Abstract
Unlike most animal cells, plant cells are thought to be totipotent because they can regenerate the full array of tissues from fully differentiated tissue explants under proper culture conditions. The mechanism behind the totipotency of plant cells is largely unknown. Even the basic questions regarding what differentiation status cells go through during regeneration and whether the regeneration from different tissues is accomplished by the common processes are yet to be answered. We characterized the nature of callus, which is a mass of growing cells induced during the regeneration process prior to a new organ formation. Using live imaging and whole-genome microarray analysis, we found that callus is a tissue similar to the tip part of root meristem even if it is derived from the aerial organs. Moreover, mutant analysis suggested that callus formation and lateral root formation are under the same genetic control at the initiation step.
