How does the fungal pathogen Zymoseptoria tritici cause disease on wheat?

This is one of the funded projects for our 2025 Undergraduate vacation bursary, click here to return to the list of 15 projects.

This project is going to be…	Experimental (lab/field based)
Institute	The Australian National University
Project supervisor	Dr. Erin Hill
Title of Project	How does the fungal pathogen Zymoseptoria tritici cause disease on wheat?
Date of Project Commencement	19 May 2025
Duration (weeks)	8
Brief Description of Project	Zymoseptoria tritici is a highly destructive wheat pathogen that significantly reduces yields worldwide, including in the UK, Europe, and Australia. Over the past decade, intense research efforts have advanced our understanding of this disease, particularly through the identification of avirulence (Avr) genes in the pathogen and resistance (R) genes in the host.Avirulence genes identified in Z. tritici typically encode small, cysteine-rich proteins (e.g., Avr3D1 and AvrStb6) of unknown function, with one notable exception being a protease (AvrStb9). These Avr genes are recognized by corresponding host R genes, triggering a defence response that restricts pathogen growth. While these genes have evolved mechanisms to evade recognition, they are often retained in the pathogen, suggesting they play a critical role in its pathogenicity. Despite considerable progress, the specific functions of these proteins in disease development remain poorly understood. On the host side, two wheat R genes have been cloned in recent years: Stb6, which recognizes AvrStb6, and Stb16q, which interacts (directly or indirectly) with AvrStb16q (yet to be cloned). Unlike many R genes that confer resistance to biotrophic pathogens like rusts and mildews, Stb6 and Stb16q encode receptor-like kinases, which likely detect pathogen signals outside the cell. However, the exact nature of these signals and whether the R proteins directly interact with their cognate Avr proteins remain unresolved.This project offers the opportunity to explore the molecular interactions between Z. tritici and wheat by employing a range of techniques. Students will gain hands-on experience in reverse genetics, protein expression, protein interaction assays, and various molecular and biochemical methods. By the end of the project, participants will develop a solid understanding of these methodologies and the molecular basis of plant-pathogen interactions. Additionally, the work will be conducted in a well-resourced laboratory, collaborating with a diverse team of students and postdoctoral researchers from around the globe, all dedicated to advancing our understanding of plant diseases. Recommended reading for the projectSaintenac, C., W.-S. Lee, F. Cambon, J. J. Rudd, R. C. King, W. Marande, S. J. Powers, H. Bergès, A. L. Phillips, C. Uauy, K. E. Hammond-Kosack, T. Langin and K. Kanyuka (2018). “Wheat receptor-kinase-like protein Stb6 controls gene-for-gene resistance to fungal pathogen Zymoseptoria tritici.” Nature Genetics 50(3): 368-374. Zhong, Z., T. C. Marcel, F. E. Hartmann, X. Ma, C. Plissonneau, M. Zala, A. Ducasse, J. Confais, J. Compain, N. Lapalu, J. Amselem, B. A. McDonald, D. Croll and J. Palma-Guerrero (2017). “A small secreted protein in Zymoseptoria tritici is responsible for avirulence on wheat cultivars carrying the Stb6 resistance gene.” New Phytol 214(2): 619-631.Amezrou, R., C. Audéon, J. Compain, S. Gélisse, A. Ducasse, C. Saintenac, N. Lapalu, C. Louet, S. Orford, D. Croll, J. Amselem, S. Fillinger and T. C. Marcel (2023). “A secreted protease-like protein in Zymoseptoria tritici is responsible for avirulence on Stb9 resistance gene in wheat.” PLoS Pathog 19(5): e1011376. Alassimone, J., C. Praz, C. Lorrain, A. De Francesco, C. Carrasco-López, L. Faino, Z. Shen, L. Meile and A. Sánchez-Vallet (2024). “The Zymoseptoria tritici Avirulence Factor AvrStb6 Accumulates in Hyphae Close to Stomata and Triggers a Wheat Defense Response Hindering Fungal Penetration.” Mol Plant Microbe Interact 37(5): 432-444.