DNA methylation contributes to plant acclimation to naturally fluctuating light (WGBS)

Plants experience dynamic light daily, with light conditions varying on a second-by-second basis. Little is understood about the mechanisms that allow plants to survive such variable conditions. Here, we have exposed Arabidopsis thaliana plants to naturally fluctuating light regimes alongside traditional square light regimes. The response was highly consistent across experiments, leading us to believe there is an epigenetic mechanism involved. We show significant alterations in DNA methylation between fluctuating light acclimated plants, and square light acclimated plants, demonstrating the frequency of fluctuations impacts the plant methylation. This was accompanied by significant changes in gene expression, some of which correlated with altered DNA methylation. Interestingly, several transposable elements which displayed differential methylation were found to be differentially expressed between light regimes. This data suggests DNA methylation may have a role in acclimation to natural light which may directly regulate gene expression and impact transposable element activation. Overall design: To investigate whether DNA methylation patterns are impacted by light regime, DNA was extracted from leaf tissue of Arabidopsis thaliana which had been acclimated to one of four growth light regimes for 22 days