Dr Christiane Nawrath, MER, Group Leader

Department of Plant Molecular Biology UNIL Biophore Building CH-1015 Lausanne Tel:  +41 21 692 42 56 Fax: +41 21 692 41 95 E-mail: Christiane.Nawrath@unil.ch 2 doctoral students

Research activities :

• Identification and Characterization of genes involved in cuticle formation
  

Research key words :

• Arabidopsis, mutants, cuticle, stresse defense

Link to our web site

The epidermis of the aerial portions of plants is covered with a continuous extracellular layer of hydrophobic material, the cuticle that plays an important role as interface between the plant and its environment. Primarily evolved as transpiration barrier the cuticle protects the plant against various stresses and plays a critical role in organ development. The cuticle consists of two major components, cutin and wax. Cutin, a unique plant biopolyester mainly composed of fatty acid derivatives, is the major structural component of the cuticle. Waxes overlay and impregnate the cutin network.

Even when a number of genes involved in cutin and wax biosynthesis have been recently identified a large number of aspects relating to the formation of cutin still remains to be discovered, including the mechanisms of transport of cutin monomers to the extracellular space, the polymerisation of cutin, the regulation of the well-structured deposition of cutin within the extracellular matrix, as well as the effects of an altered cutin deposition on the development and the physiology of the plant.

Arabidopsis mutants that have a permeable cuticle show often organ fusions and developmental disorders, such as abnormal trichome initiation. In addition, a highly permeable cuticle in Arabidopsis plants leads also to resistance to the fungus Botrytis cinerea. This pathogen causes grey mould disease on many crop plants and is of high agronomic importance. The resistance in cuticle mutants depends on antifungal compounds that are induced by abiotic factors. We isolated two genes involved in cutin formation by the characterization of permeable cuticle (pec) mutants of Arabidopsis that show a strongly facilitated dye uptake. One gene encodes an long-chain acyl CoA synthatase, an enzyme that is essential for the biosynthesis of cutin monomers and the other encodes an ABC-transporter, most likely transporting cutin monomer across the plasma membrane. Other pec mutants are under investigation.

The goal of the project is to identify and characterize genes of Arabidopsis that are involved in the formation of a functional cuticle by a combined approach using molecular biology, genetics, cell biology, biochemistry and physiology.

Representative publications :

• Nawrath C, Curr Opin Plant Biol., 9:281-287, 2006

• Kunst L and Samuels L., Curr Opin Plant Biol. 12:721-727, 2009

• Bessire M, et al.,EMBO J., 26:2158-2168, 2007