A new Tel Aviv University (TAU) study has identified about 100,000 new types of previously unknown viruses, a ninefold increase in the amount of RNA viruses known to science until now. These viruses were discovered in global environmental data from soil samples, oceans, lakes, and a variety of other ecosystems. The researchers believe that their discovery may help in the development of anti-microbial drugs and in protecting against agriculturally harmful fungi and parasites.

The study was led by doctoral student Uri Neri under the guidance of Professor Uri Gophna of the Shmunis School of Biomedicine and Cancer Research in TAU’s George S. Wise Faculty of Life Sciences. The research was published on September 28, 2022, in Cell, and comprised data collected by more than a hundred scientists around the world.

Viruses are genetic parasites that must infect a living cell in order to replicate their genetic information, produce new viruses, and complete their infection cycle. Some viruses, such as the coronavirus, are disease-causing agents that can cause harm to humans, but the vast majority of viruses do not harm us.

Neri says that the study used new computational technologies to mine genetic information collected from thousands of different sampling points around the world, such as oceans, soil, sewage, and geysers. The researchers developed a sophisticated computational tool that distinguishes between the genetic material of RNA viruses and that of their hosts and used it to analyze the data. The discovery allowed the researchers to reconstruct how the viruses underwent diverse acclimation processes throughout their evolutionary development in order to adapt to different hosts. In analyzing their findings, the researchers were able to identify viruses suspected of infecting various pathogenic microorganisms, thus opening up the possibility of using viruses to control them.

“The system we developed makes it possible to perform in-depth evolutionary analyses and to understand how the various RNA viruses have developed throughout evolutionary history,” Professor Gophna says. “One of the key questions in microbiology is how and why viruses transfer genes between them. We identified a number of cases in which such gene exchanges enabled viruses to infect new organisms. Furthermore, compared to DNA viruses, the diversity and roles of RNA viruses in microbial ecosystems are not well understood.

“In our study, we found that RNA viruses are not unusual in the evolutionary landscape and, in fact, that in some aspects they are not that different from DNA viruses. This opens the door for future research, and for a better understanding of how viruses can be harnessed for use in medicine and agriculture.”

The research was conducted in collaboration with the US-based research bodies NIH and JGI, as well as the Pasteur Institute in France.