Comparative genomics of pesticide-degrading Enterococcus symbionts of Spodoptera frugiperda (Lepidoptera: Noctuidae) leads to the identification of two new species and the reappraisal of insect-associated Enterococcus species

Enterococcus species have been described as core members of the microbial community of Spodoptera frugiperda (Lepidoptera:Noctuidae) and have been reported in previous studies as insecticide degrading agents. Phenotypic assays and comparative genomics analyses of several pesticide-degrading Enterococcus isolated from the larval gut of S. frugiperda led to the identification of Enterococcus entomosocium n. sp. and Enterococcus spodopteracolus n. sp. Their identities as new species were confirmed by whole genome alignment using the cut-offs of 95-96% for the average nucleotide identity (ANI) and 70% for the digital DNA:DNA hybridization (dDDH) values. The systematic positioning of these new species within the genus Enterococcus was resolved using genome-based analysis, placing Enterococcus casseliflavus as the sister group of E. entomosocium n. sp., and Enterococcus mundtii of E. spodopteracolus n. sp. Comparative genomic analyses of several isolates of E. entomosocium n. sp. and E. spodopteracolus n. sp. led to a better assessment of the interactions established in the symbiotic association with S. frugiperda, and the discovery of misidentified new species of Enterococcus associated with insects. Our analyses also indicated the potential of E. entomosocium n. sp. And E. spodopteracolus n. sp. to metabolize different pesticides arises from molecular mechanisms that result in the rapid evolution of new phenotypes in response to environmental stressors; in this case, the pesticides their host insect is exposed to.