title: Xanthomonas axonopodis pv. citri enters the VBNC state after copper treatment and retains its virulence.
abstract: The most severe form of citrus canker disease is caused by Xanthomonas axonopodis pv. citri (Xac) and affects all types of important citrus crops, reducing fruit yield and quality. Copper-based products are routinely used as a standard control measure for citrus canker. In this work we demonstrate that copper treatment induces the viable but nonculturable (VBNC) state in Xac but does not prevent the development of symptoms in susceptible plants. Short-term exposures to different concentrations of copper solutions were assayed to determine which treatment resulted in Xac nonculturability. Treatment of 10(6) mL(-1) Xac cells for 10 min in a 135-muM CuSO(4) solution (equivalent to three times the free soluble copper concentration applied in one field treatment) resulted in nonculturability. However, 16% of cells were viable based on 5-cyano-2,3-ditolyl tetrazolium chloride staining and 1% were capable of producing canker lesions after infiltrating grapefruit plants. If induction of the VBNC state in Xac cells were to occur under field conditions, this would have to be taken into consideration for an effective control of canker disease.
authors.affiliation: Departamento de Biología Molecular, Instituto de Investigaciones Biológicas Clemente Estable (IIBCE), Montevideo, Uruguay.
authors.forename: Raquel
authors.initials: R
authors.lastname: del Campo
authors.forename: Paola
authors.initials: P
authors.lastname: Russi
authors.forename: Pamela
authors.initials: P
authors.lastname: Mara
authors.forename: Héctor
authors.initials: H
authors.lastname: Mara
authors.forename: Mercedes
authors.initials: M
authors.lastname: Peyrou
authors.forename: Inés Ponce
authors.initials: IP
authors.lastname: de León
authors.forename: Carina
authors.initials: C
authors.lastname: Gaggero
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D032083:Citrus paradisi / Q000382:microbiology; D019327:Copper Sulfate / Q000494:pharmacology*; D050296:Microbial Viability / Q000187:drug effects*; D010935:Plant Diseases / Q000382:microbiology; D014774:Virulence / Q000187:drug effects; D053532:Xanthomonas axonopodis / Q000187:drug effects* / Q000472:pathogenicity*
chemical_list: D000900:Anti-Bacterial Agents; D019327:Copper Sulfate