The fertility recovering from heat stress and interactions of heat shock protein 20 with reproduction-related proteins in Monochamus alternatus.

Due to the rise in global temperatures with climate change, insects, as ectotherms, critically depend on their heat tolerance for survival and reproduction. Heat shock proteins (HSPs) are essential for heat tolerance by averting protein denaturation; however, whether HSPs contribute to reproduction-related heat tolerance remains largely unexplored. The study investigated the reproductive heat tolerance and recovery of Monochamus alternatus, a major forestry pest, in response to heat stress. Alongside impairing the development and viability of reproductive organs and sperm, heat stress was also found to reduce fecundity, fertility, mating, and oviposition behaviors. Remarkably, all reproductive parameters of M. alternatus recovered within 4 weeks postexposure. To investigate the recovery mechanisms, we identified 10 reproduction-related proteins as candidate substrate proteins of an HSP protein in M. alternatus using immunoprecipitation coupled with mass spectrometry analysis. Heat stress inhibited the transcription of these reproduction-related genes, thereby adversely affecting reproductive parameters. However, the induction of HSP20s transcription in response to heat stress appeared to facilitate the refolding of these critical reproduction-related proteins during the recovery phase, thus preventing lasting reproductive damage. Overall, this study suggests that while M. alternatus populations might be vulnerable to climate-induced temperature increases, their fertility can recover, mediated by the interaction of HSPs with reproduction-related genes. These findings offer profound insights into insect heat tolerance and recovery, expanding our understanding of HSP20 proteins' biological functions.