Editors' ChoicePlant biology

The Yin Yang of Root Regulation

Science Signaling  02 Dec 2008:
Vol. 1, Issue 48, pp. ec415
DOI: 10.1126/scisignal.148ec415

The root meristem is a group of stem cells at the root tip that give rise to differentiated root tissues. The root meristem exists as a balance between new cells added by proliferation and daughter cells removed by differentiation. The plant hormone auxin seems to oversee meristem cell proliferation, whereas the plant hormone cytokinin oversees differentiation. Using Arabidopsis plants, mutants, and expression and chromatin analysis, Dello Ioio et al. find that signaling pathways from the two hormones converge on the SHY2 gene. Cytokinin activates the SHY2 gene, the effects of which cascade toward redistributing auxin. Auxin, on the other hand, directs degradation of the SHY2 protein, thus stabilizing auxin distribution.

R. Dello Ioio, K. Nakamura, L. Moubayidin, S. Perilli, M. Taniguchi, M. T. Morita, T. Aoyama, P. Costantino, S. Sabatini, A genetic framework for the control of cell division and differentiation in the root meristem. Science 322, 1380–1384 (2008). [Abstract] [Full Text]

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