Multigenerational UV stress effects in Arabidopsis thaliana offspring
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Date
2024
Authors
Lopez Virgen, Andres Guadalupe
University of Lethbridge. Faculty of Arts and Science
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Lethbridge, Alta. : University of Lethbridge, Dept. of Biological Sciences
Abstract
Continuous exposure to environmental stress contributes to species diversity and drives microevolutionary processes. However, whether epigenetic alterations, such as differential DNA methylation, are prerequisites for speciation events remains unclear. We hypothesized that prolonged stress exposure would increase epigenetic diversity more than genetic diversity. In this study, we analysed the effects of 25 consecutive generations of UV-C stress on the genome and epigenome of Arabidopsis thaliana. Our results showed that multigenerational UV-C exposure led to significant genetic and epigenetic changes in the progeny. Genomic analysis of the UV-stressed progeny (F25UV) revealed a higher frequency of genetic variations compared to controls (F25C, F2C), with deletions being more prevalent than insertions, probably due to the mechanisms of DNA damage and repair processes triggered by UV radiation. F25UV also exhibited a significantly higher proportion of nonsense mutations, with C-to-T transitions being the most common, likely due to deamination of methylated cytosines. Epigenomic analysis showed that F25UV plants had more differentially methylated cytosines (DMCs) across all contexts than the F2C group. F25UV also had more DMCs than the F25C group in the CHG and CHH contexts, with the most striking difference in the CHH context, where F25UV had over 10-fold more DMCs than the F25C group. Despite these genetic and epigenetic changes, no differences in progeny resilience under stress were observed, based on root analysis, reactive oxygen species levels, and overall growth at both the seedling and mature stages. Our findings suggest that UV radiation stress can induce genetic and epigenetic changes that are capable of being inherited in transgenerational manner. Although these changes did not result in more resilient plants, their non-random nature suggests an evolutionary and adaptive direction.
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Keywords
environmental stress exposure , epigenetic diversity , genetic diversity , UV radiation stress , speciation , progeny resilience