title: The Type II Secreted Lipase/Esterase LesA is a Key Virulence Factor Required for Xylella fastidiosa Pathogenesis in Grapevines.
abstract: Pierce's disease (PD) of grapevines is caused by Xylella fastidiosa (Xf), a xylem-limited gamma-proteobacterium that is responsible for several economically important crop diseases. The occlusion of xylem elements and interference with water transport by Xf and its associated biofilm have been posited as the main cause of PD symptom development; however, Xf virulence mechanisms have not been described. Analysis of the Xf secretome revealed a putative lipase/esterase (LesA) that was abundantly secreted in bacterial culture supernatant and was characterized as a protein ortholog of the cell wall-degrading enzyme LipA of Xanthomonas strains. LesA was secreted by Xf and associated with a biofilm filamentous network. Additional proteomic analysis revealed its abundant presence in outer membrane vesicles (OMVs). Accumulation of LesA in leaf regions associated positively with PD symptoms and inversely with bacterial titer. The lipase/esterase also elicited a hypersensitive response in grapevine. Xf lesA mutants were significantly deficient for virulence when mechanically inoculated into grapevines. We propose that Xf pathogenesis is caused by LesA secretion mediated by OMV cargos and that its release and accumulation in leaf margins leads to early stages of observed PD symptoms.
authors.affiliation: Plant Sciences Department, University of California, Davis, 1 Shields Ave, Davis CA, 95616, USA.|Institute of Genetics and Biochemistry, Federal University of Uberlândia, Av. Amazonas, Bloco 2E, Campus Umuarama, 38400-902, Uberlândia MG, Brazil.
authors.forename: Rafael
authors.initials: R
authors.lastname: Nascimento
authors.affiliation: Plant Sciences Department, University of California, Davis, 1 Shields Ave, Davis CA, 95616, USA.
authors.forename: Hossein
authors.initials: H
authors.lastname: Gouran
authors.affiliation: Plant Sciences Department, University of California, Davis, 1 Shields Ave, Davis CA, 95616, USA.
authors.forename: Sandeep
authors.initials: S
authors.lastname: Chakraborty
authors.affiliation: Plant Sciences Department, University of California, Davis, 1 Shields Ave, Davis CA, 95616, USA.
authors.forename: Hyrum W
authors.initials: HW
authors.lastname: Gillespie
authors.affiliation: Institute of Genetics and Biochemistry, Federal University of Uberlândia, Av. Amazonas, Bloco 2E, Campus Umuarama, 38400-902, Uberlândia MG, Brazil.
authors.forename: Hebréia O
authors.initials: HO
authors.lastname: Almeida-Souza
authors.affiliation: Plant Sciences Department, University of California, Davis, 1 Shields Ave, Davis CA, 95616, USA.
authors.forename: Aye
authors.initials: A
authors.lastname: Tu
authors.affiliation: Department of Biological Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India.
authors.forename: Basuthkar J
authors.initials: BJ
authors.lastname: Rao
authors.affiliation: Plant Pathology Department, University of California, Davis, 1 Shields Ave, Davis CA, 95616, USA.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Feldstein
authors.affiliation: Plant Pathology Department, University of California, Davis, 1 Shields Ave, Davis CA, 95616, USA.
authors.forename: George
authors.initials: G
authors.lastname: Bruening
authors.affiliation: Medical Microbiology and Immunology Department, University of California, Davis, 1 Shields Ave, Davis CA, 95616, USA.|Institute of Genetics and Biochemistry, Federal University of Uberlândia, Av. Amazonas, Bloco 2E, Campus Umuarama, 38400-902, Uberlândia MG, Brazil.
authors.forename: Luiz R
authors.initials: LR
authors.lastname: Goulart
authors.affiliation: Plant Sciences Department, University of California, Davis, 1 Shields Ave, Davis CA, 95616, USA.
authors.forename: Abhaya M
authors.initials: AM
authors.lastname: Dandekar
mesh_terms: D004950:Esterases / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D008049:Lipase / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D010641:Phenotype; D010935:Plant Diseases / Q000382:microbiology; D018515:Plant Leaves / Q000382:microbiology / Q000502:physiology; D021381:Protein Transport; D040901:Proteomics / Q000379:methods; D053038:Quorum Sensing / Q000235:genetics; D022142:Secretory Vesicles / Q000378:metabolism / Q000648:ultrastructure; D000069178:Type II Secretion Systems; D014774:Virulence / Q000235:genetics; D037521:Virulence Factors / Q000378:metabolism; D027843:Vitis / Q000382:microbiology*; D044167:Xylella / Q000472:pathogenicity / Q000502:physiology* / Q000648:ultrastructure
chemical_list: D000069178:Type II Secretion Systems; D037521:Virulence Factors; D004950:Esterases; D008049:Lipase