title: New Multilocus Variable-Number Tandem-Repeat Analysis (MLVA) Scheme for Fine-Scale Monitoring and Microevolution-Related Study of Ralstonia pseudosolanacearum Phylotype I Populations.
abstract: Bacterial wilt caused by theRalstonia solanacearumspecies complex (RSSC) is considered one of the most harmful plant diseases in the world. Special attention should be paid toR. pseudosolanacearumphylotype I due to its large host range, its worldwide distribution, and its high evolutionary potential. So far, the molecular epidemiology and population genetics of this bacterium are poorly understood. Until now, the genetic structure of the RSSC has been analyzed on the worldwide and regional scales. Emerging questions regarding evolutionary forces in RSSC adaptation to hosts now require genetic markers that are able to monitor RSSC field populations. In this study, we aimed to evaluate the multilocus variable-number tandem-repeat analysis (MLVA) approach for its ability to discriminate genetically close phylotype I strains and for population genetics studies. We developed a new MLVA scheme (MLVA-7) allowing us to genotype 580R. pseudosolanacearumphylotype I strains extracted from susceptible and resistant hosts and from different habitats (stem, soil, and rhizosphere). Based on specificity, polymorphism, and the amplification success rate, we selected seven fast-evolving variable-number tandem-repeat (VNTR) markers. The newly developed MLVA-7 scheme showed higher discriminatory power than the previously published MLVA-13 scheme when applied to collections sampled from the same location on different dates and to collections from different locations on very small scales. Our study provides a valuable tool for fine-scale monitoring and microevolution-related study ofR. pseudosolanacearumphylotype I populations.IMPORTANCEUnderstanding the evolutionary dynamics of adaptation of plant pathogens to new hosts or ecological niches has become a key point for the development of innovative disease management strategies, including durable resistance. Whereas the molecular mechanisms underlying virulence or pathogenicity changes have been studied thoroughly, the population genetics of plant pathogen adaptation remains an open, unexplored field, especially for plant-pathogenic bacteria. MLVA has become increasingly popular for epidemiosurveillance and molecular epidemiology studies of plant pathogens. However, this method has been used mostly for genotyping and identification on a regional or global scale. In this study, we developed a new MLVA scheme, targeting phylotype I of the soilborneRalstonia solanacearumspecies complex (RSSC), specifically to address the bacterial population genetics on the field scale. Such a MLVA scheme, based on fast-evolving loci, may be a tool of choice for field experimental evolution and spatial genetics studies.
authors.affiliation: Université de la Réunion, UMR 53 Peuplements Végétaux et Bioagresseurs en Milieu Tropical (PVBMT), Saint Denis, Réunion, France.|CIRAD, UMR 53 Peuplements Végétaux et Bioagresseurs en Milieu Tropical (PVBMT), Pôle de Protection des Plantes, Saint Pierre, Réunion, France.
authors.forename: Jérémy
authors.initials: J
authors.lastname: Guinard
authors.affiliation: CIRAD, UMR 53 Peuplements Végétaux et Bioagresseurs en Milieu Tropical (PVBMT), Pôle de Protection des Plantes, Saint Pierre, Réunion, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Latreille
authors.affiliation: Université de la Réunion, UMR 53 Peuplements Végétaux et Bioagresseurs en Milieu Tropical (PVBMT), Saint Denis, Réunion, France.
authors.forename: Fabien
authors.initials: F
authors.lastname: Guérin
authors.affiliation: Université de la Réunion, UMR 53 Peuplements Végétaux et Bioagresseurs en Milieu Tropical (PVBMT), Saint Denis, Réunion, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Poussier
authors.affiliation: CIRAD, UMR 53 Peuplements Végétaux et Bioagresseurs en Milieu Tropical (PVBMT), Pôle de Protection des Plantes, Saint Pierre, Réunion, France wicker@cirad.fr.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Wicker
mesh_terms: D000220:Adaptation, Biological / Q000235:genetics; D004269:DNA, Bacterial; D062665:Epidemiological Monitoring; D019143:Evolution, Molecular; D005819:Genetic Markers; D014644:Genetic Variation / Q000235:genetics; D005838:Genotype; D018598:Minisatellite Repeats / Q000235:genetics*; D017720:Molecular Epidemiology; D058889:Molecular Typing / Q000379:methods; D005810:Multigene Family; D010802:Phylogeny; D010935:Plant Diseases / Q000382:microbiology; D018547:Plant Stems / Q000382:microbiology; D011110:Polymorphism, Genetic; D043368:Ralstonia solanacearum / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D058441:Rhizosphere; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology; D013045:Species Specificity; D014774:Virulence
chemical_list: D004269:DNA, Bacterial; D005819:Genetic Markers
keywords: VNTR; bacterial wilt; epidemiosurveillance; microevolution; molecular epidemiology; population biology