C-DI-GMP ROLE IN MANGANESE OXIDATION PROCESS IN THE ENVIRONMENTAL ISOLATE Pseudomonas resinovorans STRAIN MOB-513

PARRA, L; MARTELLI, E; PIAZZA, AINELÉN; JORGELINA OTTADO; GOTTIG, N.

Congreso; XVIII Congreso Samige; 2023

The presence of soluble manganese 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.Bioaugmentation of biological sand filters with Mn(II)-oxidizing bacteria (MOB) is used to increase Mn removal efficiencies from groundwater. The environmental isolate Pseudomonas resinovorans strain MOB-513 improves Mn groundwater removal.Interestingly, previous studies showed that this bacterium can oxidize Mn(II) only in the biofilm lifestyle and that c-di-GMP, a second messenger crucially involved in Pseudomonas biofilm formation, increases biofilm-formation and Mn(II)-oxidizing capabilities in MOB-513.To further investigate the role of c-di-GMP in Mn(II) oxidation, a transposon mutagenesis in MOB-513 was performed. A total of 30.000 transformants were obtained and the extreme phenotypes were chosen: 428 white, non-Mn(II)-oxidizing colonies and 284 dark brown, with a higher capacity of Mn(II) oxidation than MOB-513 wild type. The sequences affected for the transposon insertion were amplified by PCR and the products were purified and sequenced.Until this moment, 89 clones were sequenced and the sequences disrupted for the transposon were identified. Some of these mutants are related with the synthesis and degradation of c-di-GMP or response regulator related to this messenger, for example proteins involved in biofilm formation. The mutant clones were characterized by their biofilm formation, swimming and twitching motility capabilities compared to MOB-513 wild type. Also, q-RT-PCR assays were performed in order to study gene expression around the disrupted sequences.These results provide more information about the relationship between c-di-GMP signaling and Mn (II) oxidation in MOB-513. Future studies are necessary to understand more specifically the role of each gene in this process.