Six hydrophobins are involved in hydrophobin rodlet formation in Aspergillus nidulans and contribute to hydrophobicity of the spore surface

• Published in: PloS one Vol. 9; no. 4; p. e94546
• Main Authors: Grünbacher, André, Throm, Tanja, Seidel, Constanze, Gutt, Beatrice, Röhrig, Julian, Strunk, Timo, Vincze, Paul, Walheim, Stefan, Schimmel, Thomas, Wenzel, Wolfgang, Fischer, Reinhard
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 01.04.2014; Public Library of Science (PLoS)
• Subjects: Amino Acid Sequence; Analysis; Applied physics; Aspergillus; Aspergillus nidulans; Aspergillus nidulans - genetics; Aspergillus nidulans - metabolism; Atomic force microscopy; Atomic structure; Biology and Life Sciences; Cladosporium fulvum; Conidia; Distribution; Fungal Proteins - genetics; Fungal Proteins - metabolism; Fungi; Gene Expression Regulation, Fungal; Genes; Genetic Complementation Test; Genomes; Hydrophobic and Hydrophilic Interactions; Hydrophobicity; Hydrophobins; Laboratories; Microscopy; Microscopy, Atomic Force; Molecular Sequence Data; Physical Sciences; Physiological aspects; Protein Isoforms - genetics; Protein Isoforms - metabolism; Proteins; Research and Analysis Methods; Secretion; Sequence Alignment; Spores, Fungal - chemistry; Spores, Fungal - genetics; Spores, Fungal - metabolism; Surface Properties; Germany
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0094546

Hydrophobins are amphiphilic proteins able to self-assemble at water-air interphases and are only found in filamentous fungi. In Aspergillus nidulans two hydrophobins, RodA and DewA, have been characterized, which both localize on the conidiospore surface and contribute to its hydrophobicity. RodA is the constituent protein of very regularly arranged rodlets, 10 nm in diameter. Here we analyzed four more hydrophobins, DewB-E, in A. nidulans and found that all six hydrophobins contribute to the hydrophobic surface of the conidiospores but only deletion of rodA caused loss of the rodlet structure. Analysis of the rodlets in the dewB-E deletion strains with atomic force microscopy revealed that the rodlets appeared less robust. Expression of DewA and DewB driven from the rodA promoter and secreted with the RodA secretion signal in a strain lacking RodA, restored partly the hydrophobicity. DewA and B were able to form rodlets to some extent but never reached the rodlet structure of RodA. The rodlet-lacking rodA-deletion strain opens the possibility to systematically study rodlet formation of other natural or synthetic hydrophobins.