title: Xanthomonas campestris diffusible factor is 3-hydroxybenzoic acid and is associated with xanthomonadin biosynthesis, cell viability, antioxidant activity, and systemic invasion.
abstract: Xanthomonas campestris pv. campestris produces a membrane-bound yellow pigment called xanthomonadin. A diffusible factor (DF) has been reported to regulate xanthomonadin biosynthesis. In this study, DF was purified from bacterial culture supernatants using a combination of solvent extraction, flash chromatography, and high-performance liquid chromatography. Mass spectrometry and nuclear magnetic resonance analyses resolved the DF chemical structure as 3-hydroxybenzoic acid (3-HBA), which was further confirmed by synthetic 3-HBA. Significantly, bioassay and in silico analysis suggest that DF production is widely conserved in a range of bacterial species. Analysis of DF derivatives established the hydroxyl group and its position as the key structural features for the role of DF in xanthomonadin biosynthesis. In addition, we showed that DF is also associated with bacterial survival, H2O2 resistance, and systemic invasion. Furthermore, evidence was also presented that DF and diffusible signaling factor have overlapping functions in modulation of bacterial survival, H2O2 resistance, and virulence. Utilization of different mechanisms to modulate similar virulence traits may provide X. campestris pv. campestris with plasticity in response to various environmental cues.
authors.affiliation: Institute of Molecular and Cell Biology, Singapore. yawenhe@sjtu.edu.cn
authors.forename: Ya-Wen
authors.initials: YW
authors.lastname: He
authors.forename: Ji'en
authors.initials: J
authors.lastname: Wu
authors.forename: Lian
authors.initials: L
authors.lastname: Zhou
authors.forename: Fan
authors.initials: F
authors.lastname: Yang
authors.forename: Yong-Qiang
authors.initials: YQ
authors.lastname: He
authors.forename: Bo-Le
authors.initials: BL
authors.lastname: Jiang
authors.forename: Linquan
authors.initials: L
authors.lastname: Bai
authors.forename: Yuquan
authors.initials: Y
authors.lastname: Xu
authors.forename: Zixin
authors.initials: Z
authors.lastname: Deng
authors.forename: Ji-Liang
authors.initials: JL
authors.lastname: Tang
authors.forename: Lian-Hui
authors.initials: LH
authors.lastname: Zhang
mesh_terms: D000840:Anisoles / Q000378:metabolism*; D000975:Antioxidants / Q000378:metabolism / Q000494:pharmacology*; D001937:Brassica / Q000382:microbiology; D006861:Hydrogen Peroxide; D062385:Hydroxybenzoates / Q000378:metabolism*; D009154:Mutation; D010935:Plant Diseases / Q000382:microbiology; D031224:Raphanus / Q000382:microbiology; D050794:STAT1 Transcription Factor; D013997:Time Factors; D016959:Xanthomonas campestris / Q000166:cytology* / Q000235:genetics / Q000378:metabolism*
chemical_list: D000840:Anisoles; D000975:Antioxidants; D062385:Hydroxybenzoates; D050794:STAT1 Transcription Factor; C108932:xanthomonadin I; C032948:3-hydroxybenzoic acid; D006861:Hydrogen Peroxide