Transcriptome Analysis Revealed the Functions of Lipid Metabolism Under Pieris Japonica Extracts Stress

Spodoptera litura ( S. litura ) is a polyphagous, explosive, and world-distributed agricultural pest. Because of the resistance, resurgence, residue problems of chemical pesticides, new environment-friendly methods are needed to control the spreading of S. litura. The present study was conducted to investigate the effects and mechanisms of a new botanical pesticide, Pieris Japonica extracts (PJE), on S. litura. Methods: PJE was prepared by ethyl acetate and identified by LC-MS/MS. The S. litura were cultivated in our lab. The survival rate, growth and development of S. litura were tested after PJE treatment. RNA-Seq was used to screen the differentially expressed genes (DEGs). GO and KEGG pathway enrichment was conducted to analyze the functions of these DEGs. ELISA was employed to analyze the levels of free fatty acid (FFA), lipase, 3-hydroxyacyl-CoA dehydrogenase (HOAD), and Acetyl-CoA carboxylase (ACC). Hematoxylin and Eosin (H&E) staining were used to detect the development of the fat body. Results: PJE treatment remarkably suppressed the survival rate, the growth and development, and the pupation of S. litura . RNA-Seq screened out 285 DEGs after PJE treatment. Among these DEGs, more than 16 genes were related to lipid metabolism. These 285 DEGs were enriched in terms of cuticle development, worm longevity, fat digestion and absorption. PJE treatment inhibited the levels of FFA, lipase, and HOAD in the hemolymph of S.litura . Conclusion: The present studies revealed that PJE inhibited the growth and development of S. litura via interfering with lipid synthesis, lipolysis, and fat body development.