Olivier Hamant, INRA, CNRS, ENS, Universite de Lyon, Mechanical signals in plant morphogenesis

Event Dates: August 4, 2014 - 4:00pm - 5:00pm

Development heavily relies on folding events and the relevant mechanisms are currently being investigated both in plants and animals. We address this question in the shoot apical meristem, which generate all the aerial organs of the plant, and where tissue folding occurs at the boundary between the meristematic dome and the growing organ. We found that mechanical signals control the orientation of cortical microtubules, which guide the deposition of cellulose and thus control the mechanical anisotropy of plant cell walls. This in turn promotes tissue folding, which further consolidates the stress pattern. Remarkably, this feedback loop also exists at the single cell level, as illustrated in the jigsaw puzzle shape pavement cells form the leaf epidermis. Furthermore, we found that the expression of genes that are expressed in the boundary is correlated with the extent of folding and that mechanical stress can trigger their expression, providing another feedback loop in which tissue folding contributes to the robustness of gene expression patterns. Prospects for this work are numerous and will be discussed in the talk.