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Dark-Induced Senescence Causes Localized Changes in DNA Methylation.
Minerva S Trejo-Arellano1, Saher Mehdi2, Jennifer de Jonge2
1Swedish University of Agricultural Sciences, Department of Plant Biology and Linnean Center for Plant Biology, SE-75007 Uppsala, Sweden minerva.trejo@slu.se.
Plant Physiology
|December 4, 2019
Summary
Plant senescence involves programmed tissue dismantling. This study reveals dark-induced senescence globally alters chromatin structure but only locally affects DNA methylation, reactivating transposable elements.
Area of Science:
- Plant biology
- Epigenetics
- Molecular biology
Background:
- Senescence is a programmed process in plants, crucial for nutrient reallocation and reproductive success.
- External factors can induce senescence as an adaptive strategy, suggesting multilevel control.
- Epigenetic reprogramming of the senescent genome is proposed, but mechanisms remain unclear.
Purpose of the Study:
- To investigate epigenetic changes, specifically DNA methylation, during dark-induced senescence in Arabidopsis leaves.
- To assess the impact of these epigenetic alterations on gene and transposable element (TE) expression.
Main Methods:
- Bisulphite conversion followed by sequencing to analyze the methylome.
- Transcriptome sequencing to monitor gene and TE expression.
- Comparative analysis of senescent versus non-senescent leaves.
Main Results:
- Dark-induced senescence led to down-regulation of genes controlling chromatin silencing.
- Transposable element (TE) silencing was impaired, with preferential reactivation of young TEs.
- Heterochromatin decondensed, global DNA methylation remained stable, with localized CHH methylation changes.
Conclusions:
- Plant senescence involves global chromatin structure changes but only localized DNA methylation alterations.
- The study highlights the dynamic nature of DNA methylation during plant development and senescence.
- Impaired TE silencing during senescence offers insights into genome stability and epigenetic regulation.
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