Open AccessOccurrence and diversity of viruses associated with cyanobacterial communities in a Brazilian freshwater reservoir
Author(s) -
Leandro de Oliveira Santos,
Iamê Alves Guedes,
Sandra Maria Feliciano de Oliveira e Azevedo,
Amílcar Pacheco
Publication year - 2021
Publication title -
brazilian journal of microbiology
Language(s) - English
Resource type - Journals
eISSN - 1678-4405
pISSN - 1517-8382
DOI - 10.1007/s42770-021-00473-8
Subject(s) - prochlorococcus , microcystis , metagenomics , cyanobacteria , biology , synechococcus , siphoviridae , phytoplankton , microcystis aeruginosa , ecology , bacteriophage , bacteria , gene , genetics , escherichia coli , nutrient
As part of the phytoplankton of marine and freshwater environments around the world, cyanobacteria interact with viruses (cyanophages) that affect their abundance and diversity. Investigations focusing on cyanophages co-occurring with freshwater cyanobacteria are scarce, particularly in Brazil. The aim of this study was to assess the diversity of cyanophages associated with a Microcystis-dominated cyanobacterial bloom in a tropical reservoir. Samples were processed as viral fractions of water and cellular fractions, and temporal fluctuations in the abundance of Ma-LMM01-type cyanophages and their Microcystis hosts were determined by qPCR. We applied shotgun metagenomics to obtain a wider characterization of the cyanophage community. During the study period, Microcystis gene copies were quantified in all cellular fractions, and the copy number of the Ma-LMM01 phage gene tended to increase with host abundance. Metagenomic analysis demonstrated that Caudovirales was the major viral order associated with the cyanophage families Myoviridae (34-88%), Podoviridae (3-42%), and Siphoviridae (6-23%). The metagenomic analysis results confirmed the presence of Microcystis cyanophages in both viral and cellular fractions and demonstrated a high relative abundance of picocyanobacteria-related viruses and Prochlorococcus (36-52%) and Synechococcus (37-50%) phages. For other main cyanobacterial genera, no related cyanophages were identified, which was probably due to the scarce representation of cyanophage sequences in databanks. Thus, the studied reservoir hosted a diverse cyanophage community with a remarkable contribution of phages related to picoplanktonic cyanobacteria. These results provide insights that motivate future sequencing efforts to assess cyanophage diversity and recover complete genomes.