From Cell Division to Organ Shape: Nitric Oxide Is Involved in Auxin-Mediated Root Development

Roots are plant organs that mainly function to acquire water and nutrients from soil. Root development is under the control of a regulated cell proliferation and morphogenesis, and auxin is the central plant hormone that governs those processes. In this review we discuss new aspects of the mechanisms that operate during root organogenesis. We particularly emphasize the analyses of downstream signals involved in the auxin control of root development. Nitric oxide (NO), an emerging chemical messenger that plays a significant role in a broad spectrum of plant developmental processes, is a key component in the signal transduction pathways that determine root architecture. Lateral root development as well as adventitious root formation are strictly NO-dependent processes in the auxin-promoted root organogenesis.