Targeted genomic analysis of a predominant uncultured marine pelagiphage-host model via microfluidics and semipermeable capsule technology

Microbes and their viruses drive central biogeochemical cycles on a global scale. Understanding the biology and ecology of virus–host interactions and their impact on ecosystems depends on our ability to develop tools that enable high-throughput screening of ecologically relevant, uncultured virus–host pairs. Viruses infecting Pelagibacterales, the predominant bacteria in surface oceans, have been studied through computational analyses and cultivation efforts. Here, we employ an accessible microfluidics and semi-permeable capsule (SPC) technology to investigate the uncultured pelagiphage vSAG 37-F6–host interactions since it is one of the most abundant and ubiquitous viruses in the marine virosphere. First, we validated this technology using cultured virus–host pairs. Then, marine single cells were microfluidically encapsulated in SPCs, lysed, whole-genome amplified, and screened using fluorescent polymerase chain reaction (PCR) for the presence of a hallmark gene of vSAG 37-F6. Data indicate that ~30% of the targeted cell population (cell fraction ≤0.45 μm) contained the virus vSAG 37-F6-like. A total of ~500 putatively infected cells were sorted, combined, and sequenced. Data showed that most reads (~60%) and assembled genome fragments (~85%) were identified as viral, indicating that the sorted host cells were likely in the final stages of infection. Two major viral clusters were detected: one corresponding to vSAG 37-F6 and another mixed viral cluster consisting of cyanophages, pelagiphages, and vibriophages. A significant proportion of total reads (~20%) were assigned to Pelagibacter spp. TMED287, a bacterium reported to be abundant in the Mediterranean Sea. This flexible microfluidic-SPC technology holds enormous potential for exploring uncultured microbial and viral communities across various perspectives and microbiology fields.

© The Author(s) 2025. Published by Oxford University Press on behalf of the International Society for Microbial Ecology. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.

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