Reference genes assessment for the seagrass Posidonia oceanica in different salinity, pH and light conditions

The stability on the expression level of putative reference genes (RGs) for reverse transcriptase-quantitative PCR (RT-qPCR) was tested in the seagrass Posidonia oceanica for plants collected in different environmental conditions (at different depths and in different salinity and pH). Besides adult plants, seedlings were also used for pH and salinity experiments. The putative RGs encompassed the most frequently used in other species to normalize RT-qPCR in a range of experimental conditions. Assignment of the best RGs has been performed with three Excel-based applets, BestKeeper, geNorm and NormFinder, and the results showed that best RGs may change depending on the experimental conditions tested, plant age and on the software utilized. Preferred sets of RGs are proposed for each of the conditions and a general procedure concerning their selection is discussed. In addition, expression levels of four genes involved in plant response to light, salinity and pH variation have also been evaluated.