Strawberry has received much attention due to its nutritional value, unique flavor, and attractive appearance. The availability of the whole genome sequence and multiple transcriptome databases allows the great possibility to explore gene functions, comprehensively. Gene expression profiles of a target gene can provide clues towards the understanding of its biological function. Quantitative real-time PCR (qRT-PCR) is a preferred method for rapid quantification of gene expression. The accuracy of the results obtained by this method requires the reference genes with consistently stable expression to normalize its data. In present study, the expression stability of seven candidate reference genes in diverse sample subsets of different tissues and fruit developmental stages, and plant subjected to light quality and low temperature treatments was evaluated using three statistical algorithms, geNorm, NormFinder, and BestKeeper. Our data indicated that the expression stability of reference genes varied under different experimental conditions. Overall, DBP, HISTH4, ACTIN1 and GAPDH expressed much more stably. PIRUV, ACTIN2 and 18S were not recommended for normalization in given experimental conditions due to low stability. In addition, the relative expression pattern of HY5 (ELONGATED HYPOCOTYL5) was conducted to further confirm the reliability of the reference genes, which demonstrated the correct adoption of reference genes was of great importance in qRT-PCR analysis. Expression stability of reference genes from strawberry varied across selected experimental conditions. Systematic validation of reference genes prior to calculation of target gene expression level should be done to improve the accuracy and consistency of qRT-PCR analysis.

中文翻译：

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在不同实验条件下评估草莓（Fragaria×ananassa）的qRT-PCR标准化的合适参考基因。

草莓由于其营养价值，独特的风味和诱人的外观而备受关注。完整的基因组序列和多个转录组数据库的可用性为全面探索基因功能提供了极大的可能性。靶基因的基因表达谱可以为了解其生物学功能提供线索。实时定量PCR（qRT-PCR）是快速定量基因表达的一种优选方法。通过这种方法获得的结果的准确性要求参考基因具有一致稳定的表达，以使其数据标准化。在本研究中，七个候选参考基因在不同组织和果实发育阶段的不同样本子集中的表达稳定性，使用geNorm，NormFinder和BestKeeper这三种统计算法对经过光质量和低温处理的植物进行了评估。我们的数据表明参考基因的表达稳定性在不同的实验条件下有所不同。总体而言，DBP，HISTH4，ACTIN1和GAPDH的表达要稳定得多。由于稳定性低，不建议在给定的实验条件下将PIRUV，ACTIN2和18S标准化。此外，进行了HY5（ELONGATED HYPOCOTYL5）的相对表达模式，以进一步确认参考基因的可靠性，这表明正确采用参考基因​​在qRT-PCR分析中非常重要。草莓参考基因的表达稳定性在所选实验条件下有所不同。