Rattus Rattus And Rattus Norvegicus Vitamin K 2,3-Epoxide Reductase Single Nucleotide Polymorphisms In Spain

Rodents are considered one of the animal pests with the greatest impact on agricultural production
and public health. Anticoagulant rodenticides (ARs), used as one of the most effective ways to control rodent
populations worldwide. ARs inhibit the vitamin K 2,3-epoxide reductase (VKORC1) enzyme causing animal
death due to internal haemorrhages. Resistances to ARs are mainly associated with mutations or single
nucleotide polymorphisms (SNPs) in the vkorc1 gene. Strategies based on an Integrated Pest Management
(IPM) try to implement an effective reduction in the use of pesticides decreasing the likelihood of the
appearance of pesticide resistance. The information on this subject is scarce in Spain. Pest control operators
in coordination with the National Association of Environmental Sanitation Companies (ANECPLA)
previously identified the sites with low AR efficacy. We designed a kit with the material for the collection of
samples and a questionnaire for location and treatment identification. We received samples of stools and tails
from brown rat (Rattus norvegicus) and black rat (Rattus rattus) collected from 12 Spanish Autonomous
Communities. We sequenced the vkorc1 exon 3 genomic DNA and identified genotypic vkorc1 variations.
The corresponding amino acid changes at the VKORC1 protein depended on the rodent specie.
Computational analysis of binding predictions establish that the brown rat mutation predicted a high
reduction of the binding affinity of chlorophacinone and brodifacoum. Instead, the black rat mutations
slightly reduced bromadiolone AR binding. These results suggest that rodent mutations found in Spanish
populations may be one of the causes of the increased resistance. Pest control management should increase
accuracy by follow resistance evolution for long time monitoring of the genetics of rodent populations.