Omics Analysis\nof Odorant-Binding Proteins and Cuticle-Enriched <i>SfruOBP18</i> Confers Multi-Insecticide Tolerance in Spodoptera\nfrugiperda

Spodoptera frugiperda is\na notorious\npest that develops a high resistance to many insecticides. Recently,\ninsect odorant-binding proteins (OBPs) have been proven to participate\nin insecticide resistance. However, the functional evidence supporting\nthe cross-link between OBPs and insecticide resistance remains unexplored.\nHere, we identified 50 SfruOBPs from the larval transcriptome and\ngenome. Notably, <i>SfruOBP18</i> was highly expressed in\nthe larval cuticle and could be induced to upregulate its expression\nby multi-insecticides. Ligand-binding assays revealed that <i>SfruOBP18</i> bound strongly with four insecticides; RNAi and\ninsecticide bioassay demonstrated that the knockdown of <i>SfruOBP18</i> did not affect larval survival and development. However, it can\nsignificantly increase the larval susceptibility to multi-insecticides,\nsuggesting an uncommon role of <i>SfruOBP18</i> in multi-insecticide\nsusceptibility. Our study provides a comprehensive understanding of\nSfruOBPs and furthermore proves that a larval cuticle-enriched OBP\ncan bind with and confer larval tolerance to multi-insecticides. <i>SfruOBP18</i> could be a new insecticidal target for controlling\nLepidoptera pests.