The following positions are currently open
A PhD position is available in the group of Jan Lohmann to study the interplay between shape and cell fate signaling in the shoot apical meristem.
Shape and activity of the shoot apical meristem (SAM) have a profound influence on plant morphology. Since all above ground organs are directly derived from this stem cell system, regulatory programs controlling cell proliferation and organ initiation are tuned to perform within a set of morphological parameters of the shoot apex. However, neither the role of basic cellular features of the meristem, such as cell number, cell size, or cell wall stiffness, nor the influence of differential cell fate e.g. stem cell fate vs. non-stem cell fate, on shoot morphology have been fully resolved. Using quantitative morphodynamics, we have recently found that environmental parameters, such as ambient temperature or day-length, have a substantial effect on the layout of the apical stem cell system. This influence extends from the basic cellular arrangement within the shoot meristem to the number and localization of stem cells and follows distinct regulatory dynamics, which can be temporally uncoupled. While stem cell identity responds quickly and reversibly to transient perturbations, cell size and number within the shoot apical meristem are fixed within a critical developmental window, allowing us to specifically modify stem cell fate against several stable SAM morphologies within physiological parameters. In addition to short term acclimatization responses to light and temperature, we have also identified substantial morphological and cellular variations in SAMs of Arabidopsis accessions collected from diverse habitats. These accessions also differ in their architectures, suggesting that regulation of SAM layout and morphogenetic processes might be evolutionary linked.
In the framework of the research unit 2581, we will now study the intricate interplay between shape and cell fate signaling in the SAM using an integrated approach build on environmental perturbations, advanced cell type specific genetics, recording of mechanical parameters, multispectral live imaging, as well as mathematical modeling. We expect to identify important regulatory nodes guiding SAM function and shoot morphology, mechanisms underlying the feedback between SAM layout and stem cell activity, including mechanics, as well as their relative contribution to developmental plasticity.
last updated: October 19, 2017