Genomic features of the polyphagous cotton leafworm Spodoptera littoralis

Abstract

AbstractBackgroundThe cotton leafworm,Spodoptera littoralis, is a highly polyphagous pest of many cultivated plants and crops in Africa and Europe. The genome of this pest will help us to further understand the molecular mechanisms of polyphagy.ResultsHerein, the high-quality genome ofS. littoraliswas obtained by Pacific Bioscience (PacBio) sequencing. The assembled genome size ofS. littoralisis 436.55 Mb with a scaffold N50 of 6.09 Mb, consisting of 17,207 annotated protein-coding genes. Phylogenetic analysis shows thatS. littoralisand its sibling speciesS. lituradiverged about 5.44 million years ago. Expanded gene families were mainly involved in metabolic detoxification and tolerance to toxic xenobiotics based on GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analysis. Comparative genomics analysis showed that gene families involved in detoxification and chemosensation were significantly expanded inS. littoralis, representing genetic characteristics related to polyphagy and an extensive host range.ConclusionsWe assembled and annotated the reference genome ofS. littoralis, and revealed that this pest has the genetic features of strong detoxification capacity, consistent with it being a significant risk to a wide range of host crops. These data resources will provide support for risk assessment and early warning monitoring of major polyphagous agricultural pests.