title: New insights from an old mutant: SPADIX4 governs fruiting body development but not hyphal fusion in Sordaria macrospora.
abstract: During the sexual life cycle of filamentous fungi, multicellular fruiting bodies are generated for the dispersal of spores. The filamentous ascomycete Sordaria macrospora has a long history as a model system for studying fruiting body formation, and two collections of sterile mutants have been generated. However, for most of these mutants, the underlying genetic defect remains unknown. Here, we investigated the mutant spadix (spd) that was generated by X-ray mutagenesis in the 1950s and terminates sexual development after the formation of pre-fruiting bodies (protoperithecia). We sequenced the spd genome and found a 22 kb deletion affecting four genes, which we termed spd1-4. Generation of deletion strains revealed that only spd4 is required for fruiting body formation. Although sterility in S. macrospora is often coupled with a vegetative hyphal fusion defect, Δspd4 was still capable of fusion. This feature distinguishes SPD4 from many other regulators of sexual development. Remarkably, GFP-tagged SPD4 accumulated in the nuclei of vegetative hyphae and fruiting body initials, the ascogonial coils, but not in sterile tissue from the developing protoperithecium. Our results point to SPD4 as a specific determinant of fruiting body formation. Research on SPD4 will, therefore, contribute to understanding cellular reprogramming during initiation of sexual development in fungi.
authors: Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, ND6/166, Universitätsstrasse 150, 44780, Bochum, Germany. ines.teichert@rub.de.
authors: Ines
authors: http://orcid.org/0000-0002-2993-6756
authors: I
authors: Teichert
authors: Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, ND6/166, Universitätsstrasse 150, 44780, Bochum, Germany.|Abteilung Molekulare Genetik I, Universität Duisburg-Essen, 45141, Essen, Germany.
authors: Miriam
authors: M
authors: Lutomski
authors: Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, ND6/166, Universitätsstrasse 150, 44780, Bochum, Germany.
authors: Ramona
authors: R
authors: Märker
authors: Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, ND6/166, Universitätsstrasse 150, 44780, Bochum, Germany.
authors: Minou
authors: M
authors: Nowrousian
authors: Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, ND6/166, Universitätsstrasse 150, 44780, Bochum, Germany.
authors: Ulrich
authors: U
authors: Kück
mesh_terms: D002467:Cell Nucleus / Q000378:metabolism; D048690:Fruiting Bodies, Fungal; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D025301:Hyphae / Q000378:metabolism; D016296:Mutagenesis; D020037:Sordariales / Q000166:cytology* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism
chemical_list: D005656:Fungal Proteins
keywords: Fungal sexual development; Sordaria macrospora; Vegetative hyphal fusion; Whole-genome sequencing