Genome-wide identification of ubiquitin proteasome subunits as superior reference genes for transcript normalization during receptacle development in strawberry cultivars.

BACKGROUND: Gene transcripts that show invariant abundance during development are ideal as reference genes (RGs) for accurate gene expression analyses, such as RNA blot analysis and reverse transcription-quantitative real time PCR (RT-qPCR) analyses. In a genome-wide analysis, we selected three "Commonly used" housekeeping genes (HKGs), fifteen "Traditional" HKGs, and nine novel genes as candidate RGs based on 80 publicly available transcriptome libraries that include data for receptacle development in eight strawberry cultivars. RESULTS: The results of the multifaceted assessment consistently revealed that expression of the novel RGs showed greater stability compared with that of the "Commonly used" and "Traditional" HKGs in transcriptome and RT-qPCR analyses. Notably, the majority of stably expressed genes were associated with the ubiquitin proteasome system. Among these, two 26 s proteasome subunits, RPT6A and RPN5A, showed superior expression stability and abundance, and are recommended as the optimal RGs combination for normalization of gene expression during strawberry receptacle development. CONCLUSION: These findings provide additional useful and reliable RGs as resources for the accurate study of gene expression during receptacle development in strawberry cultivars.