Transcriptome analysis of soybean looper, Chrysodeixis includens, provides insight into the potential resistance mechanism to diamide insecticide

Soybean looper (Chrysodeixis includens) is a defoliating pest of soybean and leads to around 16% of total insect damage in crops in Mississippi. They are known for their annual migration behavior between the Central America and the United States. A chemical control of the pest has been successful with diamides, including chlorantraniliprole, over the last decade. Recently, decreased success rates to manage the soybean looper has been detected in the soybean fields in Puerto Rico, leading us to investigate a risk of resistance to diamides. In our previous study, we showed a moderate resistance of the Puerto Rico (PR) strain to chlorantraniliprole. Here we report a comparative transcriptome analysis between the PR and lab strains, where a variety of genes are differentially expressed depending on the resistance status. Some genes encoding cuticle proteins, cytochrome P450s, ABC transporters, and antimicrobial peptides were up-regulated in the PR strain, whereas some genes encoding other metabolic enzymes, odorant receptors, and regulatory components were down-regulated in the PR strain. Dynamic profiles of the transcriptomes will be further discussed more in detail. Currently, the differentially-expressed genes are under investigation by functional analysis.