TITLE:
Analysis of Global DNA Methylation in Irradiated Fig Selections
AUTHORS:
Maria Gabriela Fontanetti Rodrigues, Murilo Racy Soares, Ester Silveira Ramos, Silvana Giuliatti
KEYWORDS:
Epigenetics, Methylation, Mutagenic, Ficus carica
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.6 No.14,
September
4,
2015
ABSTRACT: Fruits from fig tree (Ficus carica L.) are economically important worldwide, and rank among the
top 20 fruits exported by Brazil. However, due to particular features in its floral structure, classical
plant breeding procedures that involve hybridization are not possible. Thus, genetic improvement
of figs by using mutagens is an important line of research. In this study, five fig selections
based on their interesting agronomic features were used. Genetic modifications associated with
mutations were not detected by molecular markers. Therefore, it was suggested that certain phenotypes
could have resulted from epigenetic modifications. The best characterized epigenetic
modification is DNA methylation, which can switch genes on or off by acting as a signal. After epigenetic
polymorphisms were identified by methylation sensitive amplified polymorphism (MSAP)
molecular markers, we quantified the level of DNA methylation in fig selections irradiated with
gamma rays and compared it to levels in the commercial cultivar “Roxo-de-Valinhos.” This was
achieved by analyzing the global methylation using an Imprint Methylated DNA Quantification kit.
The results showed that there were significant differences in global methylation following different
treatments, indicating that irradiation was an abiotic factor that could alter the epigenome of
plants. Since the material used as a control was also found to be methylated, demethylation of the
polymorphic genomic material might account for the phenotypic variations observed among different
treatment groups. These results suggest that irradiation is an external factor that is capable
of altering epigenetic patterns.