Hydrophobin genes and their expression in conidial and aconidial Neurospora species

Homologs of the gene encoding the hydrophobin EAS from Neurospora crassa have been identified both in the other conidial species of Neurospora (N. discreta, N. intermedia, N. sitophila, and N. tetrasperma) and selected aconidial species (N. africana, N. dodgei, N. lineolata, N. pannonica, and N. terricola). Southern blot analysis indicated the presence of a single gene in all species examined. EAS-like proteins were purified from the conidial species and each was shown to be the proteolytically processed gene-product of the corresponding eas homolog. While EAS-like proteins were not detected in the aconidial species, putative eas transcripts were detected in some isolates following RT-PCR and the aerial hyphae of these species were hydrophobic. DNA sequences of the coding region of the eas homologs were amplified by PCR and cloned and sequenced from all species except N. pannonica. Phylogenetic analysis of these sequences produced two clusters, the first comprising the conidiating species N. crassa, N. intermedia, N. sitophila, and N. tetrasperma forming a closely related group with N. discreta more distant, and the second comprising the aconidial species N. africana, N. dodgei, N. lineolata forming another closely related group with N. terricola more distant.