Yeast forms dominate fungal diversity in the deep oceans.
Fungi are the principal degraders of biomass in most terrestrial ecosystems. In contrast to surface environments, deep-sea environmental gene libraries have suggested that fungi are rare and non-diverse in high-pressure marine environments. Here, we report the diversity of fungi from 11 deep-sea samples from around the world representing depths from 1,500 to 4,000 m (146-388 atm) and two shallower water column samples (250 and 500m). We sequenced 239 clones from 10 fungal-specific 18S rRNA gene libraries constructed from these samples, from which we detected only 18 fungal 18S-types in deep-sea samples. Our phylogenetic analyses show that a total of only 32 fungal 18S-types have so far been recovered from deep-sea habitats, and our results suggest that fungi, in general, are relatively rare in the deep-sea habitats we sampled. The fungal diversity detected suggests that deep-sea environments host an evolutionarily diverse array of fungi dominated by groups of distantly related yeasts, although four putative filamentous fungal 18S-types were detected. The majority of our new sequences branch close to known fungi found in surface environments. This pattern contradicts the proposal that deep-sea and hydrothermal vent habitats represent ancient ecosystems, and demonstrates a history of frequent dispersal between terrestrial and deep-sea habitats.
Bass
David
D
Department of Zoology, University of Oxford, The Tinbergen Building, South Parks Road, Oxford OX1 3PS, UK.
Howe
Alexis
A
Brown
Nick
N
Barton
Hannah
H
Demidova
Maria
M
Michelle
Harlan
H
Li
Lily
L
Sanders
Holly
H
Watkinson
Sarah C
SC
Willcock
Simon
S
Richards
Thomas A
TA
D044822:Biodiversity; D019295:Computational Biology; D017753:Ecosystem; D005658:Fungi / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D015723:Gene Library; D009792:Oceans and Seas; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D012623:Seawater / Q000382:microbiology*
D012337:RNA, Ribosomal, 18S