High Fungal Diversity and Abundance Recovered in the Deep-Sea Sediments of the Pacific Ocean

Abstract

Knowledge about the presence and ecological significance of bacteria and archaea in the deep-sea environments has been well recognized, but the eukaryotic microorganisms, such as fungi, have rarely been reported. The present study investigated the composition and abundance of fungal community in the deep-sea sediments of the Pacific Ocean. In this study, a total of 1,947 internal transcribed spacer (ITS) regions of fungal rRNA gene clones were recovered from five sediment samples at the Pacific Ocean (water depths ranging from 5,017 to 6,986 m) using three different PCR primer sets. There were 16, 17, and 15 different operational taxonomic units (OTUs) identified from fungal-universal, Ascomycota-, and Basidiomycota-specific clone libraries, respectively. Majority of the recovered sequences belonged to diverse phylotypes of Ascomycota (25 phylotypes) and Basidiomycota (18 phylotypes). The multiple primer approach totally recovered 27 phylotypes which showed low similarities (≤97 %) with available fungal sequences in the GenBank, suggesting possible new fungal taxa occurring in the deep-sea environments or belonging to taxa not represented in the GenBank. Our results also recovered high fungal LSU rRNA gene copy numbers (3.52 × 10(6) to 5.23 × 10(7)copies/g wet sediment) from the Pacific Ocean sediment samples, suggesting that the fungi might be involved in important ecological functions in the deep-sea environments.

Species Richness and Adaptation of Marine Fungi from Deep-Subseafloor Sediments

“…Among the Basidiomycota, Agaricomycetes were the most frequently recovered, with isolates being affiliated with Bjerkandera spp., Sistotrema brinkmannii, Trametes versicolor, and uncultured Agaricomycetes. Although the cultivable representatives of Agaricomycetes appear to be rare in marine environments (36), the molecular signatures of Agaricomycetes have been detected in deep-sea environments (3,9,11,45) and Agaricomycetes have been identified to be the dominant fungal class in mangrove habitats (46).…”

Multi-year assessment of coastal planktonic fungi reveals environmental drivers of diversity and abundance

“…Xu et al (2014) used a similar Q-PCR-based approach to quantify fungi in sediment samples collected from five deep-sea sites in the Pacific Ocean and showed that Fungi-specific 28S rRNA gene copies ranged from 3.5 × 10 6 to 5.2 × 10 7 copies per g wet sediment (Xu et al, 2014). Assuming that 1 g sediment≈1 ml seawater, then as with bacteria in sediments and bacterioplankton, fungi in sediments occur at higher abundances than mycoplankton in the water column.…”

“…Several studies have shown that fungi are abundant in marine sediments (Orsi et al, 2013a, b;Xu et al, 2014;Taylor and Cunliffe, 2015). Xu et al (2014) used a similar Q-PCR-based approach to quantify fungi in sediment samples collected from five deep-sea sites in the Pacific Ocean and showed that Fungi-specific 28S rRNA gene copies ranged from 3.5 × 10 6 to 5.2 × 10 7 copies per g wet sediment (Xu et al, 2014).…”

Biotechnological Potential of Cold Adapted Pseudoalteromonas spp. Isolated from ‘Deep Sea’ Sponges

“…We have previously reported on the microbial biodiversity of deep sea sponges sampled at depths of between 760 and 2900 m below sea level, indicating that the microbial community structures of these sponges may represent an untapped source of potential microbial biodiversity [25,26]. Bacterial and fungal communities from deep sea sediments also continue to receive attention, not only from an ecological standpoint [27], but also due to the ability of microorganisms isolated from this ecosystem to produce novel bioactive molecules [28,29] and enzymes of biotechnological importance [30,31]. Cold-active enzymes are of particular interest as they possess a range of structural features that promote flexibility at the active site, low substrate affinity, and high specific activity at low temperatures.…”