Structure/function studies of effectors from the potato late blight and rice blast pathogens

Varden, Freya (2019) Structure/function studies of effectors from the potato late blight and rice blast pathogens. Doctoral thesis, University of East Anglia.

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In a world with an increasing population and changing climate, the availability of food is a growing concern. Crop plants struggle in the face of increasing stresses, including the pressure of diseases that are spread by microbial pathogens. Understanding how plants defend themselves against disease is vital for finding solutions to food shortages.
Microbial pathogens deploy effector proteins as tools to promote infection, and plants evolve to recognise effectors and launch an immune response accordingly. This PhD project focuses on structure/function studies of two effectors from pathogens of important crop plants: the Magnaporthe oryzae (rice blast) effector AVR-Pia, and the Phytophthora infestans (potato late blight) effector PexRD24.
This work shows that a rice immune receptor pair, Pikp-1/Pikp-2, is able to recognise AVR-Pia, even though this effector is genetically characterised as being recognised by a different receptor. The structural basis of Pikp-1 interacting with AVR-Pia through an integrated domain is shown, and attempts are made to engineer this integrated domain to recognise AVR-Pia more strongly in planta, with some success.
For PexRD24, the interaction with a potato host target enzyme, protein phosphatase 1, is explored. While many issues were encountered with the production of stable, soluble protein, it is shown that PexRD24 can interact with the enzyme in vitro. The enzyme still retains function in complex with the effector, indicating that the role of the effector is not to inhibit phosphatase activity, and may enhance it.
This research uses both biochemical and structural techniques, alongside in planta assays, to broaden the field of knowledge in molecular plant-microbe interactions. By gaining a detailed understanding of how such interactions take place, it will be possible to start engineering plants with a more robust immune system. Through protecting crops against devastating losses by microbial diseases, we move a step closer to global food security.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: Nicola Veasy
Date Deposited: 14 Mar 2019 16:09
Last Modified: 30 Sep 2020 00:38


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