaments in expanding plant cells, and the ways in which microtubules and F-actin interact to direct patterns of cell growth. Nevertheless, many important questions remain to be answered.