Biologists have found four bacterial strains of the Methylobacteriaceae family in surface samples collected from the International Space Station (ISS) during flight experiments with Microbial Tracking-1.
Transmission electron micrographs showing the general cell morphology of Methylobacterium jeotgali. Image Credit: Aslam et al., doi: 10.1099 / ijs.0.64625-0.
Dr Kasthuri Venkateswaran of NASA’s Jet Propulsion Laboratory and colleagues analyzed samples collected during Microbial Tracking-1 flight experiments during 2015 and 2016.
“As part of an ongoing microbial detection experiment on the ISS, eight sites are being monitored for bacterial growth, and this has been for the past six years,” they explained.
“These sample areas include where the crew meets or where experiments are performed, such as the plant growth room.”
The researchers isolated four Methylobacterium strains – indicated as IF7SW-B2T, IIF1SW-B5, IIF4SW-B5 and I1-R3 – from the samples.
Of these, the first three strains were assigned to a new species named Methylobacterium ajmalii, while the fourth was identified as Methylorubrum rhodesianum.
‘Members of the Methylobacterium genus are gram-negative, rod-shaped bacteria, ”said the scientists.
“The genus consists of 45 recognized species, which are ubiquitous in a wide variety of habitats, including air, soil, freshwater and sediments, and can exist in free form or with plant tissues.”
‘Methylobacterium species are involved in nitrogen fixation, soluble phosphates, abiotic stress tolerance, promoting plant growth and biocontrol against plant pathogens, ”they added.
‘For example, a recent discovery Methylobacterium sp. It has been observed that 2A results in a higher density of side roots in grafted potato crops, even under salt stress conditions, compared to control plants not inoculated with the bacteria; it has also been found to exhibit biocontrol activity against various plant pathogens. ”
According to the team, the newly isolated strains may possess ‘biotechnologically useful genetic determinants’ for the growth of crops in space.
However, further experimental biology is needed to prove that it is indeed a potential game changer for space farming.
“To grow plants in extreme places where there are minimal resources, isolation of new microbes is essential to promote plant growth under stressful conditions,” the authors said.
The findings appear in the journal Boundaries in microbiology.
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Swati Bijlani et al. Methylobacterium ajmalii sp. nov., Isolated from the International Space Station. Front. Microbial, published online on March 15, 2021; doi: 10.3389 / fmicb.2021.639396