title: Peptidoglycan metabolism is controlled by the WalRK (YycFG) and PhoPR two-component systems in phosphate-limited Bacillus subtilis cells.
abstract: In Bacillus subtilis, the WalRK (YycFG) two-component system controls peptidoglycan metabolism in exponentially growing cells while PhoPR controls the response to phosphate limitation. Here we examine the roles of WalRK and PhoPR in peptidoglycan metabolism in phosphate-limited cells. We show that B. subtilis cells remain viable in a phosphate-limited state for an extended period and resume growth rapidly upon phosphate addition, even in the absence of a PhoPR-mediated response. Peptidoglycan synthesis occurs in phosphate-limited wild-type cells at approximately 27% the rate of exponentially growing cells, and at approximately 18% the rate of exponentially growing cells in the absence of PhoPR. In phosphate-limited cells, the WalRK regulon genes yocH, cwlO(yvcE), lytE and ydjM are expressed in a manner that is dependent on the WalR recognition sequence and deleting these genes individually reduces the rate of peptidoglycan synthesis. We show that ydjM expression can be activated by PhoP approximately P in vitro and that PhoP occupies its promoter in phosphate-limited cells. However, iseA(yoeB) expression cannot be repressed by PhoP approximately P in vitro, but can be repressed by non-phosphorylated WalR in vitro. Therefore, we conclude that peptidoglycan metabolism is controlled by both WalRK and PhoPR in phosphate-limited B. subtilis cells.
authors.affiliation: Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland.
authors.forename: Paola
authors.initials: P
authors.lastname: Bisicchia
authors.forename: Efthimia
authors.initials: E
authors.lastname: Lioliou
authors.forename: David
authors.initials: D
authors.lastname: Noone
authors.forename: Letal I
authors.initials: LI
authors.lastname: Salzberg
authors.forename: Eric
authors.initials: E
authors.lastname: Botella
authors.forename: Sebastian
authors.initials: S
authors.lastname: Hübner
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Devine
mesh_terms: D001412:Bacillus subtilis / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D002473:Cell Wall / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D050296:Microbial Viability; D010457:Peptidoglycan / Q000235:genetics / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism*; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D018085:Regulon
chemical_list: D001426:Bacterial Proteins; D010457:Peptidoglycan; D010710:Phosphates; C119939:YycF protein, Bacteria; C061279:PhoR protein, Bacteria; C061064:PhoP protein, Bacteria; D011494:Protein Kinases