Open AccessTranscription Factor SomA Is Required for Adhesion, Development and Virulence of the Human Pathogen Aspergillus fumigatus
Author(s) -
Chih-Wei Lin,
Christoph Sasse,
Jennifer Gerke,
Oliver Valerius,
Henriette Irmer,
Holm Frauendorf,
Thorsten Heinekamp,
Maria Straßburger,
VanTuan Tran,
Britta Herzog,
Susanna Braus-Stromeyer,
Gerhard H. Braus
Publication year - 2015
Publication title -
plos pathogens
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.719
H-Index - 206
eISSN - 1553-7374
pISSN - 1553-7366
DOI - 10.1371/journal.ppat.1005205
Subject(s) - biology , conidiation , transcription factor , aspergillus fumigatus , microbiology and biotechnology , aspergillus nidulans , soma , saccharomyces cerevisiae , phenotype , promoter , yeast , virulence , gene , gene expression , mutant , genetics , neuroscience
The transcription factor Flo8/Som1 controls filamentous growth in Saccharomyces cerevisiae and virulence in the plant pathogen Magnaporthe oryzae . Flo8/Som1 includes a characteristic N-terminal LUG/LUH-Flo8-single-stranded DNA binding (LUFS) domain and is activated by the cAMP dependent protein kinase A signaling pathway. Heterologous SomA from Aspergillus fumigatus rescued in yeast flo8 mutant strains several phenotypes including adhesion or flocculation in haploids and pseudohyphal growth in diploids, respectively. A . fumigatus SomA acts similarly to yeast Flo8 on the promoter of FLO11 fused with reporter gene ( LacZ ) in S . cerevisiae . FLO11 expression in yeast requires an activator complex including Flo8 and Mfg1. Furthermore, SomA physically interacts with PtaB, which is related to yeast Mfg1. Loss of the somA gene in A . fumigatus resulted in a slow growth phenotype and a block in asexual development. Only aerial hyphae without further differentiation could be formed. The deletion phenotype was verified by a conditional expression of somA using the inducible Tet-on system. A adherence assay with the conditional somA expression strain indicated that SomA is required for biofilm formation. A ptaB deletion strain showed a similar phenotype supporting that the SomA/PtaB complex controls A . fumigatus biofilm formation. Transcriptional analysis showed that SomA regulates expression of genes for several transcription factors which control conidiation or adhesion of A . fumigatus . Infection assays with fertilized chicken eggs as well as with mice revealed that SomA is required for pathogenicity. These data corroborate a complex control function of SomA acting as a central factor of the transcriptional network, which connects adhesion, spore formation and virulence in the opportunistic human pathogen A . fumigatus .