Transcript analysis and expression profiling of three heat shock protein 70 genes in the ectoparasitoid Habrobracon hebetor (Hymenoptera: Braconidae)

Abstract

Heat shock proteins (HSPs) are known as chaperones that help with folding of other proteins when cells are under environmental stresses. The upregulation of HSPs is essential for cold survival during insect diapause. The ectoparasitoid Habrobracon hebetor, a potential biological control agent, can enter reproductive diapause when reared at low temperature and short photoperiod. However, the expression of HSPs during diapause of H. hebetor has not been studied. In this study, we sequenced and characterized the full-length complementary DNAs of three Hsp70 genes (HhHsp70I, HhHsp70II and HhHsp70III) from H. hebetor. Their deduced amino acid sequences showed more than 80% identities to their counterparts from other insect species. However, the multiple sequence alignment among the three deduced amino acid sequences of HhHsp70s showed only 46% identities. A phylogenetic analysis of the three HhHsp70s and all other known Hsp70 sequences from Hymenoptera clustered all the Hsp70s into four groups, and the three HhHsp70s were distributed into three different groups. Real-time quantitative polymerase chain reaction analysis showed that the expression of the three HhHsp70 genes in H. hebetor reared at different conditions was quite different. HhHsp70I showed higher relative expression when H. hebetor were reared at 27.5°C than at two lower temperatures (17.5°C and 20°C) regardless of the photoperiod, whereas HhHsp70II showed higher expression when H. hebetor were reared at 20°C and 10 : 14 L : D than when reared at 17.5°C and either 16 : 8 L : D or 10 : 14 L : D. In contrast, HhHSP70III was expressed at similar levels regardless of the rearing conditions. These results may suggest functional differences among the three HhHsp70 genes in H. hebetor.

Molecular characterization and expression of six heat shock protein genes in relation to development and temperature in Trichogramma chilonis

“…The highly conserved motif among HSP60 sequences may indicate that a similar mechanism of coupling ATP hydrolysis to the substrate-refolding process exists [ 14 , 39 , 42 ]. The two TcHSP70 sequences had three conserved HSP70 family signatures and a non-organellar consensus motif, in accordance with the structures of the HSP70 sequences described in Nilaparvata lugens (Homoptera: Delphacidae), Sitodiplosis mosellana (Diptera: Cecidomyiidae) and Habrobracon hebetor (Hymenoptera: Braconidae) [ 43 – 45 ]. The two TcHSP70 sequences showed high similarity with their homologous sequences from other insects.…”

Selection of reference genes for expression analysis using RT-qPCR in the dissemination system of Heliothis virescens ascovirus 3 h (HvAV-3h)

“…Therefore, we inferred that the parasitoid possession of the virus should barely affect the transcription factors. In most studies of Hymenoptera, 18S or ACT has been commonly employed as the reference gene 40 – 42 . At the same time, none of the studies contributed to a comprehensive selection of internal control genes for Hymenoptera (Braconidae).…”