Plant biology

Asymmetric Division in Plant Development

Science Signaling  03 Feb 2009:
Vol. 2, Issue 56, pp. ec45
DOI: 10.1126/scisignal.256ec45

In plants, as in other multicellular eukaryotes, asymmetric divisions are used to generate pattern and diversity during development. Asymmetric divisions must be oriented properly within their developmental context, but very little is known about how this is accomplished in plants. Plants lack proteins universally employed for polarization of asymmetric cell divisions in animals and pathways involved in orienting animal cell polarity. About 50 years ago, it was proposed, based on observations of cell division patterns in developing grass leaves, that the asymmetric divisions of subsidiary mother cells, which give rise to subsidiary cells of the stomatal complex, are polarized by the adjacent guard mother cell, the precursor of stomatal guard cells. Cartwright et al. (see the Perspective by Sack and Chen) implicate a receptor-like protein, PAN1, in transmission of a guard mother cell–derived signal that polarizes subsidiary mother cells in preparation for their asymmetric division. Thus, asymmetric cell division can be polarized in response to an extracellular cue in plants.

H. N. Cartwright, J. A. Humphries, L. G. Smith, PAN1: A receptor-like protein that promotes polarization of an asymmetric cell division in maize. Science 323, 649–651 (2009). [Abstract] [Full Text]

F. D. Sack, J.-G. Chen, Pores in place. Science 323, 592–593 (2009). [Summary] [Full Text]