title: Analysis of gene expression in two growth states of Xylella fastidiosa and its relationship with pathogenicity.
abstract: Xylella fastidiosa is a plant pathogen responsible for diseases of economically important crops. Although there is considerable disagreement about its mechanism of pathogenicity, blockage of the vessels is one of the most accepted hypotheses. Loss of virulence by this bacterium was observed after serial passages in axenic culture. To confirm the loss of pathogenicity of X. fastidiosa, the causing agent of citrus variegated chlorosis (CVC), freshly-isolated bacteria (first passage [FP] condition) as well as bacteria obtained after 46 passages in axenic culture (several passage [SP] condition) were inoculated into sweet orange and periwinkle plants. Using real time quantitative polymerase chain reaction, we verified that the colonization of FP cells was more efficient for both hosts. The sequence of the complete X. fastidiosa genome allowed the construction of a DNA microarray that was used to investigate the total changes in gene expression associated with the FP condition. Most genes found to be induced in the FP condition were associated with adhesion and probably with adaptation to the host environment. This report represents the first study of the transcriptome of this pathogen, which has recently gained more importance, since the genome of several strains has been either partially or entirely sequenced.
authors.affiliation: Empresa Brasileira de Pesquisa Agropecuária-EMBRAPA, Cordeirópolis-SP, Brazil.
authors.forename: Alessandra A
authors.initials: AA
authors.lastname: de Souza
authors.forename: Marco A
authors.initials: MA
authors.lastname: Takita
authors.forename: Helvécio D
authors.initials: HD
authors.lastname: Coletta-Filho
authors.forename: Camila
authors.initials: C
authors.lastname: Caldana
authors.forename: Gustavo H
authors.initials: GH
authors.lastname: Goldman
authors.forename: Giane M
authors.initials: GM
authors.lastname: Yanai
authors.forename: Nair H
authors.initials: NH
authors.lastname: Muto
authors.forename: Regina C
authors.initials: RC
authors.lastname: de Oliveira
authors.forename: Luiz R
authors.initials: LR
authors.lastname: Nunes
authors.forename: Marcos A
authors.initials: MA
authors.lastname: Machado
mesh_terms: D001483:Base Sequence; D032084:Citrus sinensis / Q000382:microbiology; D017931:DNA Primers / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D020869:Gene Expression Profiling; D005798:Genes, Bacterial; D020411:Oligonucleotide Array Sequence Analysis; D010935:Plant Diseases / Q000382:microbiology*; D010945:Plants, Edible / Q000382:microbiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D031053:Vinca / Q000382:microbiology; D014774:Virulence / Q000235:genetics; D044167:Xylella / Q000235:genetics* / Q000254:growth & development / Q000472:pathogenicity*
chemical_list: D017931:DNA Primers; D004269:DNA, Bacterial