RESUMO
Adaptation and efficient colonization of the phyllosphere are essential processes for the switch to an epiphytic stage in foliar bacterial pathogens. Here, we explore the interplay among light perception and global transcriptomic alterations in epiphytic populations of the hemibiotrophic pathogen Pseudomonas syringae pv. tomato DC3000 (PsPto) following contact with tomato leaves. We found that blue-light perception by PsPto on leaf surfaces is required for optimal colonization. Blue light triggers the activation of metabolic activity and increases the transcript levels of five chemoreceptors through the function of light oxygen voltage and BphP1 photoreceptors. The inactivation of PSPTO_1008 and PSPTO_2526 chemoreceptors causes a reduction in virulence. Our results indicate that during PsPto interaction with tomato plants, light perception, chemotaxis, and virulence are highly interwoven processes.
Assuntos
Proteínas de Bactérias/metabolismo , Fotorreceptores Microbianos/metabolismo , Doenças das Plantas/microbiologia , Pseudomonas syringae/efeitos da radiação , Solanum lycopersicum/microbiologia , Transcriptoma/efeitos da radiação , Proteínas de Bactérias/genética , Quimiotaxia/efeitos da radiação , Regulação Bacteriana da Expressão Gênica/efeitos da radiação , Luz , Fotorreceptores Microbianos/genética , Folhas de Planta/microbiologia , Folhas de Planta/efeitos da radiação , Pseudomonas syringae/genética , Pseudomonas syringae/patogenicidade , Pseudomonas syringae/fisiologia , Virulência/efeitos da radiaçãoRESUMO
Multidrug resistance efflux pumps protect bacterial cells against a wide spectrum of antimicrobial compounds. PSPTO_0820 is a predicted multidrug transporter from the phytopathogenic bacterium Pseudomonas syringae pv. tomato DC3000. Orthologs of this protein are conserved within many Pseudomonas species that interact with plants. To study the potential role of PSPTO_0820 in plant-bacteria interaction, a mutant in this gene was isolated and characterized. In addition, with the aim to find the outer membrane channel for this efflux system, a mutant in PSPTO_4977, a TolC-like gene, was also analyzed. Both mutants were more susceptible to trans-cinnamic and chlorogenic acids and to the flavonoid (+)-catechin, when added to the culture medium. The expression level of both genes increased in the presence of (+)-catechin and, in the case of PSPTO_0820, also in response to trans-cinnamic acid. PSPTO_0820 and PSPTO_4977 mutants were unable to colonize tomato at high population levels. This work evidences the involvement of these two proteins in the resistance to plant antimicrobials, supporting also the importance of chlorogenic acid, trans-cinnamic acid, and (+)-catechin in the tomato plant defense response against P. syringae pv. tomato DC3000 infection.
Assuntos
Subfamília B de Transportador de Cassetes de Ligação de ATP/metabolismo , Proteínas de Bactérias/metabolismo , Doenças das Plantas/microbiologia , Pseudomonas syringae/metabolismo , Pseudomonas syringae/patogenicidade , Solanum lycopersicum/microbiologia , Anti-Infecciosos/metabolismo , Peptídeos Catiônicos Antimicrobianos/metabolismo , Genes Bacterianos , Interações entre Hospedeiro e Microrganismos/genética , Solanum lycopersicum/metabolismo , Mutação , Proteínas de Plantas/metabolismo , Virulência/genéticaRESUMO
We identified the mucus-activatable Shiga toxin genotype stx2d in the most common hemolytic uremic syndrome-associated Escherichia coli serotype, O157:H7. stx2d was detected in a strain isolated from a 2-year-old boy with bloody diarrhea in Spain, and whole-genome sequencing was used to confirm and fully characterize the strain.
