Viruses are well known for their ability to hijack host cells and make them do their bidding, namely replicating themselves before bursting out in order to hunt down more unlucky victims. One virus, however, has been found to help its host cell, reprogramming it to be more efficient at uptaking nutrients.
The virus in question is one that infects marine plankton, which are major biogeochemists of the ocean. The tiny organisms take up nutrients washed into the oceans from the land and released by fish, mammals, and birds as they go about their business. They are also major carbon sinks, as when they die they sink to the bottom of the ocean, trapping the carbon in the depths.
The fact that a virus has been found to influence this process of nutrient uptake in plankton could have implications as to how carbon is absorbed and stored in our oceans.
One of the biggest limiting factors to the growth of plankton is the availability of phosphorous and nitrogen. Therefore, it was a surprise to researchers from the University of Exeter when they found that when a plankton species known as Ostreococcus tauri gets infected with a specific virus, it actually gets an additional ammonium transporter on its surface. This allows the green algae to more efficiently take up nitrogen.
This sounds like it would be a great advantage to the plankton it infected, and it is – in the short term at least. The newly added protein gives the organism an advantage over other uninfected plankton, which are outcompeted as the O. tauri take up more of the nitrogen. The increase in growth of the infected plankton is also an advantage to the virus, which is able to rapidly multiply within it, until it then needs to spread.
“This is beneficial to the virus in terms of its own reproduction – and when the virus is ready, it kills the cell and releases more of the virus to infect others,” says Professor Thomas Richards, who co-authored the research published in the Proceedings of the National Academy of Sciences, in a statement.
Not only that, but it seems that the virus has at some point stolen the piece of DNA that codes for the ammonium transporter protein from a species of phytoplankton and repurposed it for its use on green algae.
Normally, when we think of ecology, we consider controlling factors such as nutrient availability or predation. But this virus is seemingly blurring these lines. This has implications for how we now look at these processes, particularly within a marine setting, and could influence marine nutrient cycles.