Genes de referência para estudos de estresse hídrico em cana-de-açúcar utilizando RT-PCR

Abstract

In gene expression studies, the reference genes are highly important for quantitative gene expression analysis in view of the need of endogenous standard-setting related to changes in gene expression. Aimed at analyzing reference genes associated with drought stress in genotypes of cane sugar, we selected the RB72910 and RB72454 varieties, identified by the Program for Genetic Improvement of Sugarcane with the highest and lowest tolerance to water deficit, respectively. The genotypes were subjected to drought and field capacity. Regarding the physiology, analysis of photosynthetic rate, transpiration rate and stomatal conductance was performed. Observed for the physiological variables, there is a significant difference only between treatments, while the genotypes did not differ statistically. The analysis of variance and geNorme, NormFinder and BestKeeper softwars were used to analyze gene expression, obtained by RT-PCR in eight reference genes, these are: α-Tubulin, β-Tubulin, β-Actin, Cyclophilin, Elogation, GAPDH, Histone and Ubiquitin. Thus, there was significant difference in gene expression between treatments, genes and genotypes. Among the candidate gene, GAPDH was identified with greater stability by software already mentioned. These results indicate that although the genotype exhibited similar physiological behavior, genes reference to tested possessed differential gene expression characteristic that describes the most stable reference genes among all tested genes. Thus, we conclude that, when used without partnership, GAPDH is best suited for projects related to water stress in sugar cane studies reference gene.