Analysis of cell division patterns in the Arabidopsis shoot apical meristem
The stereotypic pattern of cell shapes in the Arabidopsis shoot apical meristem (SAM) suggests that strict rules govern the placement of new walls during cell division. When a cell in the SAM divides, a new wall is built that connects existing walls and divides the cytoplasm of the daughter cells. Because features that are determined by the placement of new walls such as cell size, shape, and number of neighbors are highly regular, rules must exist for maintaining such order. Here we present a quantitative model of these rules that incorporates different observed features of cell division. Each feature is incorporated into a "potential function" that contributes a single term to a total analog of potential energy. New cell walls are predicted to occur at locations where the potential function is minimized. Quantitative terms that represent the well-known historical rules of plant cell division, such as those given by Hofmeister, Errera, and Sachs are developed and evaluated against observed cell divisions in the epidermal layer (L1) of Arabidopsis thaliana SAM. The method is general enough to allow additional terms for nongeometric properties such as internal concentration gradients and mechanical tensile forces.
© 2015 National Academy of Sciences. Contributed by Elliot M. Meyerowitz, February 14, 2015 (sent for review June 5, 2013; reviewed by Jacques Dumais, Lionel Xavier Dupuy, and Christophe Godin). This work was supported by grants from the Beckman Institute at California Institute of Technology, the Division of Biology, and the Provost's Office at California Institute of Technology; a gift from Peter Cross; and Department of Energy Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences of the US Department of Energy Grant DE-FG02-88ER13873 (to E.M.M.). The E.M.M. laboratory is also supported by funds from the Howard Hughes Medical Institute and the Gordon and Betty Moore Foundation (through Grant GBMF3406). Funding for E.M. was provided by NIH Grants R01-GM086883 and P50GM76516 to University of California, Irvine. B.E.S. and C.T. contributed equally to this work. Author contributions: B.E.S., C.T., E.M., and E.M.M. designed research; C.T. performed research; B.E.S., C.T., and E.M. analyzed data; and B.E.S., C.T., E.M., and E.M.M. wrote the paper. Reviewers: J.D., Universidad Adolfo Ibáñez; L.X.D., The James Hutton Institute; and C.G., Inria. The authors declare no conflict of interest. This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1502588112/-/DCSupplemental.
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Supplemental Material - pnas.1502588112.sapp.pdf