A major-effect genetic locus, ApRVII, controls resistance against adapted and non-adapted aphid biotypes in pea

International audienceIn a context of reduced insecticide use, the development of cultivars resistant to insect pests is crucial for an integrated pest management. Pea (Pisum sativum) is a crop of major importance among cultivated legumes, for the supply of feed and food proteins and nitrogen in low-input cropping systems. However, yields of the pea crop have become more and more unstable due to rising insect damages with reduced use of pesticides on crops. The pea aphid (Acyrthosiphon pisum) is an insect pest species forming a complex of biotypes, each one adapted to feed on one or a few related legume species. This study aimed to identify resistant genotypes to A. pisum and the underlying genetic determinism by examining a pea collection of 240 genotypes. The collection was screened against a pea-adapted biotype and a non-adapted biotype of A. pisum to characterise their resistance phenotype, through a fecundity test of the aphid installed on the plant in a growth chamber. Partial resistance was observed in some pea genotypes exposed to the pea-adapted biotype. Many pea genotypes were completely resistant to non-adapted biotype, but some exhibited partial susceptibility. A genome association study, using pea exome-capture sequencing data, enabled the identification of a major-effect quantitative trait locus, ApRVII, on chromosome 7. ApRVII includes linkage disequilibrium blocks, which are significantly associated with resistance to one or both of the two pea-adapted and non-adapted aphid biotypes studied. Finally, we identified candidate genes underlying ApRVII that are potentially involved in plant-aphid interactions and marker haplotypes significantly associated with resistance. This study sets the ground for the functional characterization of molecular pathways involved in pea defence to the aphids but also is a step forward for breeding aphid-resistant cultivars