Selection and validation of reference genes for quantitative Real-Time PCR in Arabis alpina.

Arabis alpina is a perennial arctic-alpine plant and an upcoming model organism for genetics and molecular biology for the Brassicaceae family. One essential method for most molecular approaches is the analysis of gene expression by reverse-transcription quantitative Real-Time PCR (RT-qPCR). For the normalisation of expression data in RT-qPCR experiments， it is essential to use reliable reference genes that are not affected under a wide range of conditions. In this study we establish a set of 15 A. alpina reference genes that were tested under different conditions including cold， drought， heat， salt and gibberellic acid treatments. Data analyses with geNORM， BestKeeper and NormFinder revealed the most stable reference genes for the tested conditions: RAN3， HCF and PSB33 are most suitable for cold treatments; UBQ10 and TUA5 for drought; RAN3， PSB33 and EIF4a for heat; CAC， TUA5， ACTIN 2 and PSB33 for salt and PSB33 and TUA5 for gibberellic acid treatments. CAC and ACTIN 2 showed the least variation over all tested samples. In addition， we show that two reference genes are sufficient to normalize RT-qPCR data under our treatment conditions. In future studies， these reference genes can be used for an adequate normalisation and thus help to generate high quality RT-qPCR data in A. alpina.