MADS-Box Transcription Factor MadsA Regulates Dimorphic Transition, Conidiation, and Germination of Talaromyces marneffei

The opportunistic human pathogen exhibits a temperature-dependent dimorphic transition, which is closely related with its pathogenicity. This species grows as multinucleate mycelia that produce infectious conidia at 25°C, while undergoes a dimorphic transition to generate uninucleate yeast form cells at 37°C. The mechanisms of phenotype switching are not fully understood. The transcription factor gene is a member of the MADS-box gene family. Previously, it was found that overexpression of gene resulted in mycelial growth instead of yeast form at 37°C. In the current study, the deletion mutant (Δ ) and complemented strain (CMA) were constructed by genetic manipulation. We compared the phenotypes, growth, conidiation, conidial germination and susceptibility to stresses (including osmotic and oxidative) of the Δ with the wild-type (WT) and CMA strains. The results showed that the Δ displayed a faster process of the yeast-to-mycelium transition than the WT and CMA. In addition, the deletion of led to a delay in conidia production and conidial germination. The tolerance of Δ conidia to hydrogen peroxide was better than that of the WT and CMA strains. Then, RNA-seq was performed to identify differences in gene expression between the Δ mutant and WT strain during the yeast phase, mycelium phase, yeast-to-mycelium transition and mycelium-to-yeast transition, respectively. Gene ontology functional enrichment analyses indicated that some important processes such as transmembrane transport, oxidation-reduction process, protein catabolic process and response to oxidative stress were affected by the deletion. Together, our results suggest that functions as a global regulator involved in the conidiation and germination, especially in the dimorphic transition of . Its roles in the survival, pathogenicity and transmission of require further investigation.