The rare biosphere contains microorganisms that present in low abundance. These rare microorganisms represent the majority of the Earth's biodiversity; they are responsible for ecosystem multifunctionality and act as the "seed bank" during ecological restoration.
However, the diversity and biogeography of rare microorganisms are still poorly understood in the terrestrial ecosystem.
A research group led by Prof. KONG Weidong from the Institute of Tibetan Plateau Research (ITP) of the Chinese Academy of Sciences compared the biogeography and the assembly mechanisms of rare and abundant bacteria across a 1200 km transect in the Tibetan Plateau.
The results demonstrated that both rare and abundant bacteria exhibited similar community structure changing patterns across the meadow-steppe-desert transect at both community composition and phylogeny levels. However, rare bacteria (72%) were more strongly influenced by stochasticity than abundant bacteria (57%).
The researchers found that environmental factors explained 41% of the community composition in rare bacteria, lower than that in abundant bacteria (80%). In contrast, environmental factors explained 36% of the community phylogeny in rare bacteria, higher than that in abundant bacteria (29%).
Geospatial distance and local environmental factors contributed equally to the community phylogeny of rare bacteria (11.5% and 11.9%, respectively), whereas the geospatial factors explained a larger proportion of the community phylogeny (22.1%) than local factors (11.3%) in abundant bacteria.
Furthermore, the community composition and phylogeny of abundant bacteria were decoupled during environmental changes. In contrast, these two were tightly coupled in rare bacteria. This suggests that abundant bacteria are better at maintaining ecological functions under environmental changes.
This research revealed the biogeography and community assembly of rare bacteria in terrestrial ecosystems, and provided novel insights into the functions of rare bacteria in maintaining ecosystem structural and functional integrity.
The study was published in
Environmental Microbiology. It was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences, the Key Program of the Chinese Academy of Sciences, and the National Natural Science Foundation of China.
