Poster Presentation International Plant Molecular Biology Conference 2024

Zinc-bound effectors in wheat stem rust and exploration of their virulence functions (#201)

Zhao Li 1 , Megan Outram 2 , Shouvik Aditya 1 , Nuren Tasneem 1 , Jana Sperschneider 2 , Michael Kuiper 3 , Melania Figueroa 2 , Peter Dodds 2 , Simon Wiliams 1
  1. The Australian National University, Acton, CANBERRA, ACT, Australia
  2. Agriculture and Food, Commonwealth Scientific and Industrial Research Organisation, , Canberra, ACT, Australia
  3. Data61, Commonwealth Scientific and Industrial Research Organisation, Canberra, ACT, Australia

Crop production is severely impacted by plant pathogens, posing a significant threat to global food security. During infection, pathogens secrete and deliver numerous effector proteins into plant cells to suppress plant immunity and facilitate colonization. Effectors can be recognised by intracellular plant immunity receptors, known as nucleotide-binding/leucine-rich-repeat receptors (NLR), which activate defence response leading to immunity. In this study, we used AlphaFold2 to predict the structural classes of predicted effectors secreted by the wheat stem rust fungus (Puccinia graminis f. sp. tritici). This analysis revealed that some of the largest structural classes of effectors are predicted to bind metals, including the known avirulence effectors AvrSr27, AvrSr22 and AvrSr13. Utilising a series of biochemical assays, including PAR (4-(2-pyridylazo) resorcinol) assay, ICP-MS (Inductively coupled plasma mass spectrometry) and MST (Micro-Scale Thermophoresis), we have characterised effector metal binding activity and shown preferential binding for zinc. The trace element zinc has been shown to play numerous roles in plant defence responses. This work seeks to understand the role of zinc binding in the structure and function of these effectors.