The menagerie of bacterial and fungal species that live among us is growing more and more, and this is no exception in low-gravity 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 places on 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 top panel of the ISS research stations, the second was found in the dome, and the third was found on the surface of the dining table; the fourth was found in an old HEPA filter returned to Earth in 2011.
The four strains belong to a family of bacteria found in soil and freshwater; they are involved in nitrogen fixation, plant growth and can help stop plant pathogens. Basically, there are good bacteria to have them around if you grow things.
You might be wondering what these soil bacteria did up to the ISS, but astronauts living on the space station have been cultivating small amounts of food for years, so it’s no surprise that we’ve found microbes related to the ISS on board. plants.
One of the strains, the finding of the HEPA filter, was identified as a well-known species called Methylorubrum rhodesianum. The other three were sequenced and found to belong to the same species that was not previously identified and the strains were named IF7SW-B2T, IIF1SW-B5, and IIF4SW-B5.
The team, led by Southern California University geneticist Swati Bijlani, has proposed calling the new species Methylobacterium ajmalii after Ajmal Khan, a renowned Indian biodiversity scientist. This new finding is also closely related to an already known species called M. indica.
“To grow plants in extreme places where resources are minimal, it is essential to isolate new microbes that help promote plant growth under stressful conditions,” two of the team, Kasthuri Venkateswaran, said in a press release. and Nitin Kumar Singh of NASA JPL.
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 set of genome sequences of these three ISS strains presented here will allow comparative genomic characterization of ISS isolates with their Earth counterparts in future studies,” the team writes in their study.
“This will further aid in the identification of 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 in roots and shoots. .
There is much more research to be done here: researchers acknowledge that they have barely scratched the surface of microbial diversity at the space station. About 1,000 samples have already been collected at the ISS, but they are still waiting for a trip back to Earth.
Imagine the exciting space-distance microbes we have yet to discover.
The research has been published in Frontiers in Microbiology.