Marc Somssich is interested in signalling dynamics that govern plant development on an individual cell level, in an intact tissue and organ context. He started off by analysing and comparing differential peptide-receptor signalling dynamics involved in plant stem cell or defence pathways (CLAVATA-WUSCHEL or flagellin, respectively), and has since moved on to study signalling events involving the plant cell wall.

The plant cell wall has long been looked at as merely a physical barrier, forming a defensive wall and providing mechanical strength. However, the plant cell wall is also a sensory organ, directly involved in different signalling pathways, connecting the plant cells with each other and their environment. Marc has studied the cell wall’s role in guiding gravitropic growth, and in response to abiotic (saline) stress, and is now focusing on biotic stress. More precisely, he is investigating the plant cell wall as a sensory organ involved in defence signalling events combating infection by the pathogenic fungus Fusarium oxysporum.

Since joining the University of Melbourne, I, err, I mean, Marc has developed a microscopy-based system that allows the live-imaging of the plant’s defence responses, be it changes in gene expression or protein dynamics and localisation, in real-time. These reactions of the plant immune system are typically recorded on a larger scale (whole plant, whole tissue, in vitro assays…), where the cellular details are often lost. The new system allows to distinguish between the responses of individual, neighbouring cells, thereby providing a much needed cellular resolution. Eventually the aim is to describe in detail how, for example, a cell responses that is under acute attack vs. a cell that is ‘warned’ by its neighbours of an impeding attack. Or a cell that is damaged vs. one that can already ‘sense’ the pathogen but is not damaged yet. Also, the system will be used to study the difference in response to a pathogenic F. oxysporum forma vs. a non-pathogenic forma.

More details and images to follow soon(ish).