Long-term warming associated with genetic changes in soil microbes
Click Here to Manage Email Alerts
WASHINGTON — Long-term warming is associated with genetic changes in soil microbes, "resulting in altered microbial response to the environment,” researchers reported at ASM Microbe.
The researchers investigated how rising temperatures might affect terrestrial microbes’ impact on the climate.
“I’m really interested in soil, the microbes in the soil, and whether they can act as self-reinforcing feedback for the climate system,” Kristen M. DeAngelis, PhD, an associate professor in the department of microbiology at the University of Massachusetts, said.
DeAngelis explained that all organisms, including those in soil, react to environmental stressors and stress in general, and that climate as a stressor could lead to microbial adaptation in soil organisms as they adapt to long-term warming, which could ultimately alter their genetic traits.
“This would result in irreversible and heritable changes to microbial traits and carbon cycling activities,” the authors wrote in their abstract.
To understand how soil microbes are adapting to climate warming, the researchers assessed bacteria isolated from a long-term field warming experiment in which soils were heated 5°C above the standard air temperatures for 30 years. They screened the isolates, focusing on members of dominant lineages or lineages that have been previously observed to be sensitive to warming, including Actinobacteria, Acidobacteria, and Alphaproteobacteria. The isolates were genotyped and analyzed for adaptation.
Overall, they found that Actinobacteria exposed to long-term warming had increased drought tolerance, growing more under dry conditions compared with isolates from controls. Additionally, after examining Alphaproteobactera exposed to long-term warming and measuring their temperature sensitivity of growth, the researchers grew isolates in liquid in 96 well plates and sequenced their genomes, revealing alterations in bacterial lineages from the heated plots of soil compared with controls.
Based on these findings, they concluded that bacteria in soil acquire new traits in response to chronic warming, including genomic signatures of adaptation.
“These genomic markers for adaptation support our hypothesis that long-term warming is associated with heritable changes in microbial traits, resulting in altered microbial response to the environment,” the authors wrote.