Transgenerational genetic and epigenetic changes induced by gamma-ray in Fagopyrum species.

BACKGROUND: DNA changes induced by stress may be stable through cell division and passed to subsequent generations. Plant improvement programs require that individuals develop a new heritable trait. The action of mutagens applied in classical mutagenesis is known from their transgenerational inheritance, observed as mutations. DNA methylation is an epigenetic mechanism that generates heritable phenotypic variation by influencing gene expression and modifying DNA accessibility to mutagens. Fagopyrum esculentum (common buckwheat) and F. tataricum (Tartary buckwheat) are essential for food production and valuable for medical purposes. RESULTS: In this study, we aimed to investigate the transgenerational changes in the genome and epigenome of two Fagopyrum species, by analysing 1st and 3rd generations, followed by treatment with gamma rays. The genomic instability, observed as DNA fragmentation, micronuclei, and changes in cell cycle profile, was observed in 1st generation, whereas 3rd generation shows recovery in DNA stability. Gamma-ray stress caused alterations in the pattern and level of DNA methylation in the roots of both analysed generations. The response to gamma rays depends on the species - in 1st generation, a higher increase in DNA methylation level in F. esculentum and only slight changes in F. tataricum were observed. The DNA methylation level in the 3rd generation changed only in F. esculentum. CONCLUSIONS: Gamma ray is a stress factor that affects the pattern and level of DNA methylation in F. esculentum and F. tataricum. Significant differences were observed between control and 3rd generation only in F. esculentum. Differences in DNA methylation following gamma irradiation between the analysed Fagopyrum species may result from various forms of pollination in the analysed species. By using gamma ray-induced mutation, we got a highly stable mutant of F. tataricum, which may result in a self-pollinating trait. Understanding the changes in DNA methylation following mutagenic treatment can be essential in a breeding programme.