Chronic low dose 90Sr contamination in Lemna minor: from transcriptional dynamics of epigenetic regulators to population level effects

TL;DR

This study explores how the plant Lemna minor responds to long-term low-dose radiation, revealing acclimation phases and potential epigenetic mechanisms.

Contribution

The study identifies temporal acclimation phases and links epigenetic regulation to chronic radiation stress in Lemna minor.

Findings

Lemna minor shows morphological and molecular changes in response to chronic 90Sr exposure.

Epigenetic regulators like DNA methylation genes are transcriptionally modulated during acclimation.

The plant exhibits stable yet fluctuating physiological responses, suggesting potential for phytoremediation.

Abstract

The ecotoxicology model plant Lemna minor was exposed for 6 weeks to 90Sr, simulating the dose rates present in the Chernobyl Exclusion Zone (CEZ), in order to understand the effects of chronic low dose ionising radiation exposure. The data suggest that the plant may exhibit temporally variable acclimation responses that can be interpreted as early-, mid-, and long-term phases. Morphological changes included increased area and frond number, while molecular adjustments encompassed variations in pigment levels, glutathione metabolism, and expression modulation of telomerase-related and DNA methylation machinery genes. Physiological parameters and 90Sr uptake remained relatively stable, yet fluctuations indicate a continuous adjustment to the chronic stress, suggesting L. minor’s potential for phytoremediation. The interplay between transcriptional regulation of DNA methylation and the examined endpoints suggests a potential involvement of epigenetic mechanisms in L. minor’s acclimation to chronic low dose-rate 90Sr stress. This work provides knowledge on L. minor’s abiotic stress responses and contributes to our understanding of plant adaptation to low-level ionising radiation (IR). The findings contribute to the development of adverse outcome pathways (AOPs) for L. minor exposed to IR, improving environmental risk assessment approaches.

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