Auxin: Molecular genetic approaches in Arabidopsis

The plant hormone auxin is important in many plant processes. Recent results from studies on Arabidopsis have defined genes important for the regulation of auxin levels, auxin responses, and auxin transport. Mutants isolated with defects in other processes, ranging from lateral root formation to embryonic development, have also been shown to be altered in auxin pathways. Significant evidence from these studies now implicates ubiquitin-mediated regulation of the cell cycle as important in auxin response. However, much remains to be done to clarify the mechanism of auxin action, auxin transport, and the roles of auxin in plant physiology.