M.S Reza, A. Kobiyama, Y. Yamada, Y. Ikeda, D. Ikeda, N. Mizusawa, K. Ikeo, S. Sato, T. Ogata, M. Jimbo, T. Kudo, S. Kaga, S. Watanabe, K. Naiki, Y. Kaga, K. Mineta, V. Bajic, T. Gojobori, S. Watabe
Gene, 665, pp. 192-200, (2018)
16S rRNA, Bacterial diversity, Metagenomics, Ofunato Bay, Whole genome sequencing
The Ofunato Bay in Iwate Prefecture, Japan is a deep coastal bay located
at the center of the Sanriku Rias Coast and considered an economically
and environmentally important asset. Here, we describe the first whole
genome sequencing (WGS) study on the microbial community of the bay,
where surface water samples were collected from three stations along its
length to cover the entire bay; we preliminarily sequenced a 0.2 μm
filter fraction among sequentially size-fractionated samples of 20.0,
5.0, 0.8 and 0.2 μm filters, targeting the free-living fraction only.
From the 0.27-0.34 Gb WGS library, 0.9 × 106-1.2 × 106
reads from three sampling stations revealed 29 bacterial phyla (~80% of
assigned reads), 3 archaeal phyla (~4%) and 59 eukaryotic phyla (~15%).
Microbial diversity obtained from the WGS approach was compared with
16S rRNA gene results by mining WGS metagenomes, and we found similar
estimates. The most frequently recovered bacterial sequences were
Proteobacteria, predominantly comprised of 18.0-19.6% Planktomarina
(Family Rhodobacteraceae) and 13.7-17.5% Candidatus Pelagibacter (Family
Pelagibacterales). Other dominant bacterial genera, including
Polaribacter (3.5-6.1%), Flavobacterium (1.8-2.6%), Sphingobacterium
(1.4-1.6%) and Cellulophaga (1.4-2.0%), were members of Bacteroidetes
and likely associated with the degradation and turnover of organic
matter. The Marine Group I Archaea Nitrosopumilus was also detected.
Remarkably, eukaryotic green alga Bathycoccus, Ostreococcus and
Micromonas accounted for 8.8-15.2%, 3.6-4.9% and 2.1-3.1% of total read
counts, respectively, highlighting their potential roles in the
phytoplankton bloom after winter mixing.