Insight into picophytoplankton diversity of the subarctic White Sea-The first recording of Pedinophyceae in environmental DNA

Abstract

Operational taxonomic units 94%-95% similar to the known Pedinophyceae were found as a result of high-through sequencing of 18S rDNA V4 amplicons of environmental DNA from the summer picophytoplankton samples from the White Sea. Partial sequence of a ribosomal operon (the 5,298 bp includes partial 18S and 28S rDNA, complete 5.8S rDNA, ITS1, and ITS2 sequences) and a partial 2,112 bp chloroplast 23S rDNA sequence White Sea Pedinophyceae was amplified from metagenomic DNA by specific primers and sequenced. A new phylotype was designated as uncultured Pedinophyceae WS. On Chlorophyta phylogenetic trees the discovered phylotype occupies a basal position in the Marsupiomonadales clade. The synapomorphic base substitutions in rRNA hairpins confirm the relationship of Pedinophyceae WS to Marsupiomonadales and its difference from known genera of the order. The obtained results extend knowledge of picophytoplankton diversity in subarctic waters.

Keywords: Marsupiomonadales; Pedinophyceae; White Sea; environmental DNA; picophytoplankton; rDNA sequence; rRNA secondary structure.