title: Comparative proteomic analysis of Xanthomonas citri ssp. citri periplasmic proteins reveals changes in cellular envelope metabolism during in vitro pathogenicity induction.
abstract: Citrus canker is a plant disease caused by Gram-negative bacteria from the genus Xanthomonas. The most virulent species is Xanthomonas citri ssp. citri (XAC), which attacks a wide range of citrus hosts. Differential proteomic analysis of the periplasm-enriched fraction was performed for XAC cells grown in pathogenicity-inducing (XAM-M) and pathogenicity-non-inducing (nutrient broth) media using two-dimensional electrophoresis combined with liquid chromatography-tandem mass spectrometry. Amongst the 40 proteins identified, transglycosylase was detected in a highly abundant spot in XAC cells grown under inducing condition. Additional up-regulated proteins related to cellular envelope metabolism included glucose-1-phosphate thymidylyltransferase, dTDP-4-dehydrorhamnose-3,5-epimerase and peptidyl-prolyl cis-trans-isomerase. Phosphoglucomutase and superoxide dismutase proteins, known to be involved in pathogenicity in other Xanthomonas species or organisms, were also detected. Western blot and quantitative real-time polymerase chain reaction analyses for transglycosylase and superoxide dismutase confirmed that these proteins were up-regulated under inducing condition, consistent with the proteomic results. Multiple spots for the 60-kDa chaperonin and glyceraldehyde-3-phosphate dehydrogenase were identified, suggesting the presence of post-translational modifications. We propose that substantial alterations in cellular envelope metabolism occur during the XAC infectious process, which are related to several aspects, from defence against reactive oxygen species to exopolysaccharide synthesis. Our results provide new candidates for virulence-related proteins, whose abundance correlates with the induction of pathogenicity and virulence genes, such as hrpD6, hrpG, hrpB7, hpa1 and hrpX. The results present new potential targets against XAC to be investigated in further functional studies.
authors: Laboratório de Bioquímica e Biologia Molecular Aplicada, Departamento de Genética e Evolução, Universidade Federal de São Carlos, UFSCar, São Carlos, SP, 13565-905, Brazil.
authors: Juliana
authors: J
authors: Artier
authors: Laboratório de Bioquímica e Biologia Molecular Aplicada, Departamento de Genética e Evolução, Universidade Federal de São Carlos, UFSCar, São Carlos, SP, 13565-905, Brazil.
authors: Flávia
authors: F
authors: da Silva Zandonadi
authors: Departamento de Tecnologia, Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal, UNESP, Universidade Estadual Paulista, Jaboticabal, SP, 14884-900, Brazil.
authors: Flávia Maria
authors: FM
authors: de Souza Carvalho
authors: LNBio, CNPEM, Laboratório de Espectrometria de Massas, Laboratório Nacional de Biociências, Campinas, SP, 13083-970, Brazil.
authors: Bianca Alves
authors: BA
authors: Pauletti
authors: LNBio, CNPEM, Laboratório de Espectrometria de Massas, Laboratório Nacional de Biociências, Campinas, SP, 13083-970, Brazil.
authors: Adriana Franco Paes
authors: AFP
authors: Leme
authors: Laboratório de Bioquímica e Biologia Molecular Aplicada, Departamento de Genética e Evolução, Universidade Federal de São Carlos, UFSCar, São Carlos, SP, 13565-905, Brazil.
authors: Carolina Moretto
authors: CM
authors: Carnielli
authors: Departamento de Ciências Fisiológicas, Universidade Federal de São Carlos, UFSCar, São Carlos, SP, 13565-905, Brazil.
authors: Heloisa Sobreiro
authors: HS
authors: Selistre-de-Araujo
authors: Departamento de Bioquímica e Tecnologia Química, Instituto de Química, UNESP, Universidade Estadual Paulista, Araraquara, SP, 14800-060, Brazil.
authors: Maria Célia
authors: MC
authors: Bertolini
authors: Departamento de Tecnologia, Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal, UNESP, Universidade Estadual Paulista, Jaboticabal, SP, 14884-900, Brazil.
authors: Jesus Aparecido
authors: JA
authors: Ferro
authors: Departamento de Fitopatologia e Nematologia, Escola Superior de Agricultura 'Luiz de Queiroz', Universidade de São Paulo, Piracicaba, SP, 13418-900, Brazil.
authors: José
authors: J
authors: Belasque Júnior
authors: Laboratório de Interações Microbianas, Departamento de Ciências Biológicas, Universidade Federal de São Paulo, UNIFESP, Diadema, SP, 09913-030, Brazil.
authors: Julio Cezar Franco
authors: JCF
authors: de Oliveira
authors: Laboratório de Bioquímica e Biologia Molecular Aplicada, Departamento de Genética e Evolução, Universidade Federal de São Carlos, UFSCar, São Carlos, SP, 13565-905, Brazil.
authors: Maria Teresa Marques
authors: 0000-0003-0308-6287
authors: MTM
authors: Novo-Mansur
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D008954:Models, Biological; D033903:Periplasmic Proteins / Q000378:metabolism*; D020543:Proteome / Q000378:metabolism; D040901:Proteomics; D014974:Xanthomonas / Q000378:metabolism* / Q000472:pathogenicity*
chemical_list: D001426:Bacterial Proteins; D033903:Periplasmic Proteins; D020543:Proteome
keywords: Xanthomonas citri ssp. citri; cell envelope metabolism; citrus canker; differential proteomics; pathogenicity; periplasmic proteins