Evolution of novel RHO OF PLANTS signalling activators during the adaptation from water to land.

• Applicant: Dr. Philipp Denninger
• Subject Area: Plant Cell and Developmental Biology ; Evolution and Systematics of Plants and Fungi
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 528090862

Terrestrialization of plants was a key evolutionary process to for the transformation of the earth's surface as we know it today. To thrive on land, plants needed to adapt to terrestrial conditions, which majorly differ from submerged habitats in salt or fresh water. Land plants evolved in freshwater ponds from streptophyte algae and different from algae in submerged habitats, land plants needed to develop specialised tissues and cells to achieve this conquest of land. Here, we propose a project that will contribute to the MAdLand mission to understand which molecular features enabled streptophyte algae for terrestrialization, and which characteristics allowed the last common ancestor of land plants and streptophyte algae to start this evolutionary. We investigate ROPGEFs, activators of RhoGTPases signalling, that regulate polar growth and cell differentiation. We find that ROPGEFs are Streptophyta specific and diversified in land plants. This makes ROPGEFs a great model to study how molecular features needed to evolve during the conquest of land. We will use cross-species complementation of Marchantia polymorpha with ROPGEFs of Streptophyte algae to find the evolutionary origin of this protein family. Further, we will use different cell biological techniques, like immunolocalisation, to describe these ROPGEFs in streptophyte algae. Our project will contribute to our knowledge about the nature of the last common ancestor of land plants and streptophyte algae was, and which molecular pathways adapted during the conquest of land.

• DFG Programme: Priority Programmes
• Subproject of: SPP 2237: MAdLand — Molecular Adaptation to Land: plant evolution to change