Characterising some mechanisms of iron homeostasis in selected Armillaria species

Abstract

Plant-pathogenic organisms including fungi pose significant risks to agriculture, horticulture, and natural and plantation forests. This affects attainment of some of the 17 Sustainable Development Goals (SDGs) to transform our world. The affected goals include Goal 2 – “End hunger, achieve food security and improved nutrition and promote sustainable agriculture” and Goal 15 – “Protect, restore, and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss”. Species of Armillaria belong to the Physalacriaceae and have a worldwide distribution with a range of plant-pathogenic lifestyles. Current control strategies are inefficient. Hence, there is an urgent need to develop more efficient and sustainable control strategies against the plant-pathogenic members of this group. To achieve this, a deeper understanding is needed about the cellular and molecular defence strategies employed by these fungi. Therefore, the overall objective of this thesis was to increase our understanding of mechanisms employed by Armillaria in comparison to other species in the Physalacriaceae with regards to iron homeostasis. This was done by studying some secondary metabolite gene clusters, and investigating growth, siderophore production, and proteomic and secretomic response of Armillaria species to iron. A multidisciplinary approach including genetics, comparative genomics, in vitro bioassays, and proteomics was employed. The findings of this thesis represent the first study of some mechanisms underpinning iron homeostasis by Armillaria species in comparison to some other members of the Physalacriaceae.