Identification of reference genes for tissue-specific gene expression in Panax notoginseng using quantitative real-time PCR.

Validated internal controls are prerequisites to accurately normalize gene expression levels. Here, 14 candidate reference genes in Panax notoginseng were characterized. Primer specificity and amplification efficiency were evaluated for each gene. Candidates were subjected to transcript quantification in the root, fibrous root, rhizome, leaf, receptacle, pedicel, and fruit tissues. Expression stability (M value) and normalization factor variation (Vn/Vn+1) were determined by geNorm. 26S-2 and ACT-2 exhibited the highest expression stability among the tissues. Gene expression of dammarenediol synthase was accurately detected after normalization to 26S-2 and ACT-2 was performed. Results were consistent when each or both of 26S-2 and ACT-2 were applied as internal control. Hence, this study provides useful information to normalize gene expression accurately in the tissue-specific transcripts of P. notoginseng.