This is the report from a BSPP Lockdown Bursary.
During the COVID-19 pandemic, the BSPP provided financial support to postgraduate students whose plant pathology research had been severely disrupted by the pandemic. I was in the second year of my PhD and beginning the experiments that would provide the main body of data for my thesis, when COVID hit. Due to a health condition, I was told by my doctor to shield and stay home. Little did I know that I would not be able to return to the lab for over a year!
Whilst working from home, I wrote what I could of my thesis, authored a review on how fungal pathogens sense and acquire nutrients for Fungal Biology Reviews and conducted a study using publicly available data to reveal the threat of fungal toxins (mycotoxins) to the European food and feed supply chains. Whilst this was productive, my PhD project really depended on lab experiments I was yet to undertake. Fortunately, the BSPP’s support has enabled me to extend my PhD by three months and complete my experiments.
My project aimed to characterise how Fusarium graminearum, the fungus which causes Fusarium Head Blight (FHB) on wheat, acquires micronutrients from its host to permit development of disease. FHB is the number one floral disease of cereals and contaminates the grain with harmful mycotoxins. Currently there is no effective control for FHB, so a better understanding of the molecular determinants of this disease is needed.
My phylogenetic and transcriptomic analyses suggested that F. graminearum uses transporter proteins to acquire micronutrients from the wheat host, and that their expression is regulated by an uncharacterised transcription factor (TF). To test whether these proteins are important for disease and micronutrient acquisition, I created F. graminearum single-gene-deletion mutants lacking individual transporters or the TF. I used these strains to quantify the importance of the proteins to disease via assays for virulence, mycotoxin production and growth inside the wheat head. To determine whether the proteins are required for micronutrient acquisition, I measured the mutants’ abilities to grow in low-micronutrient environments. To confirm importer function, I complemented a micronutrient importer-deficient yeast strain with the F. graminearum transporters. Finally, I used RNA-sequencing to reveal how the TF regulates global gene expression in low micronutrient environments to promote stress tolerance and disease. Collectively, my results build the most complete picture yet of micronutrient acquisition in a fungal plant pathogen.
I would like to thank the BSPP sincerely for their financial support, which enabled to me to finish the experiments I needed for an exciting body of work that will lay the foundations for my future career in plant pathology.
University of Bath