Reference gene selection for miRNA and mRNA normalization in potato in response to potato virus Y

This was the first report on evaluating candidate reference genes for quantifying the expression profiles of both coding (e.g., mRNA) and non-coding (e.g., miRNA) genes in potato response to potato virus Y (PVY) inoculation. The reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR) method was employed to quantify the expression profiles of eight selected candidate reference genes; their expression stability was analyzed by four statistical algorithms, i.e., geNorm, BestKeeper, NormFinder and RefFinder. The most stable reference genes were sEF1a, sTUBb and seIF5 with a high stability. The least stable ones were sPP2A, sSUI1 and sGAPDH. The same reference gene allows for normalization of both miRNA and mRNA levels from a single RNA sample using cDNAs synthesized in a single RT reaction, in which a stem-loop primer was used for miRNAs and the oligo (dT) for mRNAs.