Identification and validation of reference genes for gene expression studies in postharvest rose flower (Rosa hybrida)

- Actin, tublin and ubiquitin expressions were widely investigated in rose flower.
- Reference genes were firstly validated by combining RT-PCR and qRT-PCR in rose.
- Optimal reference genes were identified for postharvest rose flowers.

Optimal reference genes are important for data normalization so that accurate and reliable gene expression measurements may be obtained in both semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) and quantitative real-time RT-PCR (qRT-PCR) methods. This study firstly evaluated potential reference genes in petals of rose flower (Rosa hybrida) under postharvest stress conditions and in various floral organs during flower opening and senescence, combining both RT-PCR and qRT-PCR analysis. The expression stabilities of gene members from three traditional housekeeping gene families - actin (RhACT), tubulin (RhTUB) and ubiquitin (RhUBI) - were assessed using two analysis software packages, geNorm and NormFinder. The results showed that, for cut rose flower, the optimal reference genes were RhUBI1 for dehydration treatment and receptacles; RhTUB2 for exogenous ethylene; RhACT4 for gibberellic and abscisic acid treatments, wounding and stamens; RhUBI6 for petals; RhUBI2 for sepals; and RhACT1 for gynoecia, respectively. Our results provide guidelines for reference gene(s) selection under different postharvest conditions and point the way towards more accurate and widespread use of qRT-PCR in rose flower.