@misc{HertelSchoeneMittelstaedtetal., author = {Hertel, Robert and Sch{\"o}ne, Kerstin and Mittelst{\"a}dt, Carolin and Meißner, Janek and Zschoche, Nick and Collignon, Madeline and Kohler, Christian and Friedrich, Ines and Schneider, Dominik and Hoppert, Michael and Kuhn, Ramona and Schwedt, Inge and Scholz, Patricia and Poehlein, Anja and Martienssen, Marion and Ischebeck, Till and Daniel, Rolf and Commichau, Fabian M.}, title = {Characterization of glyphosate-resistant Burkholderia anthina and Burkholderia cenocepacia isolates from a commercial Roundup® solution}, series = {Environmental Microbiology Reports}, volume = {14}, journal = {Environmental Microbiology Reports}, number = {1}, issn = {1758-2229}, doi = {10.1111/1758-2229.13022}, pages = {70 -- 84}, abstract = {Roundup® is the brand name for herbicide solutions containing glyphosate, which specifically inhibits the 5-enolpyruvyl-shikimate-3-phosphate (EPSP) synthase of the shikimate pathway. The inhibition of the EPSP synthase causes plant death because EPSP is required for biosynthesis of aromatic amino acids. Glyphosate also inhibits the growth of archaea, bacteria, Apicomplexa, algae and fungi possessing an EPSP synthase. Here, we have characterized two glyphosate-resistant bacteria from a Roundup solution. Taxonomic classification revealed that the isolates 1CH1 and 2CH1 are Burkholderia anthina and Burkholderia cenocepacia strains respectively. Both isolates cannot utilize glyphosate as a source of phosphorus and synthesize glyphosate-sensitive EPSP synthase variants. Burkholderia. anthina 1CH1 and B. cenocepacia 2CH1 tolerate high levels of glyphosate because the herbicide is not taken up by the bacteria. Previously, it has been observed that the exposure of soil bacteria to herbicides like glyphosate promotes the development of antibiotic resistances. Antibiotic sensitivity testing revealed that the only the B. cenocepacia 2CH1 isolate showed increased resistance to a variety of antibiotics. Thus, the adaptation of B. anthina 1CH1 and B. cenocepacia 2CH1 to glyphosate did not generally increase the antibiotic resistance of both bacteria. However, our study confirms the genomic adaptability of bacteria belonging to the genus Burkholderia.}, language = {en} } @misc{WangWampGibhardtetal., author = {Wang, Mengyi and Wamp, Sabrina and Gibhardt, Johannes and Holland, Gudrun and Schwedt, Inge and Schmidtke, Kai-Uwe and Scheibner, Katrin and Halbedel, Sven and Commichau, Fabian M.}, title = {Adaptation of Listeria monocytogenes to perturbation of c-di-AMP metabolism underpins its role in osmoadaptation and identifies a fosfomycin uptake system}, series = {Environmental microbiology}, volume = {24}, journal = {Environmental microbiology}, number = {9}, issn = {1462-2920}, doi = {10.1111/1462-2920.16084}, pages = {4466 -- 4488}, abstract = {The human pathogen Listeria monocytogenes synthesizes and degrades c-di-AMP using the diadenylate cyclase CdaA and the phosphodiesterases PdeA and PgpH respectively. c-di-AMP is essential because it prevents the uncontrolled uptake of osmolytes. Here, we studied the phenotypes of cdaA, pdeA, pgpH and pdeA pgpH mutants with defects in c-di-AMP metabolism and characterized suppressor mutants restoring their growth defects. The characterization of the pdeA pgpH mutant revealed that the bacteria show growth defects in defined medium, a phenotype that is invariably suppressed by mutations in cdaA. The previously reported growth defect of the cdaA mutant in rich medium is suppressed by mutations that osmotically stabilize the c-di-AMP-free strain. We also found that the cdaA mutant has an increased sensitivity against isoleucine. The isoleucine-dependent growth inhibition of the cdaA mutant is suppressed by codY mutations that likely reduce the DNA-binding activity of encoded CodY variants. Moreover, the characterization of the cdaA suppressor mutants revealed that the Opp oligopeptide transport system is involved in the uptake of the antibiotic fosfomycin. In conclusion, the suppressor analysis corroborates a key function of c-di-AMP in controlling osmolyte homeostasis in L. monocytogenes.}, language = {en} } @misc{SchwedtSchoeneEckertetal., author = {Schwedt, Inge and Sch{\"o}ne, Kerstin and Eckert, Maike and Pizzinato, Manon and Winkler, Laura and Knotkova, Barbora and Richts, Bj{\"o}rn and Hau, Jann-Louis and Steuber, Julia and Mireles, Raul and Noda-Garcia, Lianet and Fritz, G{\"u}nter and Mittelst{\"a}dt, Carolin and Hertel, Robert and Commichau, Fabian M.}, title = {The low mutational flexibility of the EPSP synthase in Bacillus subtilis is due to a higher demand for shikimate pathway intermediates}, series = {Environmental Microbiology}, volume = {25}, journal = {Environmental Microbiology}, number = {12}, issn = {1462-2912}, doi = {10.1111/1462-2920.16518}, pages = {3604 -- 3622}, abstract = {Glyphosate (GS) inhibits the 5-enolpyruvyl-shikimate-3-phosphate (EPSP) synthase that is required for aromatic amino acid, folate and quinone biosynthesis in Bacillus subtilis and Escherichia coli. The inhibition of the EPSP synthase by GS depletes the cell of these metabolites, resulting in cell death. Here, we show that like the laboratory B. subtilis strains also environmental and undomesticated isolates adapt to GS by reducing herbicide uptake. Although B. subtilis possesses a GS-insensitive EPSP synthase, the enzyme is strongly inhibited by GS in the native environment. Moreover, the B. subtilis EPSP synthase mutant was only viable in rich medium containing menaquinone, indicating that the bacteria require a catalytically efficient EPSP synthase under nutrient-poor conditions. The dependency of B. subtilis on the EPSP synthase probably limits its evolvability. In contrast, E. coli rapidly acquires GS resistance by target modification. However, the evolution of a GS-resistant EPSP synthase under non-selective growth conditions indicates that GS resistance causes fitness costs. Therefore, in both model organisms, the proper function of the EPSP synthase is critical for the cellular viability. This study also revealed that the uptake systems for folate precursors, phenylalanine and tyrosine need to be identified and characterized in B. subtilis.}, language = {en} } @misc{SchwedtCollignonMittelstaedtetal., author = {Schwedt, Inge and Collignon, Madeline and Mittelst{\"a}dt, Carolin and Giudici, Florian and Rapp, Johanna and Meißner, Janek and Link, Hannes and Hertel, Robert and Commichau, Fabian M.}, title = {Genomic adaptation of Burkholderia anthina to glyphosate uncovers a novel herbicide resistance mechanism}, series = {Environmental Microbiology Reports}, volume = {15}, journal = {Environmental Microbiology Reports}, number = {6}, issn = {1758-2229}, doi = {10.1111/1758-2229.13184}, pages = {727 -- 739}, abstract = {Glyphosate (GS) specifically inhibits the 5-enolpyruvyl-shikimate-3-phosphate (EPSP) synthase that converts phosphoenolpyruvate (PEP) and shikimate-3-phosphate to EPSP in the shikimate pathway of bacteria and other organisms. The inhibition of the EPSP synthase depletes the cell of the EPSP-derived aromatic amino acids as well as of folate and quinones. A variety of mechanisms (e.g., EPSP synthase modification) has been described that confer GS resistance to bacteria. Here, we show that the Burkholderia anthina strain DSM 16086 quickly evolves GS resistance by the acquisition of mutations in the ppsR gene. ppsR codes for the pyruvate/ortho-Pi dikinase PpsR that physically interacts and regulates the activity of the PEP synthetase PpsA. The mutational inactivation of ppsR causes an increase in the cellular PEP concentration, thereby abolishing the inhibition of the EPSP synthase by GS that competes with PEP for binding to the enzyme. Since the overexpression of the Escherichia coli ppsA gene in Bacillus subtilis and E. coli did not increase GS resistance in these organisms, the mutational inactivation of the ppsR gene resulting in PpsA overactivity is a GS resistance mechanism that is probably unique to B. anthina.}, language = {en} }