Toward quantifying the adaptive role of bacterial pangenomes during environmental perturbations.
Roth E ConradTomeu ViverJuan F GagoJanet K HattStephanus N VenterRamon Rosselló-MóraKonstantinos T KonstantinidisPublished in: The ISME journal (2021)
Metagenomic surveys have revealed that natural microbial communities are predominantly composed of sequence-discrete, species-like populations but the genetic and/or ecological processes that maintain such populations remain speculative, limiting our understanding of population speciation and adaptation to perturbations. To address this knowledge gap, we sequenced 112 Salinibacter ruber isolates and 12 companion metagenomes from four adjacent saltern ponds in Mallorca, Spain that were experimentally manipulated to dramatically alter salinity and light intensity, the two major drivers of this ecosystem. Our analyses showed that the pangenome of the local Sal. ruber population is open and similar in size (~15,000 genes) to that of randomly sampled Escherichia coli genomes. While most of the accessory (noncore) genes were isolate-specific and showed low in situ abundances based on the metagenomes compared to the core genes, indicating that they were functionally unimportant and/or transient, 3.5% of them became abundant when salinity (but not light) conditions changed and encoded for functions related to osmoregulation. Nonetheless, the ecological advantage of these genes, while significant, was apparently not strong enough to purge diversity within the population. Collectively, our results provide an explanation for how this immense intrapopulation gene diversity is maintained, which has implications for the prokaryotic species concept.
Keyphrases
- genome wide
- genome wide identification
- escherichia coli
- human health
- genetic diversity
- climate change
- bioinformatics analysis
- genome wide analysis
- dna methylation
- healthcare
- microbial community
- copy number
- risk assessment
- transcription factor
- gene expression
- single cell
- cross sectional
- cystic fibrosis
- blood brain barrier
- pseudomonas aeruginosa
- antibiotic resistance genes
- high intensity
- anaerobic digestion
- life cycle