Understanding the ancestral function of RCO/LMI1 type homeobox genes in early-divergent land plants.

• Applicant: Professor Dr. Miltos Tsiantis
• Subject Area: Evolution and Systematics of Plants and Fungi ; Plant Genetics and Genomics ; Plant Cell and Developmental Biology
• Term: from 2020 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 440144334

We have recently shown that homeodomain transcription factors of the Late Meristem Identity 1 (LMI1) / Reduced Complexity (RCO) type participate in a novel growth regulating pathway that underlies evolutionary diversification of leaf form in seed plants. Together with Prof. Sabine Zachgo, we have also obtained preliminary evidence that an LMI1 type gene regulates growth in the liverwort Marchantia polymorpha. These findings lead to the hypothesis that at least some aspects of this pathway may operate in liverworts and therefore may represent deeply conserved functions that were important for early land plant evolution. To test this hypothesis, we propose to characterize the function of LMI1 type genes in the model Marchantia polymorpha using genetics, advanced imaging and computational modelling. We also propose to investigate functions of this transcription factor in the model moss Physchomitrella patens which will help pinpoint if aspects of LMI1 type gene function in growth regulation were conserved in early land plants. Finally, through targeted transgenic experiments with related sequences from green algae, we will aim to investigate whether structural features of the protein necessary for growth regulation were already present before plants colonized land and therefore may have enabled this colonization.

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