Scientist (f/m) / PhD position Quantitative analysis of the cellular growth dynamics during lateral plant growth
Lateral growth of plant shoots and roots is based on the activity of a group of stem cells, the cambium, and essential for generating large plant bodies. Thereby, it substantially contributes to the dominance of seed plants in terrestrial ecosystems, to wood formation and thus to carbon immobilization. In addition, the process represents a striking example for a constant remodeling of adult body structures without impairing their actual function. Thus, lateral growth provides excellent opportunities for addressing the fundamental question of how cellular properties are integrated and adapted during the growth of adult organisms and how postembryonic growth processes integrate constraints of the existing body. Importantly, because the overall shape of plant growth axes stays cylindrical during their lateral expansion, the process provides the unique opportunity to analyse growth without having to consider the change of organ shape. Another unique feature is that organ expansion happens exclusively in lateral orientation implying that a 2-dimensional view on plant growth axes is sufficient for a meaningful characterization. Importantly, the process has been described histologically, but a systemic model implementing physical and developmental interactions in a quantitative manner is pending. In this project, we will employ a combination of computational modelling, informative tissue marker lines, mutants affected in cambium activity and Brillouin spectroscopy to establish a quantitative model of lateral plant growth taking into consideration both physical and developmental constraints. Importantly, the power of the established models to predict the role of decisive parameters will be tested by quantitatively comparing lateral growth in Arabidopsis thaliana and Cardamine hirsuta. In case of being instructive, predictions made by the model will be tested molecularly in comparative approaches. Following this strategy, our project will provide insight into the cellular, genetic, and physical cues that are involved in the regulation of the growth of mature plant organs using a rather simple morphodynamic system.

References: Elsayad K, Werner S, Gallemi M, Guajardo ERS, Zhang L, Jaillais Y, Greb T, Belkhadir Y (2016) Correlative 3D mapping of high-frequency mechanical properties of the extracellular matrix in live plant cells. Sci Signal 9(435):RS5. Greb T, Lohmann JU (2016) Plant Stem Cells. Curr Biol 26(17):R816-R821. Sanchez P, Nehlin L, Greb T (2012) From thin to thick – major transitions during stem development. Trends Plant Sci 17:113-121. Merks RM, Guravage MA. (2013) Building simulation models of developing plant organs using VirtualLeaf. Methods Mol Biol. 959:333-52. Methods that will be used: Brillouin spectroscopy Computational Modelling (VirtualLEaf) Histology Confocal microscopy Image Analysis (Ilastik) Cooperation partners: The DFG consortium ‘Morphodynamics in Plants’ consisting of the groups of Fred Hamprecht (Heidelberg University), Karen Alim (MPI Göttingen), Jan Lohmann (Heidelberg University), Angela Hay (MPI Cologne), Kay Schneitz (TUM Munich), Miltos Tsiantis (MPI Cologne), Richard Smith (MPI Cologne), Alexis Maizel (Heidelberg University)


Personal qualifications: The ideal candidate should be willing to learn and establish novel technologies and be interested in quantitative aspects of developmental processes and in evolution. A background in molecular biology, imaging, image analysis or computational modelling would be desirable. He/she should also be able to work independently as well as in a team, be well organised and prepared to work in an international environment. Good interpersonal communication skills are essential.


Deadline: 30. Jun 2017


Contact details: Greb, Thomas