Development and selection of stably expressed reference genes for expression normalization in Ribes odoratum under drought stress

The stability of internal reference genes is of great significance for the study of gene functions, and the development and screening of stable internal reference genes is the key to gene function analysis. Real-time reverse transcription quantitative PCR (qPCR) is an important tool to measure gene expression levels. Selection of stable reference genes for data normalization is a prerequisite. To date, the lack of studies on validation of reference genes in Ribes odoratum limits application of qPCR in Ribes odoratum. In this study, Through drought stress treatments and transcriptome analysis of Ribes odoratum, this study identified multiple genes with stable expression under drought stress. The expression stability of 17 candidate reference genes under drought stress was evaluated using the Genorm, NormFinder, BestKeeper, and Delta Ct algorithms. The results showed that Cluster-37.22228, Cluster-37.22646 and Cluster-37.22897 were the top three stable reference genes, and the best reference genes that could be used as internal controls in Ribes odoratum was Cluster-37.22228 and Cluster-37.22646. These results provided for the first time a comprehensive list of stable reference genes for the normalization of qPCR analyses in Ribes odoratum under drought stress and will benefit the in-depth molecular biology research in the future.