Stability comparison of three candidate internal reference genes in Chinese giant salamander ( Andrias davidianus )

The Chinese giant salamander (Andrias davidianus) as food and medicinal product has been an important aquaculture object in China. Study of gene function in the Chinese giant salamander requires accurate normalization though the use of appropriate reference genes. In this study, the expression levels of three candidate reference genes including β-actin, GAPDH and cytb of different tissues, different developmental stages and different challenges in Chinese giant salamander were evaluated by qPCR. The stabilities of these three reference genes were analysed by geNorm, NormFinder and BestKeeper software. The results showed that the expression of GAPDH was more stable than that of β-actin and cytb in four tissues and at two developmental stages of Chinese giant salamander. Compared with GAPDH and cytb, β-actin was the most stable in spleen of Chinese giant salamander treated with LPS or GSIV. Therefore, the result showed that GAPDH was the suitable reference gene in different tissues and at different developmental stages of Chinese giant salamander. The β-actin could be used as a reference gene in spleen of Chinese giant salamander challenged with LPS and GSIV. This study provides convincing information for the GAPDH and β-actin as suitable reference gene in Chinese giant salamander of different tissues, different developmental stages and different challenges respectively.