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Disentangling consanguinity and Wahlund effect in cyst plant parasitic nematodes

Disentangling consanguinity and Wahlund effect in cyst plant parasitic nematodes


Context and Issues

Previous works have highlighted strong heterozygote deficits (FIS >> 0) in natural populations of Globodera pallida and Heterodera shachtii which attack potato and sugar beet, respectively. However, it has never been determined whether the observed deficits were due

  • to the presence of null alleles in data sets
  • to an high level of consanguinity and/or
  • to a genetic structuration at a sub-population scale (Wahlund effect).


The goal of the project is to identify through experimentations and development of new sets of molecular markers which of these hypotheses can explain those heterozygote deficits. This research question is also important in terms of transfer to agro-ecosystems, and in particular for the management of plant resistances. While consanguineous mating leads to homozygosity at all loci including loci governing avirulence/virulence, heterozygote deficits due to the Wahlund effect are expected to have no particular effect on the adaptation of nematodes to resistance genes.

Main Results

Results produced here will potentially open new research areas to investigate, as for instance the soil tillage effect, in order to improve the durability of cyst nematode resistance genes. Moreover, the comparison between populations from landscapes strongly and lightly human-driven (wild and cultivated compartments) will allow us to test the effect of agriculture on the explicative part of both phenomena (cansanguinity versus Wahlund effect).