Microdiverse bacterial clades prevail across Antarctic wetlands
[1];
[2];
[6]
- Universidad Nacional de San Martín, Buenos Aires (Argentina). Instituto Tecnológico de Chascomús (CONICET-UNSAM)
- Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
- Universidad Nacional de San Martín, Buenos Aires (Argentina). Instituto Tecnológico de Chascomús. Instituto de Investigación e Ingeniería Ambiental. (IIIA, CONICET-UNSAM)
- Univ. of Pretoria (South Africa). Centre for Microbial Ecology and Genomics (CMEG)
- Centre for Microbial Ecology and Genomics (CMEG), Department of Biochemistry, Genetics and Microbiology University of Pretoria Pretoria South Africa
- Consejo Superior de Investigaciones Cientificas (CSIC), Salamanca (Spain). Instituto de Recursos Naturales y Agrobiología de Salamanca (IRNASA)
Antarctica's extreme environmental conditions impose selection pressures on microbial communities. Indeed, a previous study revealed that bacterial assemblages at the Cierva Point Wetland Complex (CPWC) are shaped by strong homogeneous selection. Yet which bacterial phylogenetic clades are shaped by selection processes and their ecological strategies to thrive in such extreme conditions remain unknown. Here, we applied the phyloscore and feature-level βNTI indexes coupled with phylofactorization to successfully detect bacterial monophyletic clades subjected to homogeneous (HoS) and heterogenous (HeS) selection. Remarkably, only the HoS clades showed high relative abundance across all samples and signs of putative microdiversity. The majority of the amplicon sequence variants (ASVs) within each HoS clade clustered into a unique 97% sequence similarity operational taxonomic unit (OTU) and inhabited a specific environment (lotic, lentic or terrestrial). Our findings suggest the existence of microdiversification leading to sub-taxa niche differentiation, with putative distinct ecotypes (consisting of groups of ASVs) adapted to a specific environment. We hypothesize that HoS clades thriving in the CPWC have phylogenetically conserved traits that accelerate their rate of evolution, enabling them to adapt to strong spatio-temporally variable selection pressures. Variable selection appears to operate within clades to cause very rapid microdiversification without losing key traits that lead to high abundance. Variable and homogeneous selection, therefore, operate simultaneously but on different aspects of organismal ecology. The result is an overall signal of homogeneous selection due to rapid within-clade microdiversification caused by variable selection. It is unknown whether other systems experience this dynamic, and we encourage future work evaluating the transferability of our results.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- AC05-76RL01830
- OSTI ID:
- 2328510
- Report Number(s):
- PNNL-SA--192358
- Journal Information:
- Molecular Ecology, Journal Name: Molecular Ecology Journal Issue: 1 Vol. 33; ISSN 0962-1083
- Publisher:
- WileyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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