Cooperation Between Auxin and Actin During the Process of Plant Polar Growth

Abstract

Polar growth is provided by rapid cell expansion that spatially focuses at the tip. The regulation and maintenance of polar growth requires two important intracellular events: intensive exocytosis in the tip region and a highly dynamic cytoskeleton system. The selective transport of secretory vesicles and their accumulation in the apical region, which is driven by motor proteins that move along actin cables, is critical for plant polar growth. The regulation of vesicle trafficking and actin cytoskeleton turnover is affected by several intracellular components and signaling pathways. Auxin as one of the most important intracellular elements regulating plant growth and development involved in numerous signaling pathways that can affect the organization and dynamics of cell cytoskeleton is a potential candidate as a polar growth regulator. The current knowledge is summarized here in order to highlight the role of auxin in plant polar growth regulation and the cooperation between auxin and the actin cytoskeleton during this process.