title: New insights into the roles of NADPH oxidases in sexual development and ascospore germination in Sordaria macrospora.
abstract: NADPH oxidase (NOX)-derived reactive oxygen species (ROS) act as signaling determinants that induce different cellular processes. To characterize NOX function during fungal development, we utilized the genetically tractable ascomycete Sordaria macrospora. Genome sequencing of a sterile mutant led us to identify the NADPH oxidase encoding nox1 as a gene required for fruiting body formation, regular hyphal growth, and hyphal fusion. These phenotypes are shared by nor1, lacking the NOX regulator NOR1. Further phenotypic analyses revealed a high correlation between increased ROS production and hyphal fusion deficiencies in nox1 and other sterile mutants. A genome-wide transcriptional profiling analysis of mycelia and isolated protoperithecia from wild type and nox1 revealed that nox1 inactivation affects the expression of genes related to cytoskeleton remodeling, hyphal fusion, metabolism, and mitochondrial respiration. Genetic analysis of nox2, lacking the NADPH oxidase 2 gene, nor1, and transcription factor deletion mutant ste12, revealed a strict melanin-dependent ascospore germination defect, indicating a common genetic pathway for these three genes. We report that gsa3, encoding a G-protein α-subunit, and sac1, encoding cAMP-generating adenylate cyclase, act in a separate pathway during the germination process. The finding that cAMP inhibits ascospore germination in a melanin-dependent manner supports a model in which cAMP inhibits NOX2 activity, thus suggesting a link between both pathways. Our results expand the current knowledge on the role of NOX enzymes in fungal development and provide a frame to define upstream and downstream components of the NOX signaling pathways in fungi.
authors.affiliation: Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr Universität Bochum, 44780 Bochum, Germany.
authors.forename: Daniela Elisabeth
authors.initials: DE
authors.lastname: Dirschnabel
authors.forename: Minou
authors.initials: M
authors.lastname: Nowrousian
authors.forename: Nallely
authors.initials: N
authors.lastname: Cano-Domínguez
authors.forename: Jesus
authors.initials: J
authors.lastname: Aguirre
authors.forename: Ines
authors.initials: I
authors.lastname: Teichert
authors.forename: Ulrich
authors.initials: U
authors.lastname: Kück
mesh_terms: D001483:Base Sequence; D003599:Cytoskeleton / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D025301:Hyphae / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D019255:NADPH Oxidases / Q000235:genetics* / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D020037:Sordariales / Q000201:enzymology / Q000254:growth & development*; D013172:Spores, Fungal / Q000235:genetics / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D017382:Reactive Oxygen Species; D019255:NADPH Oxidases
keywords: NOX enzymes; RNA-seq; STE12; ascospore germination; fruiting body formation