Date: 30th May 2024
Time: 15:15
Title: Mechanical interactions between tissue layers underlie plant morphogenesis
Location: Lecture room B7, Forest Sciences Building, Latokartanonkaari 7-9
Host: Paula Elomaa
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 roles of different tissue layers during this process are still unclear. Here, we use the anther – the floral male reproductive organ – as a model system to investigate this question. Combining live-imaging, 3D growth analysis, osmotic treatment 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. 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 mechanical load stretching the epidermal layer is transferred to the first subepidermal layer (endothecium), contributing to the proper shaping of the anther. Our data reveal how mechanical interactions between tissue layers control 3D morphogenesis.