Stable reference genes for studies of gene expression in prunus pérsica under water stress

Abstract

Strategies which allow the unequivocal identification of genes expressed in response to different treatments and/or stress conditions are important to obtain reliable results in plant physiology studies. However, in order to analyze the expression levels of target genes through RT-qPCR technique, it is essential to use model genes with uniform expression levels under specific experimental conditions. The present study aimed at investigating the stability of reference genes in peach leaves cultivar scion Chimarrita grafted onto 'Aldrighi 1' and 'Tsukuba 2' rootstock, subjected to water deficit for a 9-day period. The experiment was conducted in a completely randomized design with four treatments that correspond the evaluations period: zero (control), 4th, 7th, and 9th stress day of water deficit. For each treatment three biological replicates was used. Eight reference genes were analyzed, among them: ACT, CYP2, Ef-1a, GAPDH, TUA, TUB, UBQ10 and 18SrRNA. For the normalization and validation of RT-qPCR data were used the four major software programs currently available: geNorm, NormFinder, BestKeeper, and Comparative ACT. The results showed that there was no influence of different plant grafting combinations in the expression of all reference genes evaluated, yet genes TUA and CYP2 had the most stable expression in the leaves of the peach plants under water deficit for 9-d, whereas genes Ef-1a and ACT were the least stable ones for the same stress conditions.