Whole genome comparisons reveal panmixia among fall armyworm (Spodoptera frugiperda) from diverse locations

SCHLUM, KATRINA A.; LAMOUR, KURT; DE BORTOLI, CAROLINE PLACIDI; BANERJEE, RAHUL; MEAGHER, ROBERT; PEREIRA, ELISEU; MURUA, MARIA GABRIELA; SWORD, GREGORY A.; TESSNOW, ASHLEY E.; VITERI DILLON, DIEGO; LINARES RAMIREZ, ANGELA M.; AKUTSE, KOMIVI S.; SCHMIDT-JEFFRIS, REBECCA; HUANG, FANGNENG; REISIG, DOMINIC; EMRICH, SCOTT J.; JURAT-FUENTES, JUAN LUIS

BMC GENOMICS

BIOMED CENTRAL LTD

Año: 2021 vol. 22

1471-2164

Background: The fall armyworm (Spodoptera frugiperda (J.E. Smith)) is a highly polyphagous agricultural pest withlong-distance migratory behavior threatening food security worldwide. This pest has a host range of > 80 plantspecies, but two host strains are recognized based on their association with corn (C-strain) or rice and smallergrasses (R-strain). The population genomics of the United States (USA) fall armyworm remains poorly characterizedto date despite its agricultural threat.Results: In this study, the population structure and genetic diversity in 55 S. frugiperda samples from Argentina,Brazil, Kenya, Puerto Rico and USA were surveyed to further our understanding of whole genome nuclear diversity.Comparisons at the genomic level suggest a panmictic S. frugiperda population, with only a minor reduction ingene flow between the two overwintering populations in the continental USA, also corresponding to distinct hoststrains at the mitochondrial level. Two maternal lines were detected from analysis of mitochondrial genomes. Wefound members from the Eastern Hemisphere interspersed within both continental USA overwinteringsubpopulations, suggesting multiple individuals were likely introduced to Africa.Conclusions: Our research is the largest diverse collection of United States S. frugiperda whole genome sequencescharacterized to date, covering eight continental states and a USA territory (Puerto Rico). The genomic resourcespresented provide foundational information to understand gene flow at the whole genome level among S.frugiperda populations. Based on the genomic similarities found between host strains and laboratory vs. fieldsamples, our findings validate the experimental use of laboratory strains and the host strain differentiation based onmitochondria and sex-linked genetic markers extends to minor genome wide differences with some exceptionsshowing mixture between host strains is likely occurring in field populations.