From the inside out: how internal growth controls anther morphology

This seminar is co-sponsored by the University of Pennsylvania's Center for Engineering MechanoBiology, and the Huck Institutes of the Life Sciences' Plant Biology Program.

Abstract:
Coordination of growth between tissue layers is necessary for proper organ development in multicellular organisms. In plants, the differential growth between connected tissues generates “mechanical conflicts” which are believed to regulate 3D organ shape. However, the growth patterns and the role of different tissue layers during this process are still unclear. We use the anther – the floral male reproductive organ – as a model system to investigate this question. Combining live-imaging, 3D growth analysis, genetics, and mechanical modeling, we show that localized fast growth in internal cell layers drives the initiation and outgrowth of the lobes, while generating tension in the epidermal layer. Based on modeling, we propose the concept of “tissue mechanical density”, encapsulating different cellular factors that can trigger such differential growth in plants. We demonstrate experimentally which among these factors is essential for the rapid growth of internal cells driving lobe formation. Finally, we show that at later stages the subepidermal layer (endothecium) exhibits similar growth patterns to the epidermis, reflecting a transfer of tensile stress from the epidermal layer and contributing to the proper shaping of the lobes. Our data reveal how mechanical interactions between distinct tissue layers control 3D morphogenesis.

About the Speaker:
Dr. Anne-Lise Routier-Kierzkowska is an Assistant Professor in the department of Biological Sciences at the Institut de Recherche en Biologie Végétale (IRBV) at the Université de Montréal, Canada. The Routier Lab investigates cell biophysics with the goal of understanding how plant cells use physical forces to control their growth and respond to their environment. The lab is highly interdisciplinary, combining biophysics experiments, live microscopy, 3D image analysis and computational modeling.

Contact

Charles Anderson
cta3@psu.edu