Selection of Suitable Reference Genes for RT-qPCR Normalization under Abiotic Stresses and Hormone Stimulation in Persimmon (Diospyros kaki Thunb)

The success of quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR) to quantify gene expression depends on the stability of the reference genes used for data normalization. To date, systematic screening for reference genes in persimmon (Diospyros kaki Thunb) has never been reported. In this study, 13 candidate reference genes were cloned from 'Nantongxiaofangshi' using information available in the transcriptome database. Their expression stability was assessed by geNorm and NormFinder algorithms under abiotic stress and hormone stimulation. Our results showed that the most suitable reference genes across all samples were UBC and GAPDH, and not the commonly used persimmon reference gene ACT. In addition, UBC combined with RPII or TUA were found to be appropriate for the "abiotic stress" group and α-TUB combined with PP2A were found to be appropriate for the "hormone stimuli" group. For further validation, the transcript level of the DkDREB2C homologue under heat stress was studied with the selected genes (CYP, GAPDH, TUA, UBC, α-TUB, and EF1-α). The results suggested that it is necessary to choose appropriate reference genes according to the test materials or experimental conditions. Our study will be useful for future studies on gene expression in persimmon.