Selection of reference genes for quantitative real-time PCR in Octopus minor (Cephalopoda: Octopoda) under acute ammonia stress

High concentration of ammonia is a common issue in the aquaculture industry and often causes detrimental effects to aquatic products. Exploring expression regulation of genes involved in acute ammonia stress can help to understand the molecular mechanisms of ammonia response. Quantitative real-time PCR (qRT-PCR) with proper reference genes is an effective way to normalize the expression of target genes. To identify the most suitable reference genes for Octopus minor (Mollusca: Cephalopoda: Octopoda) under acute ammonia stress and the normal culturing, nine candidate genes were selected for the validation: OD, RPS18b, RPL29, RPS5, EF-1α, RPL6, AA4, ACT, TUB. The results showed that the stability of candidate genes varied considerably in gill, digestive gland, brain and hemolymph. Thus, the reference genes were determined separately in different tissues. RPS5 and RPL6 showed relatively high stability in gill, while RPL6, TUB, RPL29 and OD were four suitable reference genes in digestive gland. EF-1α, TUB and RPL6 were the best combination in brain and EF-1α and RPS18b were the most appropriate reference genes in hemolymph.