Oceanic distribution of single-celled protosists

Single-celled protosists are key players in the world’s largest ecosystem through global biogeochemical cycling of energy and nutrients. Currently, there is a good understanding of their roles as primary producers and grazers yet in other aspects such as their life histories remain an overlooked area due to the challenges faced through culturing and sequencing. Seeleuthner et al., 2018, integrated single-celled genomics with metagenomics and metatranscriptomic sequence data to analyse the genome content and oceanic distribution of seven lineages of uncultured heterotrophic stramenopiles. Due to being highly abundant in temperate and tropical oceans the authors selected Marine stramenopile group 4 (MAST-4). Fundamentally the study found that each genome had a specific oceanic distribution linked to water temperature and depth. The conclusions of the study were limited by the data harvested from the TARA oceans project which used a singular time point per sample area resulting in a relatively low resolution of results. Despite this these findings provide the basis for a hypothesis of specialisation of niche species based on motility, nutrient range and trophic stages, in turn demonstrating the notion that heterotrophic marine protosists perform a diverse function in ocean ecology.

Seeleuthner, Y., Mondy, S., Lombard, V., Carradec, Q., Pelletier, E., Wessner, M., Leconte, J., Mangot, J., Poulain, J., Labadie, K., Logares, R., Sunagawa, S., de Berardinis, V., Salanoubat, M., Dimier, C., Kandels-Lewis, S., Picheral, M., Searson, S., Pesant, S., Poulton, N., Stepanauskas, R., Bork, P., Bowler, C., Hingamp, P., Sullivan, M., Iudicone, D., Massana, R., Aury, J., Henrissat, B., Karsenti, E., Jaillon, O., Sieracki, M., de Vargas, C. and Wincker, P. (2018). Single-cell genomics of multiple uncultured stramenopiles reveals underestimated functional diversity across oceans: Nature Communications, 9(1).