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Integrating cell division and growth in the Arabidopsis leaf

Florent Pantin
John Innes Centre, Norwich Research Park, Norwich, UK
le 27/03/2014 à 16:45


Small primordia with a few cells develop into differentiated organs with a consistent shape. Such a morphogenesis requires a spatiotemporal coordination between cell division and cell growth. How this coordination is achieved remains largely unknown. We addressed this question on the Arabidopsis leaf using time-lapse imaging and finite element modelling. In the Arabidopsis leaf, cell division occurs at early developmental stages before it arrests rapidly from the tip to the base of the leaf (Kazama et al, 2010, PCP; Andriankaja et al, 2012, Dev Cell). Similarly, growth varies over space and time, with higher expansion rates at the leaf base and during the early developmental stages. A model was developed in our group which accounts for this spatiotemporal pattern of leaf growth (Kuchen et al, Science, 2012). The local direction of growth is provided through a dynamic polarity field; the magnitude of growth parallel and perpendicular to this polarity field is then specified non-uniformly across the leaf using morphogen gradients. This growth model was extended to account for the pattern of cell division using the same set of morphogens. Model outputs were compared to data obtained using a chamber fitted within a confocal microscope, allowing us to directly track cell division and growth at a high temporal resolution. Overall, the hypothesis is quantitatively plausible that cell expansion and growth are governed by the same set of morphogens.