Changes in macromolecular content and AOX activity of Ustilago maydis: from exponential to stationary phase

The life cycle of Ustilago maydis involves three distinct morphological stages: sporidia, dikaryotic hyphae, and teliospores. While the yeast-like sporidia form is well described, the metabolic strategies enabling survival throughout its growth cycle remain unexplored. Here, we characterize the growth dynamics and the metabolic response of U. maydis in a YPD medium containing low (0.5%) or high (1.2%) glucose. Results indicate that the duration of exponential growth for U. maydis cells was the same in both media, with a specific growth rate of approximately 0.26 h^- 1. For U. maydis cells cultivated in YPD-0.5% medium, the transition to the stationary growth phase occurred between 72 and 96 h, coinciding with a decrease in cellular biomass, a reduction in total RNA concentration, and diminished alternative oxidase (AOX) activity. Furthermore, U. maydis exhibited a short lifespan in the stationary phase, with most cells losing replicative capacity within 24-36 h.