Antarctica is one of the driest, coldest places on Earth and long ago its soil microbes were largely dismissed as static or inactive, asleep in the harsh conditions - but new research has revealed that is decidedly not the case.
Led by scientists from Securing Antarctica's Environmental Future (SAEF) ARC Special Research Initiative based at Monash University in Melbourne, Australia, a new study has found that Antarctic microbes are in fact frequently acquiring useful genetic material from neighbouring organisms, including distantly related species, in a process known as 'horizontal gene transfer'.
Published in Nature Communications, the work showed that the practice of acquiring these genetic tools is widespread in Antarctic soils.
Lead author Yongyi Peng, a SAEF PhD Candidate at Monash University, said this may be because there is very little carbon or energy for cell division, which is how cells normally pass on their genetic information.
"In harsh environmental conditions, microbes tend to have smaller genomes because there is limited energy available. But they still need the essential functions required for survival. Frequent gene transfer between species can help them maintain those key biological processes," she said.
The analysis looked at horizontal gene transfer and selection patterns in all microbes living in soils from 16 Antarctic desert sites in the Mackay Glacier region, within the McMurdo Dry Valleys.
The research team found that, among soil microbes, energy-producing genes are transferred more often than expected compared with other genetic tools. In more temperate environments, energy genes are among the least frequently transferred.
According to Ms Peng, this tactic has likely evolved because it helps microbes harvest scarce resources from their harsh environment.
"Genes for aerotrophy - the consumption of atmospheric trace gases to provide energy, carbon and hydration - were among the most frequently identified, and these genes were also strongly selected, helping preserve their function over time." she said.
"Largely because aerotrophy is critical to microbial survival in Antarctica."
Co-author Dr Ry Holland, also from SAEF, said this horizontal gene transfer, combined with natural selection, offers a powerful framework for elucidating how microorganisms diversify and adapt in natural environments.
"This study is a big piece of the puzzle helping us understand how these dynamics shape metabolic traits in Antarctic soil microbes, which experience extremes of temperature, aridity, light, UV, salinity and nutrients," said Dr Holland.
"We hypothesize that these eco-evolutionary dynamics are of particular importance in Antarctica to overcome slow growth and turnover that would otherwise result in slow rates of adaptation."
It may also provide a key insight into how microbes will adapt and diversify in response to climate change.
