Abstract
The Cape Verde islands are part of the African Sahelian arid belt that possesses an erratic rain pattern prompting the need for water reservoirs, which are now critical for the country’s sustainability. Worldwide, freshwater cyanobacterial blooms are increasing in frequency due to global climate change and the eutrophication of water bodies, particularly in reservoirs. To date, there have been no risk assessments of cyanobacterial toxin production in these man-made structures. We evaluated this potential risk using 16S rRNA gene amplicon sequencing and full metagenome sequencing in freshwater reservoirs of Cape Verde. Our analysis revealed the presence of several potentially toxic cyanobacterial genera in all sampled reservoirs. Faveta potentially toxic and bloom-forming Microcystis sp., dominated our samples, while a Cryptomonas green algae and Gammaproteobacteria dominated Saquinho and Poilão reservoirs. We reconstructed and assembled the Microcystis genome, extracted from the metagenome of bulk DNA from Faveta water. Phylogenetic analysis of Microcystis cf. aeruginosa CV01’s genome revealed its close relationship with other Microcystis genomes, as well as clustering with other continental African strains, suggesting geographical coherency. In addition, it revealed several clusters of known toxin-producing genes. This survey reinforces the need to better understand the country’s microbial ecology as a whole of water reservoirs on the rise.
Highlights
The available freshwater in the African archipelago of Cape Verde (DMS coordinatesN, 23◦ 360 18.6200 W) does not cover its needs
The dominant species from one of the reservoirs was identified as a M. aeruginosa strain through phylogenetic studies, placing it closer to other strains collected in continental Africa
M. cf. aeruginosa CV01 genome revealed that it can produce toxins, and a potential risk of toxin production can exist in Cape Verdean reservoirs
Summary
Toxins 2018, 10, 186 creating conditions for eutrophication and exponential growth of microalgae These algal blooms have deleterious impacts on public health, water quality, and environmental issues, as well as economic costs due to bottom anoxia, release of noxious products, and toxic metabolites [2,3]. We were able to reconstruct, for the first time, the full genome of a potentially toxic cyanobacterium from Cape Verde, based on the full metagenome sequencing data of Faveta reservoir Analysis of this genome revealed the presence of genetic machinery used to synthesize cyanotoxins. The results of our biodiversity survey, phylogenetic analysis, and genome reconstruction lead us to conclude that toxin risk is a reality and a potential future threat in these reservoirs
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
