PhD Position - Spatio-temporal Specificity of Cambium Stem Cell Signaling
Description:

Lateral growth of plant shoots and roots is essential for the formation of wood and of large plant bodies, and thus for the creation of biomass on earth. The process depends on the tissue-forming properties of a group of stem cells called the cambium, the activity of which leads to the production of secondary vascular tissue (wood and bast). Here, we want to leverage the unique features of the cambium and establish general principles of stem cell niche organization in plants and beyond by revealing spatio-temporal interfaces of two hormonal signaling pathways fundamental for cambium activity: auxin and cytokinin signaling. Based on our recent findings that auxin signaling influences components of the cytokinin biosynthesis machinery in cambium cells, we hypothesize that this crosstalk and the accompanying intercellular signaling network is essential for cambium organization and activity. In this project we will test this hypothesis by tissue-specific modulation of cytokinin signaling and of auxin and cytokinin biosynthesis and their respective movements from cell to cell. Furthermore, elucidating the activity domains of crucial signaling factors in the cambium area will reveal the spatial organization of auxin and cytokinin signaling in this least-explored indeterminate plant stem cell niche. The project is embedded into the Collaborative Research Center SFB 873 “Maintenance and Differentiation of Stem Cells in Development and Disease” located at Heidelberg University.

References:  Jouannet V, Brackmann K, Greb T (2015) (Pro)cambium formation and proliferation: two sides of the same coin? Current Opinion in Plant Biology 23:54–60.

Agusti J, Lichtenberger R, Schwarz M, Nehlin L, Greb T (2011) Characterization of transcriptome remodeling during cambium formation identifies MOL1 and RUL1 as opposing regulators of secondary growth. PLoS Genet 7:e1001312.

De Rybel et al. (2014) Integration of growth and patterning during vascular tissue formation in Arabidopsis. Science 345: 6197

Methods that will be used are the generation of transgenic plant lines enabling induction of tissue-specific modulation of hormonal signalling and tissue-specific transcriptional profiling. Spatio-temporal organization of signalling cascades will be explored by state-of-the-art confocal microscopy and reverse genetics. In addition to the intensive exposure to a comprehensive spectrum of molecular, microscopic and genetic methods, the student will get the opportunity for the in silico analysis of RNAseq-derived data and - potentially - for computational modelling of signalling networks.

 

Cooperation partners:  Jan Lohmann, Centre for Organismal Studies, Heidelberg, Germany

Dolf Weijers, University of Wageningen, Netherlands

 

Deadline: 31st Dec 2015    Start date: 1st Feb 2016

Applicant profile: The ideal candidate should be willing to learn and establish novel technologies and be interested in biological aspects of microscopic analyses of multicellular samples. 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.

Please apply through the HBIGS site at Heidelberg University (http://www.hbigs.uni-heidelberg.de).

Contact details: Dr. Thomas Greb, thomas.greb [ aT ] cos.uni-heidelberg.de