Department Biologie I
Systematische Botanik und Mykologie
Menzinger Str. 67
27, ground floor
Phone: +49 89 17861-302
Fax: +49 89 172638
Wednesdays, 1 - 3 pm
Molecular evolution and diversification of transcription factors
Plants evolved a wide range adaptations to successfully conquer dry land. Several steps from algae to the terrestrial bryophytes were taken to allow the growth and development outside the water, e.g. the development of structures for stabilization or for water and nutrient uptake. In lycopods and ferns specialized leaves for sexual reproduction developed that allowed a long distance dispersal by wind. Flower induction that is widely controlled by the seasonal change in day/night cycles allowed an almost temperature independent sexual reproduction, which matches nicely with the activity of pollinators.
All these developmental processes and necessities are controlled by DNA-binding proteins that must have been present in algae already and diversified in the earliest land plants. While some of these transcription factors are restricted to the land plant phyla, others are found ubiquitous in all eukaryotes or even in bacteria. Few DNA-binding protein families presumably evolved in green algae, shortly before settlement of land. Of special interest are, therefore, transcription factor families that are important for sexual reproduction and during plant stress defense responses.
The genetic model Marchantia polymorpha is a liverwort species that resides phylogenetically at the base of all land plants. Besides Arabidopsis thaliana, rice, barley and tobacco, the applicability of many well established molecular methods makes Marchantia presumably the most important model for functional analyses in early land plant evolution.
Understanding how regulatory factors evolved and diversified provides not only insight into processes such as speciation and adaptation, but also provide valuable information to breeders on possibly economic traits.
We make use of the available genomic sequence information of marine and freshwater green algae, terrestrial bryophytes, lycopods, ferns and the evolutionary advanced gymnosperms or angiosperms, to construct phylogenetic trees. Such trees allow to identify diversification events that gave rise to new or modified functions within a transcription factor family. Subsequently, we can test the DNA-binding capacity of a protein in vitro and can examine, whether a certain diversification led to altered DNA-binding specificities or not.