Cell division and cell expansion are essential for proper tissue and organ formation during growth and development. We are interested in molecular mechanisms which determine division plane selection and orientation of cell expansion in growing plant cells. Plant cells are surrounded by rigid cell walls which fix their positions relative to neighbors. Positioning of new cell walls during cell division, and orientation of cellulose microfibrils during cell expansion are crucial in tissue and organ development. Microtubules (MTs) plays an integral role in both of these processes and our research is focused on understading how the MT cytoskeleton guides cell division and cell expansion.