title: Pseudomonas syringae Differentiates into Phenotypically Distinct Subpopulations During Colonization of a Plant Host.
abstract: Bacterial microcolonies with heterogeneous sizes are formed during colonization of Phaseolus vulgaris by Pseudomonas syringae. Heterogeneous expression of structural and regulatory components of the P. syringae type III secretion system (T3SS), essential for colonization of the host apoplast and disease development, is likewise detected within the plant apoplast. T3SS expression is bistable in the homogeneous environment of nutrient-limited T3SS-inducing medium, suggesting that subpopulation formation is not a response to different environmental cues. T3SS bistability is reversible, indicating a non-genetic origin, and the T3SSHIGHand T3SSLOWsubpopulations show differences in virulence. T3SS bistability requires the transcriptional activator HrpL, the double negative regulatory loop established by HrpV and HrpG, and may be enhanced through a positive feedback loop involving HrpA, the main component of the T3SS pilus. To our knowledge, this is the first example of phenotypic heterogeneity in the expression of virulence determinants during colonization of a non-mammalian host.
authors: Depto. Biología Celular, Genética y Fisiología, Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Málaga, E-29071, Spain.
authors: José S
authors: JS
authors: Rufián
authors: Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Seville, 1095, Spain.
authors: María-Antonia
authors: MA
authors: Sánchez-Romero
authors: Depto. Biología Celular, Genética y Fisiología, Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Málaga, E-29071, Spain.
authors: Diego
authors: D
authors: López-Márquez
authors: Depto. Biología Celular, Genética y Fisiología, Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Málaga, E-29071, Spain.
authors: Alberto P
authors: AP
authors: Macho
authors: Faculty of Natural Sciences, Imperial College, London, SW7 2AZ, UK.
authors: John W
authors: JW
authors: Mansfield
authors: Centre for Research in Bioscience, Faculty of Health and Applied Sciences, University of the West of England, Bristol, BS16 1QY, UK.
authors: Dawn L
authors: DL
authors: Arnold
authors: Depto. Biología Celular, Genética y Fisiología, Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Málaga, E-29071, Spain.
authors: Javier
authors: J
authors: Ruiz-Albert
authors: Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Seville, 1095, Spain.
authors: Josep
authors: J
authors: Casadesús
authors: Depto. Biología Celular, Genética y Fisiología, Instituto de Hortofruticultura Subtropical y Mediterránea, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Málaga, E-29071, Spain. cbl@uma.es.
authors: Carmen R
authors: CR
authors: Beuzón
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D010861:Fimbriae, Bacterial / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D027805:Phaseolus / Q000382:microbiology*; D010641:Phenotype; D010935:Plant Diseases / Q000382:microbiology*; D044224:Pseudomonas syringae / Q000235:genetics / Q000254:growth & development* / Q000472:pathogenicity; D013171:Spores, Bacterial / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D014774:Virulence
chemical_list: D001426:Bacterial Proteins