MliR, a Novel MerR-like Regulator of Iron Homeostasis, Impacts Metabolism, Membrane Remodeling and Cell Adhesion in the Marine Bacteroidetes Bizionia argentinensis.

PELLIZZA LEONARDO; BIALER, MG; SIEIRA RODRIGO; ARAN, MARTÍN

Congreso; IV LAMPS MEETING.; 2022

LAMPS

The central role of iron in bacteria makes it a determinant of pathogenesis, invasiveness andsurvival. Significant progress has been made towards the regulation of iron metabolism in modelorganisms. However, mechanisms of iron homeostasis in Bacteroidetes, one of the dominant phylain animal gut, soil and oceans, remain largely unknown. Here, we identified a novel transcriptionalregulator of the MerR superfamily (MliR), phylogenetically unrelated to cognate Fur proteins,involved in iron homeostasis in the marine bacterium Bizionia argentinensis JUB59 and widelyconserved in bacteria from a variety of environments. This regulator was named MliR (MerR-like ironresponsive Regulator). Deletion of the mliR gene led to decreased cell growth, increased celladhesion and filamentation. Genome-wide transcriptomic analysis showed that genes associatedwith iron homeostasis were downregulated in mliR-deletion mutant. Through NMR-basedmetabolomics, ICP-MS, fluorescence microscopy and biochemical analysis we evaluated metabolicand phenotypic changes associated with mliR deletion.The findings presented here bring together transcriptional regulation, energy metabolism,membrane remodeling and cell adhesion, providing insights into the global response to ironavailability that may raise interest in microbiology in general.