The Aspergillus nidulans cetA and calA genes are involved in conidial germination and cell wall morphogenesis

Ravit Belaish, Haim Sharon, Emma Levdansky, Shulamit Greenstein, Yana Shadkchan, Nir Osherov*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish
Pages (from-to)232-242
Number of pages11
JournalFungal Genetics and Biology
Issue number3
StatePublished - Mar 2008


  • Aspergillus nidulans
  • Cell wall integrity
  • Cell wall morphogenesis
  • Conidial germination
  • Thaumatin-like protein


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