The growth of plants under chronic radiation stress in the Chernobyl area may cause changes in the genome of plants. To assess the extent of genetic and epigenetic changes in nuclear DNA, seeds of the annual crop flax (Linum usitatissimum L.) of the Kyivskyi variety, sown 21 years after the accident and grown for six generations in radioactive (RAD) and remediated (REM) fields were analysed. Flaxseed used for sowing first generation, which served as a reference (REF), was also analysed. The AFLP (Amplified Fragment Length Polymorphism) revealed a higher number of specific EcoRI-MseI loci (3.4-fold) in pooled flaxseed samples harvested from the RAD field compared with the REM field, indicating a link between the mutation process in the flax genome and the ongoing adaptation process. MSAP (Methylation-Sensitive Amplified Polymorphism) detecting EcoRI-MspI and EcoRI-HpaII loci in flax nuclear DNA genome showed no significant differences in methylation level, reaching about 33% in each of the groups studied. On the other hand, significant changes in the DNA methylation pattern of flaxseed samples harvested from the RAD field compared with controls were detected. Pairwise FST comparison revealed within both, EcoRI-MspI and transformed methylation-Sensitive data sets more than a 3-fold increase of genetic divergence in the RAD field compared with both controls. These results indicate that the nuclear genome of flax exposed to chronic radiation for six generations has more mutations and uses DNA methylation as one of the adaptation mechanisms for sustainability under adverse conditions.
© 2022 Scandinavian Plant Physiology Society.