Observatorio de I+D+i UPM

Memorias de investigación
Communications at congresses:
Genetic structure, diversity and selection of the L resistance gene toward Tobamoviruses in Capsicum annuum var. aviculare wild populations in Mexico.
Year:2013
Research Areas
  • Phytopathology,
  • Viral pathogens of plants,
  • Crop production
Information
Abstract
Understanding host-pathogen co-evolution is a central question in Biology as it is at the root of pathogen emergence, host switch and host range expansion, and the composition and dynamics of ecosystems. However, contrary to agroecosystems, evidences for plant-pathogen co-evolution in wild environments are almost non-existent for plant viruses. Thus, we propose to use as a model system the wild pepper Capsicum annuum var. aviculare (chile chiltepin), which is considered as the wild ancestor of the domesticated C. annuum species. Wild populations of chiltepin are found in the tropical dry forests of Mexico (1), where they are exploited for their small pungent fruits, and their cultivation by traditional local farmers has recently started in several regions. A large collection of samples representing wild and cultivated chiltepin populations in Mexico has been obtained (2), and the infecting viruses have been identified. Resistance to tobamoviruses in Capsicum spp. is controlled by alleles at the L locus. The L resistance gene has recently been cloned and characterised (3). This resistance is based on a single-gene locus encoding a CC-NB-LRR protein, which targets the coat protein (CP) of tobamoviruses. This recognition initiates signalling pathways leading to resistance by hypersensitive response (HR). In this study, the L gene frequency was assessed in each chiltepin populations. Interestingly, the frequency of this resistance gene is significantly higher in the wild populations than in the cultivated ones, which suggests that the pre-domestication of this species was not focused on the tobamoviruses resistance. Furthermore, the analysis of more than 100 full-length L gene sequences showed a high variability and a strong geographical structure of this gene. Local adaptations of chiltepin populations toward different tobamovirus pathotypes and/or different environmental conditions could explain the genetic structure of the L gene in Mexico. In addition, several sites under positive selection and co-variations were detected, mainly located in the domain involved in the CP recognition. The roles of these sites on the recognition of viral pathotypes at different environmental conditions will be further investigated. Altogether, these results suggest that the L resistance gene is a target for selection, which could support the hypothesis of co-evolution between chiltepin populations and tobamoviruses in wild ecosystems.
International
Si
Congress
14e Rencontrs de Virologie Végétale
960
Place
Aussois (Francia)
Reviewers
Si
ISBN/ISSN
00-0000-00
Start Date
13/01/2013
End Date
17/01/2013
From page
7
To page
7
Résumés
Participants
  • Autor: Nils Poulicard . (UPM)
  • Autor: Pablo González-Jara (UPM)
  • Autor: Alejandra Moreno-Letelier (Universidad Nacional Autónoma de Mexico)
  • Autor: Aurora Fraile Perez (UPM)
  • Autor: Daniel Piñero (Universidad Nacional Autónoma de Mexico)
  • Autor: Fernando Garcia-Arenal Rodriguez (UPM)
Research Group, Departaments and Institutes related
  • Creador: Grupo de Investigación: Patología Vegetal
  • Centro o Instituto I+D+i: Centro de Biotecnología y Genómica de Plantas, CBGP
  • Departamento: Biotecnología
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