Marine viruses are the most abundant entities (107 viruses mL-1) and the main reservoir of genomic diversity in the oceans. Theyare key players in the marine microbial food webs, controlling the abundances and shaping the diversity of microbes, and thus im-pacting the biogeochemical cycles. Several questions have arisen since the discovery of the relevance of viruses in the marine en-vironment: who are they? How many are there? and especially, who infects whom? Nowadays, it is possible to count the viralabundances (e.g. through flow cytometry, epifluorescence microscopy, etc.), but there is still a large gap on knowing who infectswhom. Although the development of high throughput sequencing gives information on viral diversity and potential hosts, it is difficultto visualize each specific virus-host interaction. With that goal in mind, we are currently working with a technique called VirusFISH(Virus Fluorescent in situ Hybridization). With this technique, we are able to visualize, thanks to fluorescence microscopy, the inter-actions between viruses and their eukaryotic hosts at different stages over time. Also, we are able to detect and count a specificvirus within the natural community. How does it work? We design and synthetize several fluorescently labeled probes (~10 DNAmolecules of 300bp length each), that will specifically attach to the genome of our virus of interest. Thus, we can monitor the timingand magnitude of infections in natural microbial communities, and understand the impact of the virus in the abundance and functionof its host

1st Iberian Ecological Society Meeting (2019); XIV Congreso Nacional de la Asociación Española de Ecología Terrestre (AEET), Ecology: an integrative science in the Anthropocene, 4-7 February 2019, Barcelona, Spain

Peer Reviewed