Acquisition of the arginine deiminase system benefits epiparasitic Saccharibacteria and their host bacteria in a mammalian niche environment

• DOI: 10.1073/pnas.2114909119
• Publication Date: 2022-01-06T21:05:16Z
• Authors: Jing Tian; Daniel R. Utter; Lujia Cen; Pu-Ting Dong; Wenyuan Shi; Batbileg Bor; Man Qin; Jeffrey S. McLean; Xuesong He
• Keywords: Mammals; 0301 basic medicine; 570; Mouth; Multidisciplinary; Saccharibacteria; Bacteria; Hydrolases; Microbiota; episymbiosis; Biological Sciences; Arginine; Adaptation, Physiological; Host Specificity; TM7; 03 medical and health sciences; oral microbiome; Actinomyces; Animals; Humans; arginine deiminase system; Symbiosis; Genome, Bacterial; Phylogeny

Significance The Candidate Phyla Radiation (CPR) is a large monophyletic lineage with poorly understood biology. Saccharibacteria are ultrasmall parasitic CPR bacteria with highly reduced genomes that have made the transition from an environmental origin to mammals. We tested the function and impact of the arginine deiminase system (ADS), an arginine catabolism pathway likely acquired by mammal-associated Saccharibacteria during their environment-to-mammal niche transition. We showed that the acquired ADS not only helped facilitate Saccharibacterial adaptation to mammals but also contributed to the establishment of cooperative episymbiotic interaction with their bacterial hosts within mammalian microbiomes. Our study provides experimental evidence demonstrating the importance of function acquired by Saccharibacteria during niche transition in facilitating their adaptation from the environment to a mammalian niche.