The Aspergillus nidulans cetA and calA genes are involved in conidial germination and cell wall morphogenesis.
The Aspergillus nidulans genes cetA (AN3079.2) and calA (AN7619.2) encode a novel class of fungal thaumatin-like proteins of unknown function. Deletion of cetA does not result in an observable phenotype [Greenstein, S., Shadkchan, Y., Jadoun, J., Sharon, C., Markovich, S., Osherov, N., 2006. Analysis of the Aspergillus nidulans thaumatin-like cetA gene and evidence for transcriptional repression of pyr4 expression in the cetA-disrupted strain. Fungal Genet. Biol. 43, 42-53]. We prepared knockout calA and calA/cetA A. nidulans strains. The calA mutants were phenotypically identical to the wild-type. In contrast, the cetA/calA double mutant showed a synthetic lethal phenotype suggesting that the two genes affect a single function or pathway: most of its conidia were completely inhibited in germination. Many collapsed and underwent lysis. A few showed abnormal germination characterized by short swollen hyphae and abnormal hyphal branching. Nongerminated conidia contained a single condensed nucleus suggesting a block in early germination. This is the first functional analysis of the novel cetA/calA family of thaumatin-like genes and their role in A. nidulans conidial germination. We show that CETA and CALA are secreted proteins that together play an essential role in early conidial germination.
Belaish
Ravit
R
Department of Human Microbiology, Sackler School of Medicine, Tel-Aviv University, Ramat-Aviv 69978, Tel-Aviv, Israel.
Sharon
Haim
H
Levdansky
Emma
E
Greenstein
Shulamit
S
Shadkchan
Yana
Y
Osherov
Nir
N
D001233:Aspergillus nidulans / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D015152:Blotting, Northern; D015153:Blotting, Western; D002473:Cell Wall / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D008957:Models, Genetic; D009024:Morphogenesis; D009154:Mutation; D010641:Phenotype; D013172:Spores, Fungal / Q000235:genetics* / Q000254:growth & development
D005656:Fungal Proteins