title: Pyramiding, alternating or mixing: comparative performances of deployment strategies of nematode resistance genes to promote plant resistance efficiency and durability.
abstract: BACKGROUND
  Resistant cultivars are key elements for pathogen control and pesticide reduction, but their repeated use may lead to the emergence of virulent pathogen populations, able to overcome the resistance. Increased research efforts, mainly based on theoretical studies, explore spatio-temporal deployment strategies of resistance genes in order to maximize their durability. We evaluated experimentally three of these strategies to control root-knot nematodes: cultivar mixtures, alternating and pyramiding resistance genes, under controlled and field conditions over a 3-years period, assessing the efficiency and the durability of resistance in a protected crop rotation system with pepper as summer crop and lettuce as winter crop.
  
  
  RESULTS
  The choice of the resistance gene and the genetic background in which it is introgressed, affected the frequency of resistance breakdown. The pyramiding of two different resistance genes in one genotype suppressed the emergence of virulent isolates. Alternating different resistance genes in rotation was also efficient to decrease virulent populations in fields due to the specificity of the virulence and the trapping effect of resistant plants. Mixing resistant cultivars together appeared as a less efficient strategy to control nematodes.
  
  
  CONCLUSIONS
  This work provides experimental evidence that, in a cropping system with seasonal sequences of vegetable species, pyramiding or alternating resistance genes benefit yields in the long-term by increasing the durability of resistant cultivars and improving the long-term control of a soil-borne pest. To our knowledge, this result is the first one obtained for a plant-nematode interaction, which helps demonstrate the general applicability of such strategies for breeding and sustainable management of resistant cultivars against pathogens.
authors.affiliation: INRA, UMR1355 INRA/UNSA/CNRS, Institut Sophia Agrobiotech, BP167, Sophia Antipolis F-06903, France. caroline.caporalino@sophia.inra.fr.
authors.forename: Caroline
authors.initials: C
authors.lastname: Djian-Caporalino
authors.forename: Alain
authors.initials: A
authors.lastname: Palloix
authors.forename: Ariane
authors.initials: A
authors.lastname: Fazari
authors.forename: Nathalie
authors.initials: N
authors.lastname: Marteu
authors.forename: Arnaud
authors.initials: A
authors.lastname: Barbary
authors.forename: Pierre
authors.initials: P
authors.lastname: Abad
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Sage-Palloix
authors.forename: Thierry
authors.initials: T
authors.lastname: Mateille
authors.forename: Sabine
authors.initials: S
authors.lastname: Risso
authors.forename: Roger
authors.initials: R
authors.lastname: Lanza
authors.forename: Catherine
authors.initials: C
authors.lastname: Taussig
authors.forename: Philippe
authors.initials: P
authors.lastname: Castagnone-Sereno
mesh_terms: D000818:Animals; D002212:Capsicum / Q000235:genetics / Q000469:parasitology; D018545:Lactuca / Q000235:genetics / Q000469:parasitology; D009348:Nematoda / Q000472:pathogenicity*; D010935:Plant Diseases / Q000235:genetics* / Q000469:parasitology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D010940:Plant Proteins