Spodoptera frugiperda Genotyping by sequencing. Spodoptera frugiperda

Here we applied the ddRAD genotyping-by-sequencing technique to investigate the genetic distinctiveness of Brazilian populations of the moth Spodoptera frugiperda, the fall armyworm (FAW), and the role of host plant association as source of genetic diversification. We found that populations sampled from corn are composed primarily of corn strain individuals, while the population sampled from rice is comprised almost entirely by rice strain individuals. Outlier analyzes indicated 1184 putatively under selection loci (ca. 15% of total) related to 194 different Gene Ontologies (GOs); the most represented GOs were nucleotide binding, ATP binding, metal ion binding and nucleic acid binding. The association analyzes indicated 326 loci associated to the host plant, and 216 loci associated to the individual strain, including functions related to Bacillus thuringiensis and insecticide resistance. The genetic structure analyzes indicate a moderate level of differentiation among all populations, and lower genetic structure among populations sampled exclusively from corn, which suggests that the population sampled from rice has a strong influence in the overall genetic structure. Populations of S. frugiperda are structured partially due to the host plant, and pairs of populations using the same host plant are more genetically similar than pairs using different hosts. Under selection loci are the main responsible for the genetic structure of these populations, which is indicative that adaptive selection on important traits are acting in the genetic differentiation of FAW populations in Brazil.