Short communicationIdentification of appropriate reference genes for RT-qPCR analysis in Ziziphus jujuba Mill.

•This is the first report regarding the selection of appropriate reference genes for RT-qPCR analysis in jujube (Ziziphus jujuba Mill.).•The most stable set of reference genes were screened for fruit developmental stages, tissues and genotypes of jujube.•None of the reference genes were consistently expressed across all experimental samples evaluated.

Reverse transcription quantitative real-time PCR (RT-qPCR) is the most widely used method to evaluate the expression levels of mRNA, and the stability of reference genes is crucial for correct evaluation of RT-qPCR data. In the present work, 11 candidate reference genes were investigated for their expression levels at six fruit developmental stages and among four tissues and five genotypes of Ziziphus jujuba Mill. The geNorm, Normfinder and Bestkeeper software programs were applied to estimate the stability of the 11 reference genes. The results showed that UBQ, ACTIN, CYP and ACTIN9 for the fruit developmental stages, UBQ2 and UBQ for the different tissues, UBQ2, GAPDH, ACTIN9 and EF1 for the different genotypes, and UBQ, ACTIN9, UBQ2 and CYP for all samples evaluated were stably expressed. Additionally, the relative GME expression level was used to validate the reference genes. The findings may enable more accurate assessments of gene expression in Z. jujuba Mill.