Proteomic analysis of adult Galeruca daurica (Coleoptera: Chrysomelidae) at different stages during summer diapause.

Galeruca daurica is a new pest causing great losses in the Inner Mongolian grasslands of China. The adults enter obligatory diapause during summer. However, the molecular mechanism of summer diapause remains unknown. We used iTRAQ to conduct proteomic analysis of adult G. daurica at the pre-diapause (PD), diapause (D) and post-diapause (TD) stages during summer diapause. A total of 139 and 118 differentially expressed proteins (DEPs) were detected in D/PD and TD/D comparisons, respectively. Besides a large number of DEPs involved in metabolic process, stress response, cytoskeletal reorganization, and phagosome pathway, many new proteins related to diapause were found in this study, such as encapsulation-relating proteins, odorant binding proteins, chemosensory proteins and ribosomal proteins. KEGG analysis revealed that the phagosome pathway was the only common significantly enriched pathway in both D/PD and TD/D. In addition, juvenile hormone regulation and Ca2+ signaling may play an important role in the regulation of summer diapause in G. daurica. Our proteomic analysis provides a new insight into the mechanism of obligatory summer diapause, and lays a foundation for future molecular level studies.