JUN 01, 2020 8:14 AM PDT

The Most Common Marine Microbe Has a Virus in Its Genome

WRITTEN BY: Carmen Leitch

Single-celled ocean microbes known as Pelagibacter or SAR11 make up about 25 percent of the plankton on the planet. They might be the most common bacteria in the world. The vast numbers of microorganisms in the world have to compete for resources, and these dominant SAR11 bacteria have very been good at it. Researchers have known that SAR11 can host viruses, and this skill might be the secret to its success. Scientists have now learned more about a unique virus carried in the SAR11 genome. The virus is usually dormant, but it can activate and infect other cells, bringing some of the host genetic material along. The findings have been reported in Nature Microbiology.

Pelagibacter / Credit: NOAA / Ocean Exploration and Research

"Many bacteria have viruses that exist in their genomes. But people had not found them in the ocean's most abundant organisms," said the co-lead study author Robert Morris, a University of Washington associate professor of oceanography. "We suspect it's probably common, or more common than we thought—we just had never seen it."

Unlike viruses that infect a host cell to produce more viral particles, this virus gets copied along with the host cell genome, while it can also replicate and exit the cell to infect others. This research found that up to three percent of SAR11 microbes are infected but end up splitting open. That is a higher percentage than other viruses that reside in their host's genome, and maintains a large amount of free-floating viral particles to infect other cells.

"There are ten times more viruses in the ocean than there are bacteria," Morris said. "Understanding how those large numbers are maintained is important. How does a virus survive? If you kill your host, how do you find another host before you degrade?"

This research may also help us learn more about host-virus interactions in general.

"If you study a system in bacteria, that is easier to manipulate, then you can sort out the basic mechanisms," Morris said. "It's not too much of a stretch to say it could eventually help in biomedical applications."

For this work, co-lead study author Kelsy Cain gathered samples of SAR11 off the coast of Oregon. The microbes were then grown in the lab and a strain was sequenced. But a virus was getting in the way of their sequencing results.

"In the past, we got a full genome, first try," Morris said. "This one didn't do that, and it was confusing because it's a very small genome."

"When we went to grow the NP2 control culture, lo and behold, there was another virus. It was surprising how you couldn't get away from a virus," said Cain.

Cain found that when SAR11 is deprived of nutrients, the cells they infect burst open more often. The researchers suggested that since bacterial genes move out of the cell with the virus, it may be helping SAR11 keep a competitive advantage over other microbes in a challenging environment.

"We want to understand how that has contributed to the evolution and ecology of life in the oceans," Morris said.

Sources: Phys.org via University of Washington, Nature Microbiology

About the Author
  • Experienced research scientist and technical expert with authorships on 28 peer-reviewed publications, traveler to over 60 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
MAY 09, 2020
Clinical & Molecular DX
Rapid, Efficient COVID-19 Diagnostic Method Relies on Magnetic Beads
MAY 09, 2020
Rapid, Efficient COVID-19 Diagnostic Method Relies on Magnetic Beads
The pandemic virus SARS-CoV-2 has spread widely, and a lack of testing has been a serious problem.
MAY 25, 2020
Microbiology
Assessing the Risk of COVID-19 Posed by Various Summer Activities
MAY 25, 2020
Assessing the Risk of COVID-19 Posed by Various Summer Activities
While we know a lot more about the pandemic virus SARS-CoV-2 and the illness it causes, COVID-19, there are still many u ...
MAY 27, 2020
Cell & Molecular Biology
A Deeper Understanding of How Some Bacterial Toxins Interact With Cells
MAY 27, 2020
A Deeper Understanding of How Some Bacterial Toxins Interact With Cells
The surfaces of cells are decorated with receptors, and the interactions between receptors and their binding partners ar ...
JUN 30, 2020
Microbiology
Researchers Find a Flu They Say Has the Potential to Cause a Pandemic
JUN 30, 2020
Researchers Find a Flu They Say Has the Potential to Cause a Pandemic
The world's attention is on a virus right now - the pandemic coronavirus that causes COVID-19. But researchers are still ...
JUL 07, 2020
Microbiology
Why Some Are Naturally Better at Preventing Urinary Tract Infections
JUL 07, 2020
Why Some Are Naturally Better at Preventing Urinary Tract Infections
Urinary tract infections can be very painful and can cause nausea, chills, and fever. A pathogenic strain of E. coli is ...
AUG 11, 2020
Cell & Molecular Biology
New Microscopy Tools Reveal More About the Role of Actin
AUG 11, 2020
New Microscopy Tools Reveal More About the Role of Actin
Cells rely on a network of tiny filaments to give them form and support their structure. One crucial filament is a prote ...
Loading Comments...