Transcriptomic resource and hormonal profiling of the smut fungus, <i>Ustilago esculenta</i>, coexisting with <i>Zizania latifolia</i> and forming Makomotake

Ustilago esculenta is a smut fungus that parasitizes Zizania latifolia, forming edible fungal galls known as Makomotake. In this study, we quantified indole-3-acetic acid (IAA) produced in liquid-cultured U. esculenta and in fungal galls at different growth stages. IAA was detected in both samples, and its content showed a tendency to increase during the mature growth stage in October. Furthermore, RNA-seq analysis was performed to investigate gene expression changes in U. esculenta during different developmental stages. The gene involved in spore maturation was upregulated in October, consistent with fungal maturation. Moreover, numerous genes with unknown functions were significantly upregulated, highlighting potential targets for further investigation. These findings provide insights into the molecular mechanisms underlying fungal gall development and the symbiotic relationship between U. esculenta and Z. latifolia, providing a foundation for future research on fungal-plant interactions.