Aging drives a program of DNA methylation decay in plant organs

Plants display a wide range of life spans and aging rates. Although dynamic changes to DNA methylation are a hallmark of aging in mammals, it is unclear whether similar molecular signatures reflect rates of aging and organism life span in plants. In this work, we show that the short-lived model plant <i>Arabidopsis thaliana</i> exhibits a loss of epigenetic integrity during aging, which causes DNA methylation decay and the expression of transposable elements. We show that the rate of epigenetic aging can be manipulated by extending or curtailing life span and that shoot apical meristems are protected from these epigenetic changes. We demonstrate that a program of transcriptional repression suppresses DNA methylation maintenance pathways during aging and that mutants of this program display a complete absence of epigenetic decay while physical aging remains unaffected.