Differential growth regulation in plants

• Applicant: Dr. Christian Löfke
• Subject Area: Plant Cell and Developmental Biology
• Term: from 2012 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 231641679

The phytohormone auxin has outstanding importance for asymmetric growth regulation, ultimately controlling plant architecture. However, plant growth regulation is poorly understood. To date, systematic analysis of phytohormonal crosstalk for cellular growth regulation is missing.Here we propose to use root epidermal cells as a model system to systematically address auxin regulated cellular division, elongation and differentiation events. Root epidermal cells are regularly spaced in root hair (trichoblast) and non-hair (atrichoblast) cells. The first visible differences between tricho- and atrichoblast cells are already detectable in the meristematic region, where trichoblast cells show a more intense cytoplasmic staining, shorter cells that undergo a higher rate of cell division, and a delay in vacuolization relative to cell elongation. Beside the differential growth behavior, root epidermal cells are accessible for super resolution imaging techniques and moreover have outstanding developmental importance for root-soil interface formation, root organ size determination and gravitropic growth responses. Hence, trichoblast/atrichoblast specification represents an applicable model for cell size regulation. We propose to use epidermal root cells as a suitable model system to unravel auxin dependent differential growth regulation. Notably, root hair signaling mutants displaying either only tricho- or only atrichoblast development show hypersensitive and resistant root growth when treated with auxin, respectively. We will particularly focus on the auxin-dependent regulation of vacuolar biogenesis and its importance in turgor driven cell expansion. This systematic approach, using genetic, pharmacological, transcriptom and defined live cell imaging tools, will provide novel insight into plant specific regulation of cellular growth.

• DFG Programme: Research Fellowships
• International Connection: Austria
• Host: Professor Dr. Jürgen Kleine-Vehn