brcamResearch on Plant Fungi Interactions (PFIs) was initiated in the early 1990s with an extensive screening for novel antimicrobial plant peptides, and resulted in the discovery of several types of novel antifungal proteins. On one of them, named the plant defensins (PDFs), pioneering research was continued. PDFs are small, basic, cysteine-rich antifungal peptides that are structurally related to insect and mammalian defensins. They are active against a broad range of phytopathogenic fungi (e.g. Botrytis cinerea, Fusarium spp., Alternaria spp.) and even human pathogens (e.g. Candida albicans and Aspergillus flavus), whereas they are nontoxic to plant and mammalian cells. Primarily based on PDF studies, research on PFIs was further developed in the late 1990s in two closely collaborating research units, focused on each side of the plant-fungus interaction, being the Plant Unit and the Fungus/Yeast Unit, respectively. Only the first unit is associated to the VIB Department of PSB and as such further described below. The Fungus/Yeast Unit studies the mode of action of bioactive peptides (including PDFs) and small molecules, and uses yeast platforms as model systems for higher eukaryotes.

In our Plant Unit, the discovery of different types of PDFs in Arabidopsis thaliana has significantly stimulated our research on their expression and function. For example, the discovery of the plant defensin AtPDF1.2a and the corresponding signaling pathways involved in its induction broadened the general insight in induced defense mechanisms in plants. The corresponding gene is now world-wide used as a marker for ethylene/jasmonate controlled responses in plants. To support this research, different molecular tools and approaches have also been developed optimizing plant transformation and molecular breeding.

Current research is still focussing on (> 320) PDF-like peptides in Arabidopsis using genome-wide approaches, such as the RNAseq technology, primarily aiming at discovering their in planta role. This research is recently broadened to other types of stress-induced peptides (SIPs). Our expertise on resistance mechanisms, mainly in A. thaliana and focusing on resistance to necroptrophic fungi, allowed us to successfully use this model plant as a source of resistance traits against agronomically important crops/diseases (e.g. Botrytis cinerea in tomato, Fusarium oxysporum in banana, Cercospora beticola in sugarbeet, Cochliobolus heterostrophus in corn). Based on the same expertise some years ago, we also initiated research on defense mechanisms induced by biocontrol organisms, the so-called induced systemic response (ISR). This research is based on transcriptome studies both in a model plant (A. thaliana) and in crops (e.g. tomato, lettuce), involves both biotic and abiotic biocontrol agents and is mainly directed to different necroptrophic pathogens.

Bruno Cammue is a visiting PI (10%) at PSB.

For a full overview of his research projects including fungus and yeast research, please refer to: