Assigning functions to the Marchantia polymorpha MpKNX1C gene

• Applicant: Dr. Madlen I. Rast-Somssich
• Subject Area: Plant Cell and Developmental Biology ; Evolution and Systematics of Plants and Fungi ; Plant Genetics and Genomics
• Term: from 2016 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 346427893

All eukaryotes alternate between haploid (1n) and diploid (2n) stages during their life cycles. A defining feature of land plants is that they are multicellular in both generations, while their presumed ancestral green algae (Charophytes) developed multicellularity only in the haploid stage. This alternation of generations facilitated morphological and physiological adaptations to the terrestrial environment and thus had profound impact on land plant evolution. The liverwort Marchantia polymorpha is an ideal model organism to study the genetic basis for the development of the alternation of generations. M. polymorpha is a member of the first diverging lineage of extant land plants and its genetic makeup may therefore be more similar to that of the common ancestor of all land plants. A low genetic redundany in its regulatory gene families, the haploid-dominant life cycle and recent advantages in functional genomics further facilitate genetic analyses. The aim of this project is to elucidate the underlying genetic programs that govern the development of a diploid multicellular generation in the basal land plant M. polymorpha. Previous research has shown that members of the KNOTTED-like homeobox (KNOX) gene family play a pivotal role for sporophyte development in diverse lineages of eukaryotes. Thus, these genes might be crucial for the evolution of the alternation of generations in land plants. The M. polymorpha genome encodes one full length KNOX1 (MpKNX1C) and one KNOX2 (MpKNX2) protein. While MpKNX2 function has been studied in more detail, little is known about the role of MpKNX1C. I therefore propose to initiate a functional characterization of MpKNX1C by determining its expression pattern and characterizing gain-of-function and loss-of-function phenotypes. I will further identify protein interaction partners, and screen for target genes regulated by MpKNX1C activity. Results from these different approaches will allow me to assign specific functions to MpKNX1C, and expand our knowledge on the evolution and diversity of regulatory systems in land plants.

• DFG Programme: Research Fellowships
• International Connection: Australia
• Host: Professor Dr. John L. Bowman