Visualization of Cytoskeleton Organization and Dynamics in Elongating Cotton Fibers by Live-Cell Imaging.

Cotton fibers are extremely elongated single cells and have long been regarded as an ideal model to investigate polarized plant cell elongation. Actin filaments (F-actin), as well as the cortical microtubules (CMTs), play vital roles in polarized cell growth and morphogenesis. We have generated stable transgenic cotton plants expressing fluorescent markers for the actin and microtubule cytoskeletons. Further live-cell imaging identified dynamic features of the F-actin and cortical microtubule (CMT) architectures and discovered that cotton fibers elongate in a unique tip-biased diffuse growth mode. Here, we describe methods for preparing growing cotton fiber samples, as well as the visualization of cytoskeletal organization and dynamics by live-cell imaging. Combined with comprehensive image analyses, these methods can be used to identify how cytoskeleton organization and dynamics determine cell morphogenesis in highly polarized cotton fibers.