A mutant defective in sexual development produces aseptate ascogonia.
The transition from the vegetative to the sexual cycle in filamentous ascomycetes is initiated with the formation of ascogonia. Here, we describe a novel type of sterile mutant from Sordaria macrospora with a defect in ascogonial septum formation. This mutant, named pro22, produces only small, defective protoperithecia and carries a point mutation in a gene encoding a protein that is highly conserved throughout eukaryotes. Sequence analyses revealed three putative transmembrane domains and a C-terminal domain of unknown function. Live-cell imaging showed that PRO22 is predominantly localized in the dynamic tubular and vesicular vacuolar network of the peripheral colony region close to growing hyphal tips and in ascogonia; it is absent from the large spherical vacuoles in the vegetative hyphae of the subperipheral region of the colony. This points to a specific role of PRO22 in the tubular and vesicular vacuolar network, and the loss of intercalary septation in ascogonia suggests that PRO22 functions during the initiation of sexual development.
Bloemendal
Sandra
S
Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, ND7/131, Universitätsstrasse 150, 44780 Bochum, Germany.
Lord
Kathryn M
KM
Rech
Christine
C
Hoff
Birgit
B
Engh
Ines
I
Read
Nick D
ND
Kück
Ulrich
U
D000595:Amino Acid Sequence; D048690:Fruiting Bodies, Fungal / Q000737:chemistry / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D015966:Gene Expression Regulation, Fungal; D025301:Hyphae / Q000737:chemistry / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D016415:Sequence Alignment; D020037:Sordariales / Q000737:chemistry / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism
D005656:Fungal Proteins