Moss Systems Biology

Members of the Reski plant biotech lab are working on gene expression in the bryophyte Physcomitrella patens (Hedw.) B.S.G. at different levels in correlation with phenotype analysis. We study

  • transcripts
  • proteins
  • protein-modifications
  • metabolites
  • sub-cellular integration
  • and employ comparative genomics approaches

to reveal ......

Unique Genetic Features

To date, the moss Physcomitrella patens is the only known terrestrial plant with an efficient system for homologous recombination in its nuclear DNA. This makes gene targeting strategies as easy as in yeast.

At the same time, bryophytes are the oldest living branch in land plant evolution, separated by approx. 450 million years of evolution from seed plants like Arabidopsis thaliana. To fully understand (and employ) land plant evolution and plant diversity, mosses are to be added to the current list of model plants.

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In contrast to seed plants, the dominating generation in the moss life cycle is the haploid gametophyte. Gene/function-correlations can therefore be readily established by use of loss-of-function mutants (created by targeted gene knock-out) without complex back-crosses.

Moss development starts with a filamentous tissue, the protonema, which is growing by apical cell division and, therefore, represents a perfect cell-lineage. In moss protonema, plant development can be pinpointed to the differentiation of a single cell.

As every cell of the moss protonema is in close contact with its environment, this system is amenable to advanced, non-invasive cell biological techniques.

The basal cell type, the chloronema cell, has four different fates: Besides self-replication it can differentiate into tmema cells, caulonema cells, and three-faced apical cells (buds). Cell replication and differentiation are highly regulated at different levels of function by cross-talks between stimuli like light, nutrients, and hormones.

Aims and Objectives

Our vision is to fully unravel the complex regulatory networks underlying these developmental decisions. This is a long-term goal, making it necessary to combine different levels of function, obtain quantitative biological data, preferably from the single cell level, model networks in the computer and make predictions for novel biological experiments.

Such a holistic strategy on plant development combines biology, tools for micro analysis, computational biology and modelling, and is called "Systems Biology".

Homologous Recombination

To date the moss Physcomitrella patens (Hedw.) B.S.G. is the only terrestrial plant with an efficient system for homologous recombination in its nuclear DNA.

Functions of Genes

We apply this technique in order to analyse the function of novel genes by gene knockout and by allele replacement, and, furthermore, try to understand why homologous recombination in Physcomitrella is about five orders of magnitude more efficient than, for example, in Arabidopsis.

Transfer of such principles to crop plants would have a great biotechnological impact, drastically improving the ways transgenic crops are produced. This in turn may help to get better public acceptance for transgenic plants.


In close cooperation with industrial partners we initiated functional genomics of Physcomitrella, identifying novel genes relevant to metabolic engineering and to abiotic stresses such as drought, salt and cold. Such moss genes are being directly transferred to crop plants to improve their performance.

Transgenic Physcomitrella can be grown photoautotrophically in bioreactors. We work on the production of pharmaceutically relevant proteins in such cultures in co-operation with the university spin-off company greenovation Biotech, Freiburg.

In addition to these successful industrial co-operations we are ready to establish new partnerships.
As a university group our work is primarily science-driven. However, we strongly feel that our basic work is paid by tax-money and we, therefore, have the responsibility to transfer applicable know-how swiftly to the market.

Publications and Patents

Please screen our publications and patents. Most papers can easily be downloaded from this site as pdf files.