Molecular Characterization of Heat-Induced HSP11.0 and Master-Regulator HSF from Cotesia chilonis and Their Consistent Response to Heat Stress

SIMPLE SUMMARY: Small heat shock proteins (sHSPs) are members of the heat shock protein (HSP) family that play an important role in heat stress, and heat shock factors (HSFs) are transcriptional activators that mainly regulate the expression of HSPs. Cotesia chilonis, the major endoparasitoid of Chilo suppressalis, widely distributes in China and other Asian regions. Previous studies have shown that C. chilonis has a certain thermal tolerance. Here, heat-induced HSP11.0 and master-regulator HSF were cloned and characterized from C. chilonis. The transcription patterns of them in response to different temperatures and time course after temperature treatment were analyzed. This study is the first report on the analysis on hsf gene of C. chilonis. The results of expression patterns will provide new insights into thermoregulation of C. chilonis in response to climate change. ABSTRACT: Small heat shock proteins (sHSPs) are members of the heat shock protein (HSP) family that play an important role in temperature stress, and heat shock factors (HSFs) are transcriptional activators that regulate HSP expression. Cotesia chilonis, the major endoparasitoid of Chilo suppressalis, modulates the C. suppressalis population in the field. In this study, we cloned and characterized two genes from C. chilonis: the heat-induced HSP11.0 gene (Cchsp11.0) that consisted of a 306-bp ORF, and the master regulator HSF (Cchsf) containing an 1875-bp ORF. CcHSP11.0 contained a chaperonin cpn10 signature motif that is conserved in other hymenopteran insects. CcHSF is a typical HSF and contains a DNA-binding domain, two hydrophobic heptad repeat domains, and a C-terminal trans-activation domain. Neither Cchsp11.0 or Cchsf contain introns. Real-time quantitative PCR revealed that Cchsp11.0 and Cchsf were highly induced at 36 °C and 6 °C after a 2-h exposure. Overall, the induction of Cchsf was lower than Cchsp11.0 at low temperatures, whereas the opposite was true at high temperatures. In conclusion, both Cchsp11.0 and Cchsf are sensitive to high and low temperature stress, and the expression pattern of the two genes were positively correlated during temperature stress.