Poorly protists and their viral infections

Little was known about marine viruses until the last decade as viral metagenomics improved allowing us to study their diversity and biogeography. However, the interaction between host and virus is still under studied, especially the interaction of viral infections on protists.  Using single cell genomics Castillo Y.M. et al. (2019) used un-cultured stramenopiles, collected by the Tara Oceans expedition, to carry out viral sequencing and analyse the virophages found.

Around 1-3 viral contigs were found in 37 of the 64 cells sequenced, showing that protists cells do contain viruses but the association between the host cell and virus was unable to be identified.  These viruses may have been engulfed by the cell, permanently part of the genome or be replicating within the cell.  >95% of viral sequences identified were found in only one stramenopile lineage with only 3 shared between lineages.  This suggests that viruses infecting protists are more specialist than those infecting eukaryotes when you compare with previous studies.

I think this study gives an important stepping-stone into viral-protist relationships and creates some base knowledge for further research on the interactions and importance of viruses within protist cells.

Castillo, Y. M., Mangot, J.F., Benites, L.F., Logares, R., Kuronishi, M., Ogata, H., Jaillon, O., Massana, R., Sebastian, M., Vaque, D. (2019). Assessing the viral content of uncultured picoeukaryotes in the global-ocean by single cell genomics. Molecular ecology, 28(28), 4272-4289

https://doi.org/10.1111/mec.15210