title: The luxS gene is involved in AI-2 production, pathogenicity, and some phenotypes in Erwinia amylovora.
abstract: Erwinia amylovora causes fire blight of apple, pear, and other members of the Rosaceae family. The enzyme LuxS catalyzes the last step in the production of autoinducer-2 (AI-2), a molecule implicated with quorum sensing in many bacterial species. It is now well recognized that LuxS also plays a central role in sulfur metabolism and in the activated methyl cycle, which is responsible for the generation of S-adenosyl-L-methionine. A research paper has reported that luxS is not involved with quorum sensing in Er. amylovora, but in our study, Er. amylovora strain NCPPB1665 (Ea1665) produced luxS-dependent extracellular AI-2 activity. Additionally, the maximal AI-2 activity occurred during late-exponential and early-stationary growth phases and diminished during the stationary phase. The luxS mutant of Ea1665 was constructed, and the phenotypes of a defined luxS mutant have been characterized. Inactivation of luxS in Ea1665 impaired motility, extracellular polysaccharide (EPS) production, and tolerance for hydrogen peroxide, and reduced virulence on pear leaves.
authors.affiliation: College of Plant Protection, Key Laboratory of Monitoring and Management of Plant Diseases and Insects, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Gao
authors.forename: Junxian
authors.initials: J
authors.lastname: Song
authors.forename: Baishi
authors.initials: B
authors.lastname: Hu
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Qianqian
authors.initials: Q
authors.lastname: Liu
authors.forename: Fengquan
authors.initials: F
authors.lastname: Liu
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D013437:Carbon-Sulfur Lyases / Q000235:genetics / Q000502:physiology*; D044084:Erwinia amylovora / Q000235:genetics / Q000472:pathogenicity*; D017353:Gene Deletion; D006714:Homoserine / Q000031:analogs & derivatives* / Q000096:biosynthesis; D006861:Hydrogen Peroxide / Q000378:metabolism; D007783:Lactones; D008124:Locomotion; D018515:Plant Leaves / Q000382:microbiology; D031989:Pyrus / Q000382:microbiology; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins; D007783:Lactones; C091088:N-octanoylhomoserine lactone; D037521:Virulence Factors; D006714:Homoserine; D006861:Hydrogen Peroxide; D013437:Carbon-Sulfur Lyases; C117753:LuxS protein, Bacteria