Selection of reference genes for Harmonia axyridis (Coleoptera: Coccinellidae) feeding on different diets

The selection of a stable reference gene is vital to gene expression studies and to improving the accuracy of RT-qPCR data. With the deep research on the artificial feed of the Harmonia axyridis, there is an increasing need to evaluate the effects of feed on insects at the molecular level. To identify a reference gene to assess the expression of related genes in Harmonia axyridis (Pallas), ensure the reliability of target gene expression analysis using real-time PCR. Especially for H. axyridis were fed Rhopalosiphum padi (L.) or an artificial diet. In this study, the expression profiles of nine candidate reference genes, including 28SrRNA, 18SrRNA, RPS23, EF1, Actin, ATPase, GAPDH, UBI, RPL13 from different H. axyridis tissues (head, thorax, wing, leg, ovary, and fat body) were investigated. The stability of the nine candidate genes was assessed using geNorm, NormFinder, BestKeeper and RefFinder software, and a comprehensive analysis showed that EF1 is a suitable reference gene for eating different diets of different organizations from H. axyridis. 28SrRNA, 18SrRNA, and RPS23 can also be used as reference genes, but Actin, ATPase, RPL13 are not suitable as an internal reference gene.