Observatorio de I+D+i UPM

Memorias de investigación
Communications at congresses:
Analysis of fitness trade-offs limiting host range expansión in pepper-infecting tobamoviruses.
Year:2017
Research Areas
  • Virology
Information
Abstract
The acquisition of new hosts, or host range expansion, will provide a virus with more opportunities for transmission and survival, but may be limited by across-host fitness trade-offs, that is, increasing the fitness in a new host will decrease fitness in the original one. A major cause of across-host trade-offs in viruses is antagonistic pleiotropy. A relevant case of host range expansion is resistance-breaking (RB), in which viruses acquire the capacity to infect otherwise resistant plant genotypes. Under the gene-for-gene (GFG) model of host-pathogen interactions, resistance breaking should be associated to fitness costs in non-resistant hosts. RB-associated costs have been reported for tobamovirus pathotypes that overcome L-gen resistance in pepper (Fraile et al. 2011, 2014). To explore the causes of BR-associated costs, full-length infectious cDNA clones were obtained from two field isolates of Pepper mild mottle virus (PMMoV) that overcome L2 resistance. Then, all reported coat-protein mutations determining RB of alleles L3 and L4 were introduced, and the parental and mutant genotypes was assayed in the susceptible pepper genotypes L+/L+, L1/L1, L2/L2 and L3/L3. Virus accumulation was quantified as a proxy to fitness, and virulence was estimated as the decrease of plant biomass due to infection. Results show that virus fitness depended on the interaction virus genotype (G) x Environment (E), host genotype being the environment, indicating pleiotropic effects of RB mutations. When these effects were quantified, it was found that pleiotropy was antagonistic or positive depending on the specific RB mutation. Similarly, the fitness of the non-RB P0 pathotype isolates depended on the host plant. Last, RB-mutations also affected virulence, but fitness and virulence were not correlated. These results are significant as they show that selection for RB does depend not only on the resistance allele deployed but on the genotype of susceptible hosts. Thus, results stress the complexity of the mechanisms underlying host range expansion in viruses, and the difficulty of predicting the evolution of RB and, hence, of resistance durability. Also, these results are significant in that they will provide the bases for future model analyses of the evolution of resistance breaking under realistic scenarios.
International
Si
Congress
International Exploratory Workshop 2017: Ecological genomics of coevolutionary interactions
960
Place
Zurich, Switzerland
Reviewers
Si
ISBN/ISSN
000-00-0000-000-0
Start Date
08/01/2017
End Date
13/01/2017
From page
1
To page
1
Proceedings
Participants
  • Autor: Sayanta Bera . (UPM)
  • Autor: Aurora Fraile Perez (UPM)
  • 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 - Biología Vegetal
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