This research examined how genes are activated during spore formation in an important symbiotic fungus that helps trees grow. The study revealed complex genetic programs that control spore development and energy storage in the fungus. This knowledge advances our understanding of fungal reproduction and could help improve forest management. Impacts on everyday life: – Better understanding of beneficial fungi could improve tree growth in forestry – Knowledge of fungal spore formation may help develop better fungal inoculants for plants – Insights into lipid metabolism could be relevant for biofuel production – Understanding symbiotic relationships between fungi and trees helps protect forest ecosystems – Could lead to improved methods for growing valuable edible mushrooms