Effector proteins cause disease! How do they do it?

We have recently shown that S. nodorum produces proteins (knownn as effectors) that have a significant role in causing disease. These proteins appear to be secreted by the fungus during the very early stages of infection and internalised within the wheat host cells. Inside the host cells, the proteins then interact with the wheat host via a gene-for-gene interaction by an as yet undetermined undergo a  with corresponding host genes which results in disease. The molecular basis of this interaction is unknown. Studies to date with collaborators have identified three host specific toxins, ToxA, Tox1 and Tox3.

Multiple projects are available in the following areas to study these effector proteins further (skills gained in these projects are shown in brackets);

1. How does wheat respond to the effector protein exposure at the transcript level? (RNA isolation, RNA sequencing, bioinformatics)
2. How are these effector proteins regulated? The genes encoding these effector proteins are only expressed either during infection or under very specific in vitro conditions. Why? (Molecular biology, promoter analysis using GFP fusions, genetic modification techniques)
3. Localisation of the effector proteins during infection. Where do the effector proteins go during infection? This can be monitored using confocal microscopy and fluorescence. (confocal microscopy, mircoscopy sample preparation techniques, molecualr biology)
4. Do the pathogen effector proteins bind to wheat proteins during infection? (yeast 2-hybrid analysis, co-immunoprecipitation, molecular biology)

Papers to emerge from this project include:

• Du Fall, L.A. & Solomon, P.S. (2013) The necrotrophic effector SnToxA induces the synthesis of a novel phytoalexin in wheat. New Phytologist (in press).
• Vincent D., Du Fall L.A., Livk A., Mathesius U., Lipscombe R.J., Oliver R.P., Friesen T.L. & Solomon P.S. (2012) A functional genomics approach to dissect the mode of action of the Stagonospora nodorum effector protein SnToxA in wheat. Molecular Plant Pathology 13, 467-482.
• Liu, Z., Zhang, Z., Faris, J.D., Oliver, R.P., Syme, R., McDonald, M.C., McDonald, B.A., Solomon, P.S., Lu, S., Shelver, W.L., Xu, S. & Friesen, T.L. (2012) The cysteine rich necrotrophic effector SnTox1 produced by Stagonospora nodorum triggers susceptibility of wheat lines harboring Snn1. PLoS Pathogens 8, e1002467.
• Oliver, R.P. & Solomon, P.S. (2010) New developments in pathogenicity and virulence of necrotrophs. Current Opinion in Plant Biology 13, 415-410.
• Liu, Z., Faris, J.D., Oliver, R.P., Tan, K-C., Solomon, P.S., McDonald, M.C. McDonald, B.A., Nunez, A., Lu, S., Rasmussen, J.B. & Friesen,, T.L. (2009) SnTox3 acts in effector triggered susceptibility to induce disease on wheat carrying the Snn3 gene. PLoS Pathogens 5, e1000581.
• Liu, Z., Friesen, T.L., Stukenbrock, E.H., Meinhardt, S., Ling, H., Faris, J.D., Rasmussen, J.B., Solomon, P.S., McDonald, B.A., and Oliver, R.P. (2006) Horizontal transfer of a fungal virulence gene controlling host specificity. Nature Genetics 38, 953-956.

Lab members involved in this project: Dr Britta Winterberg, Dr Susan Breen, Lauren Du Fall