Research in the department of Molecular Evolution (AG Knoop) at the IZMB focuses on the following areas:

Molecular evolution of mitochondrial DNA in early land plants
The mitochondrial DNA (mtDNA) in plants encodes more genes than in animals. More importantly, the plant mtDNAs are characterized by many oddities such as introns, trans-splicing, frequent recombination, foreign DNA inserts from the chloroplast and nuclear genomes, RNA editing and an ongoing gene transfer to the nucleus. We investigate the molecular evolution of these phenomena from a phylogenetic viewpoint focussing on the evolutionary oldest groups of land plants: the bryophyte clades of liverworts, mosses and hornworts and the early tracheophyte clades of lycophytes, ferns and gymnosperms. In the latter groups in particular we are in the process of sequencing complete mtDNAs from three selected plant taxa (in co-operation with AG Prof. Bernd Weisshaar, Bielefeld).

A gene family of membrane proteins involved in transport of magnesium – the AtMRS2 gene family in Arabidopsis thaliana
This project line deals with a plant gene family of membrane proteins (~10 genes conserved across phylogenetically distant plants species) with two transmembrane (TM) domains with the apparent main function of mediating magnesium transport across biological membranes. These proteins are characterized by a highly conserved GMN tripeptide motif behind the first TM domain and we thus named them 2-TM-GMN proteins. They are ubiquitously present in all domains of life including eukaryotes, archaea and eubacteria, but diversified into gene families only in the plant lineage. The functional transporter in the membrane is a pentamer. Our own experimental investigations include physiological analyses of KO- and overexpressing plant lines, reporter gene studies to analyze protein targeting and tissue-specific expression and protein-protein interaction studies.

The DYW-type of PPR proteins in early land plants with a focus on the model moss Physcomitrella patens
The enigmatic phenomenon of RNA editing in land plant organelles (site-directed pyrimidine exchanges in transcripts) appears to correlate with the presence of a specific subclade of the RNA-binding PPR proteins. PPR proteins are named after the occurrence of Pentatricopeptide Repeat sequence motifs which are encoded by vastly extended gene families with more than 400 members in flowering plants. In particular, we investigate a plant-specific subclade of PPR proteins which are characterized by a unique carboxyterminal extension ending in the DYW tripeptide motif, the presence of which appears to clearly correlate with the occurrence of RNA editing among the earliest land plants (initiated in co-operation with the group of Ian Small, now Perth, Australia).

For further information see our list of publications.