Selection of stable reference genes for gene expression analysis in sweet potato (Ipomoea batatas L.)

Gene expression analysis is one of the most common and important studies in biology and biomedicine. No matter for traditional blotting analysis or currently commonly used PCR strategy, all need a stable reference gene for normalizing the gene expression. To screen and select housekeeping genes as the most stable reference genes, quantitative real-time PCR (qRT-PCR) was employed to analyze the expression of sixteen commonly used reference genes (IbelF, Ibα-tubulin, IbHIS, IbCOX, IbGAPDH, IbH2B1, IbARF, IbCYC, Ibβ-tubulin, IbACT, IbEFl-a, IbG14, IbPLD, IbRPL2, IbUBQ, IbUBI) in five different tissues under two different temperature stresses in sweet potato. Data analysis by the Delta CT, geNorm, NormFinder, and BestKeeper programs revealed that IbelF is the most stable gene and IbUBI is the least stable gene as reference. Our study also shows that combination of two or more genes as reference is a better choice, rendering more substantiated expression data for comparison. This study provides evidence for selecting reference genes in sweet potato gene expression analysis.