DEWA ENCODES A FUNGAL HYDROPHOBIN COMPONENT OF THE ASPERGILLUS SPORE WALL

An anonymous cDNA clone, pCAN4, was shown previously to correspond to an mRNA that accumulates preferentially during asexual sporulation of the filamentous fungus Aspergillus nidulans. The peptide encoded by pC AN4 is a fungal hydrophobin, a group of small, hydrophobic cell wall p roteins. When the CAN4 gene was disrupted, conidia and conidiophores a ppeared to be normal, but sporulating colonies wetted more rapidly wit h detergent solutions than did the wild type. We renamed CAN4 dewA for the detergent (w) under bar ettable phenotype and mapped it to chromo some V, 24 map units from cysC. The A. nidulans rodA gene also encodes a sporulation-specific fungal hydrophobin. Spores of a dewA(-) rodA(- ) double mutant were less hydrophobic than those of either mutant alon e, showing that dewA and rodA contribute independently to spore-wall h ydrophobicity. Immunolocalization of DewA by epitope tagging demonstra ted that DewA is present in the spore wall, but not in the walls of ge rm tubes, hyphae or cells of the spore-producing conidiophore. We conc lude that dewA encodes a new fungal hydrophobin component of the conid ial wall.