Pleiotropic functions of SscA on the asexual spore of the human pathogenic fungus Aspergillus fumigatus

ABSTRACT

Asexual spores, called conidia, are key reproductive fungal particles that enable survival in harsh environmental conditions or host systems. The conidia can infect humans, animals, and plants to cause various fungal diseases. Transcription factors, including VosA, WetA, and SscA, have key roles in conidia formation and long-term survival in Aspergillus nidulans. Herein, we report the pleiotropic functions of SscA in the conidia of the human pathogen A. fumigatus. The deletion of sscA increased conidia formation despite decreased fungal growth. Absence of sscA impaired long-term survival and reduced spore resistance to various stresses, including heat, UV, and oxidation. Transcriptomic analyses showed that SscA involved the mRNA expression of cell wall organisation-related genes. Importantly, the sscA deletion mutant conidia contained an increased amount of β-glucan and chitin compared to wild type conidia. In addition, conidial gliotoxin production was decreased in the sscA deletion strain. Overall, SscA has pleiotropic roles in conidia formation, maturation and dormancy and mycotoxin production in A. fumigatus.

KEYWORDS:

• Aspergillus fumigatus
• asexual spore
• spore-specific transcription factor
• C₂H₂ zinc finger domain
• SscA
• spore maturation
• spore dormancy

Acknowledgments

The work by SYE was supported by the National Research Foundation of Korea (NRF) grant to SYE funded by the Korean government (MSIP: 2021R1A6A3A13044577). The work by HSP was supported by the National Research Foundation of Korea (NRF) grant to HSP funded by the Korean government (MSIP: 2020R1C1C1004473). This research was supported by Biological Materials Specialized Graduate Program through the Korea Environmental Industry & Technology Institute (KEITI) funded by the Ministry of Environment (MOE) and supported by the Korea Basic Science Institute (National Research Facilities and Equipment Center) grant funded by the Ministry of Education (2021R1A6C101A416).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

All RNA-seq data files are available at the NCBI Sequence Read Archive (SRA) database under the accession number PRJNA983063 for WT and ΔsscA of Aspergillus fumigatus conidia RNA-seq.

Supplementary Material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/21501203.2023.2294061

Additional information

Funding

The work was supported by the Korea Basic Science Institute (2021R1A6C101A416); Ministry of Environment (Korea Environmental Industry Technology Institute); National Research Foundation of Korea (2020R1C1C1004473); National Research Foundation of Korea (2021R1A6A3A13044577).