Molecular cloning and expression patterns of two small heat shock proteins from Chilo suppressalis(Walker)

Small heat shock proteins (sHSPs) are a very complex protein superfamily that increase insect temperature tolerance. In order to deeply understand the function and role of sHSPs in Chilo suppressalis (Walker), this study isolated and identified two CsHSP genes lacking introns from C. suppressalis, Cshsp23.9 and Cshsp27.3. The cDNA full-length of Cshsp23.9 and Cshsp27.3 were 909 and 1 036 bp encoding 220 and 242 amino acids, respectively. Alignment with homologs and phylogenetic analysis indicated Cshsp23.9 and Cshsp27.3 were two new types of Cshsps in C. suppressalis. Real-time quantitative PCR (qPCR) revealed that Cshsp23.9 had the highest relative expression in hindgut compared with other tissues (head, epidermis, foregut, midgut, fat body, Malpighian tubules, and hemocytes), while Cshsp27.3 expressed the highest in fat body content. When exposed to thermal stress from −11 to 43°C for 2 h, two genes showed different expression patterns. Cshsp23.9 did not respond to low temperature, but could be up-regulated by high temperature and the highest expression temperature was at 36°C. Cshsp27.3 could only be induced by mild temperature, with the highest expression at 15 and 30°C. In conclusion, Cshsp23.9 and Cshsp27.3 existed in different tissues/organs of C. suppressalis, and played different important roles in C. suppressalis to resist temperature stress and regulate physiological activities.