A Highly Efficient Method for Measuring Oxygen Consumption Rate in Fusarium graminearum

The filamentous ascomycete Fusarium graminearum is the causal agent of Fusarium head blight, a devastating disease of cereals with a worldwide distribution. Fusarium graminearum infections result in a quantitative yield reduction by impairing the growth of the kernels, and a qualitative reduction by poisoning the remaining kernels with mycotoxins toxic to animals and humans. The colonization of wheat florets by phytopathogenic fungus requires high-efficiency energy generation in the mitochondria (Bönnighausen et al., 2015). Mitochondrial activity in microorganisms can be measured using the oxygen consumption rate (OCR) method. Here we describe a method for the assessment of fungal respiration using an XF24 extracellular flux analyzer. The Seahorse XF Analyzer is a microplate-based respirometer which measures oxygen consumption by changes in the fluorescence of immobilized fluorophores (Gerencser et al., 2009). Multiple mitochondrial parameters can be measured by the application of mitochondrial substrates and inhibitors which are injected automatically during the assays via ports (Divakaruni et al., 2014). The experimental work-flow involves the inoculation with conidia and the application of specific inhibitors of mitochondrial functions. The analysis of fungal respiration represents a valuable tool that complements classical phenotypic screenings.