{"doi":"10.1128/mbio.00916-25","title":"c-di-GMP is required for swarming in <i>E. coli</i> , producing colanic acid that acts as surfactant","abstract":"ABSTRACT Many bacteria use flagella to swim individually through bulk liquid or swarm collectively over a semi-solid surface. In Escherichia coli , c-di-GMP inhibits swimming via the effector protein YcgR. We show in this study that, contrary to its effect on swimming, a certain threshold level of c-di-GMP is required for swarming. Gene expression profiles first indicated that several c-di-GMP synthases —dgcJ , dgcM , and dgcO —were upregulated during swarming. Of these, we found DgcO to play a critical role in promoting the production of colanic acid—one of the three major exopolysaccharides in E. coli . DgcO has been reported to increase poly-β-1,6-N-acetylglucosamine (PGA) synthesis in E. coli as well. We show that colanic acid has hitherto-unknown surfactant properties that are expected to aid swarming. IMPORTANCE It is well established that, in bacteria, c-di-GMP inhibits flagella-driven motility at various points in the pathway. Concomitantly, elevated c-di-GMP levels induce the expression and synthesis of a variety of exopolysaccharides that enmesh the bacteria in a biofilm, thereby also interfering with the flagella function. This study reports the surprising finding that, in Escherichia coli , the exopolysaccharide colanic acid is required to enable surface navigation and that the diguanylate cyclase DgcO is employed for this purpose. For surface navigation, there appears to be a sweet spot where c-di-GMP levels are just right to produce polysaccharides that can serve as surfactants and wetting agents rather than promote the formation of biofilms.","journal":"mBio","year":2025,"id":544069,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":1,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9618,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2025-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1433921,"name":"Marta Pérez","orcid":"0000-0002-1059-3677","position":1,"is_corresponding":false},{"id":1434365,"name":"Rebecca Holzel","orcid":null,"position":2,"is_corresponding":false},{"id":300722,"name":"Rasika M. Harshey","orcid":"0000-0002-2785-0879","position":3,"is_corresponding":false},{"id":889215,"name":"YuneSahng Hwang","orcid":"0000-0002-1816-9416","position":0,"is_corresponding":true}],"reference_count":71,"raw_metadata":null,"created_at":"2026-07-19T02:53:08.338070Z","pmid":"40326769","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}