Effect of chronic radiation on the flax (Linum usitatissimum L.) genome grown for six consecutive generations in the radioactive Chernobyl area

Abstract

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.

Epigenetics for crop adaptation to climate change

“…To counter such losses, Hidvégi et al (2022) explored the effects of ultrasonication on wheat seeds to assess its potential value as a priming technique promoting seedling growth and Two articles in the special issue address the chronic contamination of soil by cadmium (Cd), one focused on flax growing in the Chernobyl area (Jopčík et al, 2022) and the other on "phytomining" approaches to extract Cd from contaminated soils (Karalija et al, 2022). Jopčík et al (2022) analyzed the genomes and epigenomes of sixth consecutive generations of flax plants growing in the radioactive Chernobyl area to measure the extent of their changes and whether they have led to plant adaptation nearly three decades after the Chernobyl nuclear power plant accident. Through proteomic analysis, they detected very limited effects of ionizing radiation on the seed proteome but modification of several enzymes involved in antioxidant defenses.…”

“…The contributions of three epigenetic mechanisms (DNA methylation, histone post‐translational modifications, and enzymatic regulation) are also described and discussed. The reported studies aimed to describe how plants acclimate to abiotic environmental constraints (Alves et al, 2022), including low temperature and drought in early stages of winter wheat seedling establishment (Hidvégi et al, 2022), frost risks in budbreak and flowering stages of apple crops (Lempe et al, 2022), chronic heavy metal contamination in hyperaccumulating plants (Karalija et al, 2022) or flax (Jopčík et al, 2022) in the radioactive Chernobyl area, and biotic stresses such as powdery mildew caused by Plasmopara viticola in grapevine (Azevedo et al, 2022). Most also discussed the contributions of epigenetic regulations in acclimation processes or their evolution under continuous climate change generally, and/or in specific taxa, such as members of the Fagaceae family (Alves et al, 2022).…”

“…Overall, future directions have been proposed and discussed that indicate groundbreaking approaches that could promote the following: tolerance of powdery mildew caused by the biotrophic oomycete Plasmopara viticola in grapevine (Azevedo et al, 2022); acclimation to stressful conditions during sowing and seedling establishment in wheat (Hidvégi et al, 2022); phenological adjustment of budbreak and flowering in apple (Lempe et al, 2022); and adaptation to both chronic heavy metal contaminations (Jopčík et al, 2022; Karalija et al, 2022) and continuous climate change (Alves et al, 2022).…”

“…Two articles in the special issue address the chronic contamination of soil by cadmium (Cd), one focused on flax growing in the Chernobyl area (Jopčík et al, 2022) and the other on “phytomining” approaches to extract Cd from contaminated soils (Karalija et al, 2022). Jopčík et al (2022) analyzed the genomes and epigenomes of sixth consecutive generations of flax plants growing in the radioactive Chernobyl area to measure the extent of their changes and whether they have led to plant adaptation nearly three decades after the Chernobyl nuclear power plant accident. Through proteomic analysis, they detected very limited effects of ionizing radiation on the seed proteome but modification of several enzymes involved in antioxidant defenses.…”