Purdue Study Finds Key to Plant Growth Mechanism

A study from Purdue University led by Daniel Szymanski has mapped a complex series of pathways that control the shape of plant cells. The research team used the model plant Arabidopsis to map the complex pathways that control plant cell shape. The findings may be a key to improving the quality of cotton grown in the United States. Szymanski, professor in the Department of Botany and Plant Pathology, analyzed how intracellular signaling networks pattern cell walls to generate particular cell shapes and sizes. In a paper published in Current Biology, Szymanski described how microtubules and actin, protein polymers that form the cytoskeletons of plant cells, are organized to specify the mechanical properties of cell walls that define cell shape. The research group found that microtubules entrap a protein called SPIKE 1 within the apex of another cell where SPIKE 1 recruits additional protein machinery that causes actin filaments to form. Actin filament networks are then organized as roadways for long-distance intracellular transport and the regulated delivery of cell wall materials that are necessary for cell growth. According to Szymanski, SPIKE 1 is a master regulator in cells, a switch that when activated determines the time and location where actin networks are polymerized. He added that the location and activity of SPIKE1 are important. Without it, growth is misregulated, leading to distorted cell shapes that do not taper properly.