Following the nuclear accidents in the Chernobyl (1986) and Fukushima Dai-Ichi (2011) nuclear power plants, vast areas of land were contaminated with radionuclides, leading to a long-term exposure of the environment to enhanced levels of ionising radiation. In the highest contaminated forests in Chernobyl, located to the west of the Chernobyl reactor, a massive death of Scots pine trees (Pinus sylvestris) was observed shortly after the nuclear accident. Further from the reactor, morphological abnormalities appeared in the pine trees which seem to resemble those found when a plant loses its apical dominance, i.e. growth of the pine trees from two or more emerging branches instead of growing along a primary single trunk. Similar morphological differences were recently found in young Japanese red pine (Pinus densiflora) in the Fukushima Exclusion Zone (FEZ). The mechanisms behind the radiation-induced morphological abnormalities in plants has up to date not been elucidated. However, it is known that cytokinins and auxins play important roles in the division and differentiation of apical meristems. More recently, a strong correlation has been observed between auxin accumulation and DNA methylation.
Therefore, we suggest that radiation leads to a disturbed hormone balance or transport which in turn will lead to morphological changes in P. sylvestris and that epigenetic changes may lie at the basis of the disturbance of the plant hormone balance or transport.
The hypotheses will be investigated by providing answers to the following research question:
1. To what extent do the hormone balances contribute to the changed phenotype observed in P. sylvestris after exposure to ionizing radiation?
2. How does the proteome and the transcriptome of P. sylvestris responds after exposure to ionizing radiation?
3. Do changes in DNA methylation or in the activity of transposable elements contribute to the observed responses in P. sylvestris?
The availability of this topic depends on the outcome of the evaluation of the CHORUS project proposal.