Plasmalogen, a glycerophospholipid crucial for acid tolerance and colonization.

Unlabelled: Plasmalogen is a specific glycerophospholipid present in both animal and bacterial organisms. It plays a crucial function in eukaryotic cellular processes and is closely related to several human diseases, including neurological disorders and cancers. Nonetheless, the precise biological role of plasmalogen in bacteria is not well understood. In this study, we identified SMU_438c as the enzyme responsible for plasmalogen production in under anaerobic conditions. The heterologous expression of SMU_438c in a plasmalogen-negative strain, , resulted in the production of plasmalogen, indicating that this enzyme is sufficient for plasmalogen production. Additionally, the plasmalogen-deficient exhibited significantly lower acid tolerance and diminished its colonization in flies compared to the wild-type strain and complemented strain. In summary, our data suggest that plasmalogen plays a vital role in bacterial stress tolerance and colonization.

Importance: This study sheds light on the biological role of plasmalogen, a specific glycerophospholipid, in bacteria, particularly in . Plasmalogens are known for their significant roles in eukaryotic cells and have been linked to human diseases like neurological disorders and cancers. The enzyme SMU_438c, identified as essential for plasmalogen production under anaerobic conditions, was crucial for acid tolerance and colonization in by , underscoring its importance in bacterial stress response and colonization. These findings bridge the knowledge gap in bacterial physiology, highlighting plasmalogen's role in microbial survival and offering potential insights into microbial pathogenesis and host-microbe interactions.