Cultivation and diversity of fungi buried in the Baltic Sea sediments

Abstract:

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Studies on molecular biological and cultivation have been done for the prokaryotic microbial community in the deep biosphere. Compare to the prokaryotic community, few attempts have been done for eukaryotic microbial community. Here we report the study on fungi buried in deep-subsurface sediments by approaches of both cultivation and molecular diversity survey. Cultivation targeting fungi has been done using a sequential sediment samples obtained from the Baltic Sea, Landsort Deep site during the IODP expedition 347. 6 culture media with different nutrition and salt concentration have been tried for the fungi cultivation. 50 isolates of fungi were obtained from the sediment samples. The surface sediments showed richness of fungi strains but not for the deep sediments. Internal Transcribed Spacer (ITS) regions of RNA genes were amplified and for the identification of the isolates. The isolates were classified to 11 different genera. Pseudeurotium bakeri was the dominant strain throughout the glacial and interglacial sediments. We also found different representative fungal strains from glacial and interglacial sediments, suggesting the cultivated strains are buried from different sources. The survey of fungal diversity was done by sequencing the 18S RNA genes in the total DNA extracted from selected sediment samples. Fungi community showed different cluster in the glacial and interglacial sediments.Our results revealed the presence and activity of fungi in the deep biosphere of the Baltic sea and provided evidence of fungal community response to the climate change.