Annotation of stress–response proteins in the aspergilli

Stress–response proteins of Aspergillus nidulans, Aspergillus clavatus, Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Aspergillus oryzae, Aspergillus terreus and Neosartorya fischeri (3908 in total) were annotated and grouped according to stress types (http://193.6.155.82/AspergillusStress/). All genomes harboured elements of the SskA–HogA/SakA stress signalling pathway. There are accumulating data pointing at the importance of SskA–HogA/SakA signalling in different types of stress–responses in the aspergilli and, in this regard, these filamentous fungi are closer to fission yeast than to budding yeast. The abundance of annotated stress sensing histidine kinases and transcriptional regulators in each Aspergillus species indicates that the applicability of yeast-based models to fully describe and explain the stress–responses of these fungi is limited. Most excitingly, putative orthologues of both Saccharomyces cerevisiae Msn2p/Msn4p C2H2 zinc finger-type and Schizosaccharomyces pombe Atf1 bZip-type ‘general stress’ transcription factors were annotated in the aspergilli, foreshadowing complex and robust stress defence systems in these euascomycetes.