The role of Auxin and Cytokinins in Cambium Development

  • Siligato, Riccardo (Deltagare)



The vascular cambium is a secondary meristem producing phloem centrifugally and xylem centripetally. It has been demonstrated that the cambial activity depends on the role of different phytohormones like auxin, cytokinins, gibberellins and ethylene, even though the molecular mechanisms by which these hormones regulate cambium activity have remained largely poorly understood. In tree studies, an auxin maximum was found in the stem cambium ring, and it has been widely demonstrated that cytokinins are required for the correct activity of cambium in tree stem and Arabidopsis root.
The crosstalk between auxin and cytokinins has been identified as a central driver of tissue patterning in Arabidopsis, such as in embryo development, root meristem size maintenance, shoot stem-cell niche control, lateral root formation and primary pattering of the root vasculature. During the primary development of root vasculature auxin and cytokinins show distinct domains: auxin response is focused in the xylem axis, while cytokinin response is present in procambial cells. These domains are maintained by mutual interaction between these two hormones: high cytokinin signaling in the procambial cells promotes expression of PINFORMED (PIN) 1, 3 and 7 thus channeling the auxin accumulation in the xylem axis. High auxin signaling, in turn, promotes the expression of the cytokinin signaling inhibitor AHP6 and the xylem identity gene AtHB8. However, it is currently unknown whether similar auxin-cytokinin crosstalk regulates secondary development as well.
Gällande start-/slutdatum18/04/2011 → …


  • 1183 Växtbiologi, mikrobiologi, virologi