A myosin inhibitor impairs auxin-induced cell division

The role of myosins for auxin-induced cell division was probed using the inhibitor 2,3-butanedione monoxime in the tobacco cell line VBI-0, where cell elongation and division are axially aligned under the control of auxin. A morphometric analysis revealed that cell division is blocked in a dose-dependent manner, whereas cell expansion continued. In addition, the polarity of terminal cells was impaired resulting in malformed, pear-shaped cells. Early effects of the inhibitor are aberrant features of the cytoarchitecture including a block of vesicle transport, a diffuse broadening of cross walls, and the disorganization of the actin cytoskeleton. The findings are discussed with respect to a possible role of myosins as link between vesicle flow and signal control of cell division.