title: Phylogenetic analyses and nitrate-reducing activity of fungal cultures isolated from the permanent, oceanic oxygen minimum zone of the Arabian Sea.
abstract: Reports on the active role of fungi as denitrifiers in terrestrial ecosystems have stimulated an interest in the study of the role of fungi in oxygen-deficient marine systems. In this study, the culturable diversity of fungi was investigated from 4 stations within the permanent, oceanic, oxygen minimum zone of the Arabian Sea. The isolated cultures grouped within the 2 major fungal phyla Ascomycota and Basidiomycota; diversity estimates in the stations sampled indicated that the diversity of the oxygen-depleted environments is less than that of mangrove regions and deep-sea habitats. Phylogenetic analyses of 18S rRNA sequences revealed a few divergent isolates that clustered with environmental sequences previously obtained by others. This is significant, as these isolates represent phylotypes that so far were known only from metagenomic studies and are of phylogenetic importance. Nitrate reduction activity, the first step in the denitrification process, was recorded for isolates under simulated anoxic, deep-sea conditions showing ecological significance of fungi in the oxygen-depleted habitats. This report increases our understanding of fungal diversity in unique, poorly studied habitats and underlines the importance of fungi in the oxygen-depleted environments.
authors: Biological Oceanography Division, CSIR - National Institute of Oceanography, Dona Paula, Goa 403 004, India.
authors: Cathrine Sumathi
authors: CS
authors: Manohar
authors: Larissa Danielle
authors: LD
authors: Menezes
authors: Kesava Priyan
authors: KP
authors: Ramasamy
authors: Ram M
authors: RM
authors: Meena
mesh_terms: D017753:Ecosystem; D005658:Fungi / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D008969:Molecular Sequence Data; D009566:Nitrates / Q000378:metabolism*; D009792:Oceans and Seas; D010084:Oxidation-Reduction; D010100:Oxygen / Q000032:analysis / Q000378:metabolism; D010802:Phylogeny; D012623:Seawater / Q000032:analysis / Q000382:microbiology*
chemical_list: D009566:Nitrates; D010100:Oxygen
keywords: Arabian Sea; activité de réduction des nitrates; champignons cultivables; culturable fungi; diversité moléculaire; mer d’Arabie; molecular diversity; nitrate-reducing activity; oxygen minimum zone; zone de minimum