title: Analysis on Actinobacillus pleuropneumoniae LuxS regulated genes reveals pleiotropic roles of LuxS/AI-2 on biofilm formation, adhesion ability and iron metabolism.
abstract: LuxS is an enzyme involved in the activated methyl cycle and the by-product autoinducer-2 (AI-2) was a quorum sensing signal in some species. In our previous study, the functional LuxS in AI-2 production was verified in the porcine respiratory pathogen Actinobacillus pleuropneumoniae. Enhanced biofilm formation and reduced virulence were observed in the luxS mutant. To comprehensively understand the luxS function, in this study, the transcriptional profiles were compared between the A. pleuropneumoniae luxS mutant and its parental strain in four different growth phases using microarray. Many genes associated with infection were differentially expressed. The biofilm formation genes pgaABC in the luxS mutant were up-regulated in early exponential phase, while 9 genes associated with adhesion were down-regulated in late exponential phase. A group of genes involved in iron acquisition and metabolism were regulated in four growth phases. Phenotypic investigations using luxS mutant and both genetic and chemical (AI-2) complementation on these virulence traits were performed. The results demonstrated that the luxS mutant showed enhanced biofilm formation and reduced adhesion ability and these effects were not due to lack of AI-2. But AI-2 could increase biofilm formation and adhesion of A. pleuropneumoniae independent of LuxS. Growth under iron restricted condition could be controlled by LuxS through AI-2 production. These results revealed pleiotropic roles of LuxS and AI-2 on A. pleuropneumoniae virulence traits.
authors.affiliation: Division of Animal Infectious Diseases, State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Shizishan Street 1, Wuhan 430070, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Li
authors.forename: Zhuofei
authors.initials: Z
authors.lastname: Xu
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhou
authors.forename: Tingting
authors.initials: T
authors.lastname: Li
authors.forename: Lili
authors.initials: L
authors.lastname: Sun
authors.forename: Huanchun
authors.initials: H
authors.lastname: Chen
authors.forename: Rui
authors.initials: R
authors.lastname: Zhou
mesh_terms: D016977:Actinobacillus pleuropneumoniae / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D001422:Bacterial Adhesion / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D018441:Biofilms / Q000254:growth & development*; D013437:Carbon-Sulfur Lyases / Q000235:genetics / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial; D006714:Homoserine / Q000031:analogs & derivatives* / Q000235:genetics / Q000502:physiology; D007501:Iron / Q000378:metabolism*; D007783:Lactones; D009154:Mutation; D053038:Quorum Sensing; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D007783:Lactones; C091088:N-octanoylhomoserine lactone; D006714:Homoserine; D007501:Iron; D013437:Carbon-Sulfur Lyases; C117753:LuxS protein, Bacteria