English
Fungal developmental programs drive transmission, niche adaptation, and stress tolerance. In pathogenic fungi, sexual reproduction fuels genetic diversification that can reshuffle virulence traits, enable antifungal resistance, and yield environmentally persistent infectious spores. To translate these principles into actionable insight, we focus on Cryptococcus neoformans, a major human pathogen in which spores arising from unisexual and bisexual reproduction initiate infection.
An integrated, genome-scale view of core signaling components including transcription factors and kinases are therefore required to resolve the networks governing development. Building on our systematic functional profiling of 155 transcription factors and 129 kinases, we identified 37 transcription factors and 41 kinases implicated in C. neoformans sexual development with unisexual mating. These include components of established mating pathways (Cpk1 and Hog1 MAPK cascades; cAMP/PKA pathway), yet many candidates remain mechanistically unassigned. To this end, we generated knockout mutants of mating-regulating transcription factors and kinases in the YL99 strain, the MATa isogenic counterpart of the MATα H99 strain. These mutants were used to investigate sexual development in C. neoformans through bilateral mating by analyzing each developmental stage in detail. The stages examined included pheromone production, cell fusion, filamentous growth, clamp connection, and the formation of basidia and basidiospores. Through these analyses, we have identified uncharacterized transcription factors and kinases that act as potential activators or inhibitors at different stages of mating. Ultimately, this study will focus on mapping and discovering the functions of the mating-regulating transcription factors and kinases, and elucidating complex signaling networks in the developmental process of C. neoformans.
