Plant defence responses and resistance mechanisms

The role of phytohormone signalling pathways (ethylene, jasmonate) in the interaction of Botrytis cinerea with tomato was studied. Several Arabidopsis mutants were tested for susceptibility to three Botrytis species (Botrytis cinerea, Botrytis tulipae and Botrytis elliptica) and cellular processes leading to successful infection or resistance were analysed using histochemical stains and pharmacological inhibitors. The general picture emerges that it is crucial for Botrytis species to cause programmed cell death in the host, in order to achieve successful infection.

A quantitative disease assay on leaves and stem segments allowed to identify wild relatives of tomato (Solanum spp.) that provide a source of genetically determined (partial) resistance to Botrytis cinerea. We managed to introgress 10 quantitative resistance loci from Solanum habrochaites and 3 from Solanum neorickii into cultivated tomato.

Plants contain proteins that may inhibit fungal endopolygalacturonases, so-called PGIPs. In collaboration with other labs, we were the first to demonstrate the potential of PGIPs to confer partial resistance to Botrytis cinerea. We demonstrated that the interaction between PGIPs and endoPGs in planta is more complex than one would anticipate from in vitro studies. The current research focuses on the Arabidopsis locus RBPG1, controlling the response to B. cinerea endopolygalacturonases, and the potential role of this gene in resistance mechanisms against microbial pathogens