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Adaptation of superphylum Patescibacteria to groundwater - Easy Microbial Genomics

Home > Paper Highlights >  Adaptation of superphylum Patescibacteria to groundwater

Small and mighty: adaptation of superphylum Patescibacteria to groundwater environment drives their genome simplicity

Posted April 28, 2022

The newly defined superphylum Patescibacteria such as Parcubacteria (OD1) and Microgenomates (OP11) have been found to be ubiquitous in groundwater, sediment, lake and other aquifer environments. Recently, there has been increasing interest in this diverse group, including more than 20 candidate phyla (a significant portion of the candidate phylum radiation, CPR), as it refreshed our view of the tree of life. However, the adaptive traits that led to its popularity remain unknown.

The group of Dr. Zhou Jizhong from University of Oklahoma investigated the genomic features and metabolic pathways of Patescibacteria in groundwater through genome-resolved metagenomics analysis of > 600 Gbp of sequence data. They observed that, while members of Patescibacteria have larged reduced the genome sizes (~ 1 Mbp), functions essential for growth and reproduction, such as genetic information processing, were preserved. Surprisingly, they drastically reduced redundant and non-essential functions, including specific metabolic activities and stress response systems.

Patescibacteria have ultra-small cells and simplified membrane structures, including flagellar assemblies, transporters, and two-component systems. Despite the lack of CRISPR viral defenses, the bacteria may evade predation by deleting common membrane phage receptors and other alternative strategies, which may explain the low representation of prophage proteins in their genomes and the lack of CRISPR. By establishing links between bacterial characteristics and groundwater environmental conditions, their results provide important insights into the function and evolution of this CPR group.

In conclusion, they found that Patescibacteria simplified many functions while gaining advantages such as avoiding phage invasion to adapt to groundwater environments. The unique features including small genome size, ultra-small cell size and lack of CRISPR of this large lineage are bringing new insights into bacterial life. Their findings provide important insights into the adaptive mechanisms of the superphylum in groundwater environments and demonstrate a case where less is more, and small could be powerful.

The proposed adaptive mechanisms of Patescibacteria for surviving in groundwater environment

image source: Microbiome


Tian, R., Ning, D., He, Z. et al. Small and mighty: adaptation of superphylum Patescibacteria to groundwater environment drives their genome simplicity. Microbiome 8, 51 (2020).