The Team
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Unit of Plant Molecular Cell Biology

Research overview

Our research activities are mainly devoted to study cell biological phenomena in the context of plant-microbe interactions. In particular, we focus on the interactions between plants and powdery mildew fungi, obligate biotrophic ascomycetes that cause agronomically relevant  diseases (Figure 1). One of our major interests is to unravel the cellular mechanisms of plant defence, but we are also interested in the molecular details of fungal pathogenicity.

Our lab employs a mixture of molecular biology, cell biology, biochemistry, plant genetics and fungal genomics to pursue these goals. The main plant species used in our research projects are the dicotyledonous reference species, Arabidopsis thaliana, and the monocotyledonous cereal, barley (Hordeum vulgare). Accordingly, on the fungal side emphasis is given to powdery mildew species colonizing barley (Blumeria hordei) and Arabidopsis (Erysiphe cruciferarum).

Current research projects comprise the following:

1. Host plant research

Mechanism of mlo resistance and pleiotropic phenotypes

Loss of MLO protein function leads to broad-spectrum resistance against powdery mildew. Our research focuses on identifying the underlying mechanism. In barley and Arabidopsis, the mlo mutations are accompanied by negative side effects, so-called pleiotropic phenotypes. Although those phenotypes have been first described over 30 years ago, their molecular basis remains unknown. We work on unravelling the mechanism behind those unwanted side-effects.

2. Barley–B. hordei interaction

Cross-kingdom communication and effector biology

Plants and microbes exchange different types of molecules to manipulate cellular processes in the interacting organism. We study the exchange of small non-coding RNAs, such as miRNAs and rRNA- or tRNA-fragments in the barley-B. hordeiB. hordei and work on revealing interacting proteins and their mode of action in the barley-B. hordei interaction and further explore the role of extracellular vesicles in their transport. Moreover, we are interested in the effector repertoire of B. hordei and work on revealing interacting proteins and their mode of action in barley.

3. Arabidopsis–E. cruciferarum interaction

MLO and EXO70 interplay in focal secretion

Some isoforms of membrane-resident MLO proteins confer resistance to the fungal powdery mildew disease, whereas EXO70 proteins are subunits of the exocyst complex, which is involved in exocytic vesicle tethering. We found an isoform-preferential interaction of MLO and EXO70 proteins. Based on this interaction, we are investigating how MLO and EXO70 proteins interplay in focal secretion.

4. Powdery mildew research

Powdery mildew genomics

Our research focuses on understanding how fungal powdery mildew pathogens co-evolve with their host plants. We use advanced technologies to explore the role of transposable elements in powdery mildew evolution, their impact on fungal genomes, and how they are regulated to prevent genome damage. One of our key findings was that transposable elements are induced at specific infection stages, and that they give rise to novel long noncoding RNAs. We are uncovering how these long noncoding RNAs contribute to transposon regulation and gene invention in B. hordei.

Useful links

A general introduction to the Arabidopsis-powdery mildew interaction can be found in
The Arabidopsis Book. A recent update of this chapter can be found here.


Figure 1.
Barley mlo mutants are broad-spectrum resistant to powdery mildew. Phenotype of a susceptible (Mlo , left) and a mlo -resistant (right) barley genotype inoculated with Blumeria graminis f. sp. hordei K1 conidia and photographed at six days after inoculation.

Figure 2.
Epifluorescence micrograph of a barley cell expressing a DsRED-labelled peroxisomal protein. The bright little dots inside the cell mark (mobile) peroxisomes.

Figure 3.
Cell-autonomous complementation of mlo resistance by transient expression of a Mlo cDNA in a epidermal cell of a barley mlo genotype. Note the successful colonization of the transformed beta-glucuronidase marker gene expressing  (greenish) cell as evidenced by the formation of an intracellular haustorium and hyphal growth.

Last updated 11.05.2023