Deep-Sea Fungi

Abstract

This chapter focuses on issues related to collection and isolation of deep-sea fungi, direct detection in deep-sea sediments, diversity and biomass, growth and physiology, adaptations, and their biotechnological applications. The presence of fungi in oceanic waters and the deep sea has been sporadically reported in the past. Their presence in shells collected from deep-sea waters at a depth of 4,610 m was the first report on deep-sea fungi. Immunofluorescence has been widely used to detect specific fungi in terrestrial and in a few marine substrates. The authors used this for detecting one of the commonly isolated fungi, Aspergillus terreus (isolate A 4634), from deep-sea sediments of the Central Indian Basin. The deep-sea fungi when grown under elevated pressure synthesized extracellular protease, albeit in very low quantities in comparison with that produced under 0.1 MPa. Aspergillus ustus (NIOCC20) isolated by the authors from deep-sea sediments produced cold-active alkaline serine protease, whereas A. ustus obtained from a terrestrial habitat did not. This might be due to differences in strains but may also indicate the adaptation that deep-sea fungi have undergone for their survival. Study of the cold shock or stress proteins or genes produced in response to hydrostatic pressure shock in fungi using proteomics and microarray technology will help to understand the response in eukaryotic organisms to pressure. New techniques for retrieval of sediment samples with in situ pressure, isolation, and culture of the vast diversity of organisms from the deep sea will open new vistas in deep-sea biology.