Screening of reference genes by qRT-PCR in Chelonus formosanus

Chelonus formosanus is an important parasitic natural enemy of Lepidopteran insects and has great value in the biological control of insect pests. To screen the reference genes in the real-time fluorescence quantitative PCR (qRT-PCR) assay of Chelonus formosanus, six candidate reference genes were selected based on transcriptome data, including GAPDH, ACT, TU, TF, HSP, and RP. The expression stability of these six internal reference genes was determined by qRT-PCR in different tissues (head, chest, abdomen) and at different temperatures (11℃and 41℃), as well as with two insecticides (dinotefuran and chlorantraniliprole). The BestKeeper, GeNorm, NormFinder, Delta, and RefFinder were used to evaluate the expression stability of each gene after treatments. The results show that ACT is the most stable gene in different tissue assays. TU was the most stable reference gene in different insecticide experiments. The GAPDH was the most unstable gene in tissue assays and insecticide treatments. Furthermore, the expression of RP was the most stable under high and low temperature stresses, while the HSP was significantly affected by temperature treatments. Taken together, this study provides a basis for selecting reference genes under different conditions. It is also conducive to obtaining accurate and reliable data in the gene expression experiments of Chelonus formosanus.