Identification of internal control genes for gene expression studies in olive mesocarp tissue during fruit ripening

Olive (Olea europaea L.) is one of the most important fruit trees in the Mediterranean zone. For olive gene expression studies, reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) is the most used and chosen technique in addition to the use of appropriate reference genes. So in this context, in our research, we analyzed six different genes of control in order to select the most stable one during olive fruit development. We used ten samples from five periods of fruit maturity of two different olive cultivars “Chemlali Sfax” and “Chétoui” during the year 2016. The profiles of expression of studied genes were assessed in three replicates. To analyze the results, we tried to use two Excel-based software: GeNorm and Bestkeeper. It results that software packages selected Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and Elongation factor-2alpha (EF-2α) as stable gene in Chétoui and across cultivars. GAPDH and ACT1 were found as the steadiest ones in Chemlali Sfax. Our study suggests the use of both GAPDH and EF-2α as two reference genes for the normalizing RT-qPCR data in future researches of olive fruit tissue development.