Williams Group - Plant structural immunology

Our primary research objective is to understand the molecular basis of the interactions between plant hosts and the microorganisms, particularly fungi, that colonise them.

To do this we use molecular biology, protein biochemistry/biophysics and structural biology approaches.

Our research encompasses two broad themes

Theme 1: Plant immunity receptors - We want to understand how extracellular and intracellular immunity receptors in plants detect and respond to the recognition of effector (virulence) proteins from plant pathogens. This knowledge will be critical to understand the function of these receptors during resistance responses. It will also inform future gene-editing/genetic engineering approaches to manipulate and enhance plant disease resistance.

See publications 10.1073/pnas.1609922113, 10.1126/science.1247357, 10.1126/science.aax1911, 10.1073/pnas.1621248114, 10.1094/MPMI-03-11-0052, 10.1016/j.chom.2019.07.020

Theme 2: Pathogen effector (virulence) proteins - We want to understand how pathogen effector proteins perturb and/or activate defence pathways. To date, we have a poor understanding of effector virulence function, particularly in eukaryotic pathogens. I’m currently tackling this fundamental knowledge gap by studying multiple model and commercially relevant pathosystems.

See publications 10.1111/nph.17128, 10.1111/nph.17516, 10.1101/2020.05.27.120113, 10.1111/tpj.13228, 10.1111/mpp.12385, 10.1016/j.tplants.2017.06.013, 10.1111/mpp.12597

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Postdoctoral Fellow

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Honours Student

ARC Future Fellow


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Selected publications

Theme 1:

  1. Williams SJ, et al (2014). Structural basis for assembly and function of a heterodimeric plant immune receptor. Science. http://science.sciencemag.org/content/344/6181/299
  2. Casey L, et al (2016). The CC domain structure from the wheat stem rust resistance protein Sr33 challenges paradigms for dimerization in plant NLR proteins. PNAS.
  3. Zhang X, et al (2017) Multiple functional self-association interfaces in plant TIR domains. PNAS. http://www.pnas.org/content/114/10/E2046
  4. Williams SJ, et al (2011) An autoactive mutant of the M flax rust resistance protein has a preference for binding ATP, while wild-type M protein has a preference for binding ADP. MPMI, https://apsjournals.apsnet.org/doi/abs/10.1094/MPMI-03-11-0052

Theme 2:

  1. Outram MA, (2021) The crystal structure of SnTox3 from the necrotrophic fungus Parastagonospora nodorum reveals a unique effector fold and provides insight into Snn3 recognition and pro-domain protease processing of fungal effectors. New Phytologist. https://doi.org/10.1111/nph.17516
  2. Sung YC, Outram MA, et al (2021). PR1‐mediated defence via C‐terminal peptide release is targeted by a fungal pathogen effector. New Phytologist. https://doi.org/10.1111/nph.17128
  3. Zhang X, et al (2018) Crystal structure of the Melampsora lini effector AvrP reveals insights into a possible nuclear function and recognition by the flax disease resistance protein P. MPP https://onlinelibrary.wiley.com/doi/abs/10.1111/mpp.12597
  4. Zhang X, et al (2017) Production of small cysteine-rich effector proteins in Escherichia coli for structural and functional studies. MPP. https://onlinelibrary.wiley.com/doi/abs/10.1111/mpp.12385
  5. Breen S, et al (2016) Wheat PR-1 proteins are targeted by necrotrophic pathogen effector proteins. Plant Journal. https://onlinelibrary.wiley.com/doi/abs/10.1111/tpj.13228
  6. Ve T, et al (2013) Structures of the flax-rust effector AvrM reveal insights into the molecular basis of plant-cell entry and effector-triggered immunity. PNAS. http://www.pnas.org/content/110/43/17594

For a full list of publications


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Simon Williams

Story | Thursday 2 August 2018
Simon Williams uses protein biochemistry and structural biology approaches to understand how plant pathogens cause disease and how the plant immune system prevents infection.

PS PhD Exit Seminar - From structure to function: characterising enzymatic effectors from pathogenic fungi

Event | Fri 13 October 2023
Agricultural crop production is continually challenged by plant-pathogenic fungi, jeopardizing global food security. Central to plant-fungal interactions are small proteins called effectors, which can be secreted by pathogens into plant cells to promote disease.

PS Seminar Series - PhD Exit Seminar - Structural investigation of the interaction between SIX effectors and resistance proteins

Event | Wed 30 August 2023
Fungal pathogens are the main causative agents of disease in plants. Fusarium oxysporum is a diverse fungal pathogen able to infect a wide plant host range.

Australian Synthetic Biology Challenge: The Final Showcase

Event | Tue 20 October 2020
National undergraduate synthetic biology challenge.
Recorded seminar - Dr Megan Outram

PS Webinar Series: The crystal structure of SnTox3 from the necrotrophic fungus Parastagonospora nodorum reveals a unique effector fold and insights into Kex2 protease processing of fungal effectors

Event | Wed 24 June 2020
Plant pathogens cause disease through secreted effector proteins, which act to modulate host physiology and promote infection. Often, effector proteins lack sequence identity to proteins of known function, or functional domains, making it impossible to infer function based on sequence alone.