title: Absence of classical heat shock response in the citrus pathogen Xylella fastidiosa.
abstract: The fastidious bacterium Xylella fastidiosa is associated with important crop diseases worldwide. We have recently shown that X. fastidiosa is a peculiar organism having unusually low values of gene codon bias throughout its genome and, unexpectedly, in the group of the most abundant proteins. Here, we hypothesized that the lack of codon usage optimization in X. fastidiosa would incapacitate this organism to undergo quick and massive changes in protein expression as occurs in a classical stress response. Proteomic analysis of the response to heat stress in X. fastidiosa revealed that no changes in protein expression can be detected. Moreover, stress-inducible proteins identified in the closely related citrus pathogen Xanthomonas axonopodis pv citri were found to be constitutively expressed in X. fastidiosa. These proteins have extremely high codon bias values in the X. citri and other well-studied organisms, but low values in X. fastidiosa. Because biased codon usage is well known to correlate to the rate of protein synthesis, we speculate that the peculiar codon bias distribution in X. fastidiosa is related to the absence of a classical stress response, and, probably, alternative strategies for survival of X. fastidiosa under stressfull conditions.
authors.affiliation: Departamento de Bioquímica, Inst. de Biologia, UNICAMP, Campinas, SP, Brazil.
authors.forename: Daniel
authors.initials: D
authors.lastname: Martins-de-Souza
authors.forename: Daniel
authors.initials: D
authors.lastname: Martins
authors.forename: Gustavo
authors.initials: G
authors.lastname: Astua-Monge
authors.forename: Helvécio Della
authors.initials: HD
authors.lastname: Coletta-Filho
authors.forename: Flavia Vischi
authors.initials: FV
authors.lastname: Winck
authors.forename: Paulo Aparecido
authors.initials: PA
authors.lastname: Baldasso
authors.forename: Bruno Menezes
authors.initials: BM
authors.lastname: de Oliveira
authors.forename: Sérgio
authors.initials: S
authors.lastname: Marangoni
authors.forename: Marcos Antônio
authors.initials: MA
authors.lastname: Machado
authors.forename: José Camillo
authors.initials: JC
authors.lastname: Novello
authors.forename: Marcus Bustamante
authors.initials: MB
authors.lastname: Smolka
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D018835:Chaperonin 10 / Q000235:genetics / Q000378:metabolism; D002957:Citrus / Q000382:microbiology*; D015964:Gene Expression Regulation, Bacterial; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D018869:Heat-Shock Response; D010935:Plant Diseases / Q000382:microbiology; D014974:Xanthomonas / Q000472:pathogenicity / Q000502:physiology; D044167:Xylella / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins; D018835:Chaperonin 10; D006360:Heat-Shock Proteins; C113725:HspA protein, bacteria