Abstract:

【Aim】 This study aims to explore the crucial genes and metabolic pathways involved in obligatory summer diapause in Galeruca daurica, a new pest with great outbreak in the Inner Mongolia grasslands, northern China. 【Methods】 Using RNA-Seq, we performed sequencing, transcriptional profiling and functional prediction for G. daurica adults at different summer diapause stages, i.e. pre-diapause (PD), diapause (D) and post-iapause (TD), and screened differentially expressed genes (DEGs) at different summer diapause stages based on the RNA-Seq data. The expression levels of ten DEGs screened based on the RNA-Seq data were verified by qPCR. 【Results】 A total of 202 770 198 clean reads from nine libraries were filtered, and 12 078 060 transcripts were assembled into 82 292 unigenes with an average length of 783.59 bp and a N50 of 1 545 bp. The 2 395 (2 119 up-regulated and 277 down-regulated) and 62 (59 up-regulated and 3 down-regulated) DEGs were identified in the D vs PD and TD vs D omparison groups, respectively. The KEGG analysis revealed that the glycolysis/gluconeogenesis and fatty acid biosynthesis pathways were significantly enriched in the D vs PD and TD vs D comparison groups, respectively. Additionally, many DEGs related to the Ca²⁺ signaling were differentially expressed during diapause. Finally, the expressional analysis result by qPCR for ten DEGs showed a high consistency between qPCR and RNA-Seq results. 【Conclusion】 The glycolysis/gluconeogenesis, fatty acid biosynthesis, and Ca²⁺signaling pathways may play an important role in diapause regulation of G. daurica. This study establishes a foundation for future studies on the molecular mechanism underlying obligatory summer diapause in G. daurica.

Key words: Galeruca daurica, summer diapause, obligatory diapause, RNA-Seq