AgreenSkills session, year: 1st session, 2012
Receiving laboratory: The Sainsbury Laboratory (SLCU), University of Cambridge, Cambridge, UK
Country of origin : France
MECHANICAL CHANGES PREDICTING LEAF SHAPE STUDIED THROUGH 3D ATOMIC FORCE MECHANICAL IMAGING
I take the opportunity of my stay in Cambridge to address the complexity of leaf growth, which is a complex 4D question. Our previous results demonstrate that the understanding of this system will require a total 3D mechanical imaging of the leaf from the tissue to the subcellular level. We have demonstrated that this could be achieved using Atomic Force Microscope (AFM) mechanical imaging and different shapes and intensities of indentation. There are three main features of leaf shape that we will address a) mechanical control of the leaf blade growth b) mechanics of leaf lobe formation c) how integrated is the vein cell growth into the whole tissue growth. These questions are all complex and have always been asked separately. The biomechanic approach we will use will address the three questions simultaneously. Using the huge available genetic tools (mutant, gene overexpressor) we plan to pinpoint the characteristics of each events and their mechanic relations.
Microscopic appearance (top) and scanning atomic force microscope images (bottom) of guard cells and their surrounding pavement cells from the leaf epidermis of Arabidopsis plants. The left images are wild-type plants, the right ones over expressing pectin methyl esterase, which reduces the elastic modulus of the cell wall, and affects guard cell behaviour.
My research is aimed at understanding the mechanism of plant morphogenesis and its regulation using a multi-disciplinary approach. Most of my work was focused on the genetic and mechanic control of organ formation: phyllotaxis. More recently I have worked on tissue anisotropic expansion. My PhD, completed at INRA Versailles under the supervision of Patrick Laufs was focused on transcription factor and microRNA regulation of meristem function in plants. As a postdoctoral fellow, I worked both in the department of physics at Paris VII, in the laboratory of Yves Couder, designing an AFM derived mechanical imaging, and in Hermann Höfte lab in Versailles to study a new cell wall chemical regulation of organ formation. Finally, as a researcher at INRA, in the laboratory of Hermann Höfte, I continue this approach working as a detached scientist in the MSC physics laboratory (Matière et Systèmes Complexes) at Paris VII. During this last year I also worked on trying to develop applied novel technologies based on my discovered properties of plant growth. This has led to two patents in France: one on a new type of plant protective molecule; the other on a driller bioinspired by root.
Sarah Robinson; Agata Burian; Etienne Couturier; Benoit Landrein; Marion Louveaux; Enrique
D. Neumann; Alexis Peaucelle; Alain Weber; Naomi Nakayama
Mechanical control of morphogenesis at the shoot apex
Journal of Experimental Botany 2013; doi: 10.1093/jxb/ert199
Siobhan A. Braybrook and Alexis Peaucelle
Mechano-chemical feedback underlies organ formation
Plos One 2013 Mar 12 (PLoS ONE 8(3): e57813. doi:10.1371/journal.pone.0057813)
Cell wall mechanics and growth control in plants: the role of pectins revisited
Frontiers In plants physiology 2012
Siobhan A Braybrook; Herman Hofte; Alexis Peaucelle
Probing the mechanical contributions of the pectin matrix: insights
for cell growth. Plant Signaling and Behavior 2012.
Uyttewaal M, Burian A, Alim K, Landrein B, Borowska-Wykręt D, Dedieu A, Peaucelle A, Ludynia M, Traas J, Boudaoud A, Kwiatkowska D, Hamant O.
Mechanical stress acts via katanin to amplify differences in growth rate between adjacent cells in Arabidopsis. Cell. 2012 Apr 13;149(2):439-51
Peaucelle A, Braybrook SA, Le Guillou L, Bron E, Kuhlemeier C and Höfte H.
Curr Biol. 2011 Oct 25;21(20):1720-6.
Peaucelle A, Louvet R, Johansen JN, Salsac F, Morin H, Fournet F, Gillet F, Höfte H, Laufs P, Mouille G and Pelloux J.
Transcription factor BELLRINGER modulates phyllotaxis by regulating the expression of a pectin methylesterase in Arabidopsis. Development. 2011 Nov;138(21):4733-41.
Laufs P, Peaucelle A, Höfte H.
Shaping the meristem by mechanical forces.
F1000 Biology Reports 2009, 1:45
Peaucelle A, Louvet R, Johansen JN, Höfte H, Laufs P, Pelloux J, Mouille G.
Arabidopsis phyllotaxis is controlled by the methyl-esterification status of cell-wall pectins.
Curr Biol. 2008 Dec 23.
Raman S, Greb T, Peaucelle A, Blein T, Laufs P, Theres K.
Interplay of miR164, CUP-SHAPED COTYLEDON genes and LATERAL SUPPRESSOR controls axillary meristem formation in Arabidopsis thaliana.
Plant J. 2008 Jul
Peaucelle A and Patrick Laufs
Phyllotaxy : beyond the meristem and auxin comes the miRNA
Plant Signal Behav. 2007 Jul
Peaucelle A, Morin H, Traas J, Laufs P.
Plants expressing a miR164-resistant CUC2 gene reveal the importance of postmeristematic
maintenance of phyllotaxy in Arabidopsis
Development. 2007 Jan 24
Nikovics K, Blein T, Peaucelle A, Ishida T, Morin H, Aida M, Laufs P.
The Balance between the MIR164A and CUC2 Genes Controls Leaf Margin Serration in Arabidopsis.
Plant Cell. 2006 Nov 10
Peaucelle A, Laufs P.
The UN peace-keeping force in the plants: A microRNA, miR164, stabilizes the boundary domain in the meristem
Med Sci (Paris). 2006 Oct;22(10):796-8. Revu.
Carraro N, Peaucelle A, Laufs P, Traas J.
Cell differentiation and organ initiation at the shoot apical meristem.
Plant Mol Biol. 2006 Apr;60(6):811-26. Revu.
Laufs P, Peaucelle A, Morin H, Traas J.
MicroRNA regulation of the CUC genes is required for boundary size control in Arabidopsis meristems.
Development. 2004 Sep;131(17):4311-22.
Peaucelle A, Deveaux Y , Roberts GR, Coen E, Simon R, Mizukami Y, Traas J, Murray JA, Doonan JH, Laufs P.
The ethanol switch: a tool for tissue-specific gene induction during plant development.
Plant J. 2003 Dec;36(6):918-30.