Molecular cloning and expression under cold stress of two heat shock proteins from Dastarcus helophoroides (Fairmaire) (Coleoptera: Bothrideridae).

Abstract

Heat shock proteins (HSPs) maintain cellular homeostasis and regulate immune responses across species. HSP90 stabilises and activates regulatory proteins, while HSP70 facilitates protein folding and prevents aggregation. In this study, the complete cDNA sequences of Dastarcus helophoroides - HSP70, HSP90, and β-actin (used as a reference for real-time quantitative polymerase chain reaction) - were obtained using rapid amplification of cDNA ends-polymerase chain reaction, and the expression of HSP70 and HSP90 under cold stress was analysed. The full-length cDNA of HSP90 contains a 2346-bp open reading frame (ORF) encoding 781 amino acids with a molecular weight (MW) of 89.6 kDa. The HSP70 cDNA contains a 1911-bp ORF encoding 636 amino acids (MW: 69.7 kDa), and the β-actin cDNA contains a 1131-bp ORF encoding 376 amino acids (MW: 41.7 kDa). Cold stress significantly affected HSP expression: HSP90 expression peaked at -15 °C, with a 9.45-fold increase compared to the control (P < 0.05), whereas HSP70 expression increased markedly at -10 °C, with a 60.42-fold increase compared to the control (P < 0.05). These findings have important biological implications for predicting insect performance under fluctuating thermal environments and for optimising low-temperature storage and release strategies of D. helophoroides in biological control programmes.