The management of the bacterial and fungal species that live among us is constantly growing – and this is no exception in lightweight environments, such as the International Space Station (ISS).
Researchers in the United States and India working with NASA have now discovered four strains of bacteria that live in different parts of the ISS – three of which were, until now, completely unknown to science.
Three of the four strains were isolated in 2015 and 2016 – one was found on a panel above the ISS research stations, the second was found in the Dome, the third was found on the table surface; the fourth was found in an old HEPA filter returned to Earth in 2011.
All four strains belong to a family of bacteria found in soil and fresh water; are involved in nitrogen fixation, plant growth and can help stop plant pathogens. Basically, good bacteria to have around if you grow things.
You may be wondering what such bacteria do in the soil up to the ISS, but astronauts living on the space station have been growing small amounts of food for years, so it’s no surprise that we found plant-related microbes on board.
One of the strains – the discovery of the HEPA filter – has been identified as a known species called Methylorubrum rhodesianum. The other three were sequenced and found to all belong to the same species, not previously identified, and the strains were named IF7SW-B2T, IIF1SW-B5 and IIF4SW-B5.
The team, led by geneticist University of Southern California Swati Bijlani, proposed naming the new species Methylobacterium ajmalii after Ajmal Khan, a renowned Indian biodiversity scientist. This new discovery is also closely related to an already known species called M. indica.
“In order to grow plants in extreme places where resources are minimal, isolating new microbes that help promote plant growth under stress is essential,” explained two team members, Kasthuri Venkateswaran and Nitin Kumar Singh of NASA JPL, in -a press release.
Given that we already know that these microbes can survive the harsh conditions of the ISS, the team put the four strains through genetic analysis to look for genes that could be used to help promote plant growth.
“The entire genomic sequence of these three ISS strains reported here will allow comparative genomic characterization of ISS isolates with Earth counterparts in future studies,” the team wrote in their study.
“This will further help identify the genetic determinants that could be responsible for promoting plant growth under microgravity conditions and contribute to the development of self-sustaining plant crops for long-term space missions in the future.”
The researchers found that one of the ISS strains – IF7SW-B2T – had promising genes involved in plant growth, including a gene for an essential enzyme for cytokinin, which promotes cell division into roots and shoots.
There is much more research to be done here – researchers acknowledge that they have barely scratched the surface of microbial diversity on the space station. About 1,000 samples have already been collected on the ISS, but it is still waiting for a trip back to Earth.
Imagine the interesting space microbes that we have not yet discovered!
The research was published in Frontiers in microbiology.