Identification of molecular pathways underlying Mn(II) oxidation in Pseudomonas resinovorans

ABSTRACT: The presence of Mn(II) in groundwater, a common source of drinking water, is a cause of water quality impairment, interfering with its disinfection, causing operation problems, and affecting human health. Purification of groundwater containing Mn(II) plays an important role in environmental and social safety. The typical method for Mn(II) removal is based on bacterial oxidation of metals to form insoluble oxides that can be filtered out of the water. Evidence of reducing the start-up periods and enhancing Mn removal efficiencies through bioaugmentation with appropriate biofilm-forming and Mn(II)-oxidising bacteria (MOB) has emerged. However, the regulation of bacterial Mn(II) oxidation remains a fundamental question in environmental microbiology, with direct implications for the optimisation of bioremediation strategies. Here, an environmental isolate of Pseudomonas resinovorans strain MOB-513 was used as a model to investigate the genetic network underlying Mn(II) oxidation. To this end, we performed a random transposon mutagenesis screen and characterised mutants with abolished or enhanced Mn(II)-oxidising capacity. Given that the largest fraction of insertions mapped to genes required for Type IV pilus biogenesis, c-di-GMP signalling, and biofilm formation, we focused on two non-oxidising mutants: pilC and algR. PilC is a core component of Tfp biogenesis, while AlgR is a response regulator that controls pilus gene expression and biogenesis in other Pseudomonas spp. We further examined two mutants with potential effects on c-di-GMP metabolism or regulation. The first was the non-oxidising mutant disrupted in hk2948, an uncharacterised histidine kinase that may influence intracellular c-di-GMP levels via its association with the adjacent GGDEF/EAL-domain gene rr2947. The second mutant showed a hyper-oxidising phenotype with a transposon insertion in the promoter region of a gene encoding the putative diguanylate cyclase, DGC4077. The non-oxidising mutants were designated as MOB-513-pilC::Tn, MOB-513-algR::Tn, and MOB-513-hk2948::Tn and the hyper-oxidising strain was named MOB-513-dgc4077p::Tn. To investigate the physiological changes associated with transposon insertions in MOB-513, we conducted a comparative proteomic analysis between MOB-513 WT and MOB-513-pilC::Tn; MOB-513-algR::Tn; MOB-513-hk2948::Tn; and MOB-513-dgc4077::Tn.

INSTRUMENT(S):

ORGANISM(S): Pseudomonas Populi

TISSUE(S): Cell Culture

SUBMITTER: Ainelen Piazza  

LAB HEAD: Natalia Gottig

PROVIDER: PXD075883 | Pride | 2026-10-19

REPOSITORIES: Pride