Genome-wide identification and multi-level analysis of the HSP gene superfamily in Aphidoletes aphidimyza：sHSP gene family expansion and its role in diapause regulation

Background Insect diapause is a critical adaptive strategy for surviving unfavorable environmental conditions. The predatory insect Aphidoletes aphidimyza , widely used in biological pest control, relies on diapause for commercial storage and application. Heat shock proteins (HSPs), particularly small HSPs (sHSPs), are known to play pivotal roles in stress tolerance and protein homeostasis maintenance during diapause. However, the regulatory mechanisms of the HSP gene superfamily, especially the sHSP gene family, in Aphidoletes aphidimyza diapause remain poorly understood. This study aims to comprehensively analyze the HSP gene superfamily in Aphidoletes aphidimyza and elucidate the functional and regulatory roles of sHSPs in diapause. Results Our findings reveal that Aphidoletes aphidimyza has evolved a multi-layered regulatory mechanism through selective expansion of the sHSP gene family. At the transcriptional level, specific transcription factors bind to sHSP gene promoters, enhancing their expression during diapause. Post-transcriptionally, the intronless, single-exon structure of sHSP genes facilitates rapid mRNA maturation, enabling swift protein synthesis. Post-translational modifications, such as phosphorylation, regulate the oligomeric state of sHSP proteins, allowing them to dissociate into functional dimers and protect cellular protein homeostasis under stress. Notably, a unique branch of the sHSP gene family (CladeX) exhibited significant expansion, higher expression during diapause, and elevated evolutionary rates (Ka/Ks), suggesting its critical role in environmental adaptation. Conclusions This study provides a comprehensive analysis of the Aphidoletes aphidimyza HSP gene superfamily, highlighting the pivotal role of the sHSP gene family, particularly CladeX, in diapause regulation. The multi-level regulatory mechanisms—transcriptional, post-transcriptional, and post-translational—enable Aphidoletes aphidimyza to rapidly respond to adverse conditions like low temperature and short photoperiod, ensuring survival during diapause. These insights not only deepen our understanding of insect diapause but also offer potential applications for improving the storage and commercial use of Aphidoletes aphidimyza as a biological control agent.