Selection and validation of reference genes for normalization of qRT-PCR gene expression in wheat ( L.) under drought and salt stresses.

Eight candidate housekeeping genes were examined as internal controls for normalizing expression analysis of durum wheat () under drought and salinity stress conditions. Quantitative real-time PCR was used to analyse gene expression of multiple stress levels, plant ages (24 and 50 days old), and plant tissues (leaf and root). The algorithms BestKeeper, NormFinder, GeNorm, the delta Ct method and the RefFinder were applied to determine the stability of candidate genes. Under drought stress, the most stable reference genes were , and β-, whereas under salinity stress conditions, , and were identified as the most stable reference genes. Validation with stress-responsive genes and demonstrated that the expression level of target genes could be determined reliably with combinations of up to three of the reference genes. This is the first report on reference genes appropriate for quantification of target gene expression in under drought and salt stresses. Results of this investigation may be applicable to other species.