Abstract: 【Aim】This study aims to clarify the role of trehalase genes in the resistance to low temperature stress in Calliptamus italicus eggs by cloning trehalase genes in C. italicus eggs, and analyzing their expression profiles in eggs at different developmental stages and the expression changes after cold acclimation. 【Methods】The full-length ORF sequences of trehalase genes from C. italicus eggs were amplified by RT-PCR, and analyzed by bioinformatics tools. RT-qPCR was used to detect the expression changes of trehalase genes in C. italicus eggs at the early stage, diapause stage and diapause termination stage under the room temperature (27℃) and after acclimation to low temperature (0℃) for 15 d. 【Results】Four trehalase genes from C. italicus eggs were cloned and named CiTreM1, CiTreM2, CiTreS1 and CiTreS2, with the GenBank accession numbers of MZ669810, MZ669811, MZ669812 and MZ669813, respectively. Among their encoded proteins, CiTreM1 and CiTreM2 are membrane-bound trehalases, and CiTreS1 and CiTreS2 are soluble trehalases. CiTre genes were expressed in C. italicus eggs at various developmental stages. At the room temperature (27℃), CiTreS1 and CiTreS2 had the highest expression level in C. italicus eggs at the early stage, while CiTreM2 and CiTreM1 had the highest expression level in eggs at the diapause stage and diapause termination stage, respectively. After acclimation to low temperature (0℃) for 15 d， the expression levels of CiTreM1 and CiTreM2 increased in eggs at all the three stages, while those of CiTreS1 and CiTreS2 decreased only in eggs at the early stage but increased in eggs at the other stages. After cold acclimation, the expression levels of CiTreM1 and CiTreM2 increased the most in C. italicus eggs at the early stage, while those of CiTreS1 and CiTreS2 increased the most in eggs at the diapause termination stage. After acclimation to low temperature (0℃) for 15 d, the expression levels of the four CiTre genes were obviously different in C. italicus eggs at the same stage, and CiTreM2 showed the highest expression level in C. italicus eggs at early stage and the diapause stage, and CiTreS1 showed the highest expression level in eggs at the diapause termination stage. 【Conclusion】The four cloned trehalase genes in C. italicus eggs are all involved in the development of C. italicus eggs. According to the changes in expression level before and after cold acclimation, CiTreM2 and CiTreS1 play a key role in the process of C. italicus eggs resisting low temperature stress.

Key words: Calliptamus italicus, embryonic development, trehalase gene, cold acclimation, expression profile