Four strains of Methylobacteriaceae discovered

Food grown outside of Earth requires a little additional support from bacteria to endure the rigors of space on deep-space missions. The latest discovery aboard the International Space Station (ISS) could now enable scientists to develop the “fuel” to help plants endure such stressful conditions.

Scientists collaborating with NASA have published the study findings in Frontiers in Microbiology, elaborating on the discovery and isolation of four bacterial strains from the Methylobacteriaceae family from various locations aboard the ISS across two consecutive flights.

Although one of the strains was identified as Methylorubrum rhodesianum, the other 3 were not discovered earlier and belong to a novel species. The rod-shaped, motile bacteria were given the names IIF1SW-B5, IIF4SW-B5, and IF7SW-B2T, where a genetic analysis revealed that they are closely associated with Methylobacterium indicum.

Methylobacterium species contribute to abiotic stress tolerance, plant growth promotion, nitrogen fixation, biocontrol activity against plant pathogens, and phosphate solubilization.

Potential for Mars missions

As a tribute to the renowned Indian biodiversity scientist Dr. Ajmal Khan, the research group has now proposed to name the novel species Methylobacterium ajmalii.

Dr. Kasthuri Venkateswaran (Venkat) and Dr. Nitin Kumar Singh of NASA’s Jet Propulsion Laboratory (JPL) commented on the discovery by noting that the strains might exhibit “biotechnologically useful genetic determinants” to help grow crops in space.

But further experimental biology is essential to prove that it is, in fact, a potential game-changer for space farming.

To grow plants in extreme places where resources are minimal, isolation of novel microbes that help to promote plant growth under stressful conditions is essential.”

Dr Kasthuri Venkateswaran and Dr Nitin Kumar Singh, Jet Propulsion Laboratory, NASA

Apart from JPL, other researchers working together on this discovery are from the University of Southern California, Los Angeles; Cornell University; and the University of Hyderabad in India.

NASA aims to take humans to the surface of Mars—and possibly beyond. Hence, the US National Research Council Decadal Survey suggests the space agency use the ISS as a “test-bed for surveying microorganisms,” stated Venkat and Singh.

“Since our group possesses expertise in cultivating microorganisms from extreme niches, we have been tasked by the NASA Space Biology Program to survey the ISS for the presence and persistence of the microorganisms,” they added.

Needless to say, the ISS is a cleanly-maintained extreme environment. Crew safety is the number 1 priority and hence understanding human/plant pathogens are important, but beneficial microbes like this novel Methylobacterium ajmalii are also needed.”

Dr Kasthuri Venkateswaran and Dr Nitin Kumar Singh, Jet Propulsion Laboratory, NASA

Expanding the ISS lab

As part of a current surveillance mission, eight locations on the ISS are being—and have been for the last 6 years—monitored for bacterial growths. Sample areas are where the crew assembles or where experiments are performed, for example, the plant growth chamber.

Although hundreds of bacterial samples obtained from the ISS have been studies so far, about 1,000 samples have been gathered from several other locations on the space station, awaiting a trip back to Earth where they can be analyzed.

Venkat and Singh added that the ultimate aim is to bypass this time-consuming process and prospectively find other novel strains with the help of molecular biology equipment created and demonstrated for the ISS.

Instead of bringing samples back to Earth for analyses, we need an integrated microbial monitoring system that collect, process, and analyze samples in space using molecular technologies.”

Dr Kasthuri Venkateswaran and Dr Nitin Kumar Singh, Jet Propulsion Laboratory, NASA

“This miniaturized ‘omics in space’ technology—a biosensor development—will help NASA and other space-faring nations achieve safe and sustainable space exploration for long periods of time,” concluded Venkat and Singh.