Stress induced gene expression drives transient DNA methylation changes at adjacent repetitive elements

Area of Science:

• Epigenetics
• Plant molecular biology
• Environmental stress response

Background:

• Cytosine DNA methylation (mC) regulates gene expression but its role in environmental response is unclear.
• Transposable elements (TEs) are mobile genetic sequences influenced by epigenetic modifications.
• Understanding epigenetic plasticity under stress is crucial for crop adaptation.

Purpose of the Study:

• To investigate the dynamics of mC in rice under phosphate starvation.
• To determine the relationship between mC changes, gene transcription, and environmental stress.
• To assess the species-specificity of mC responses to nutrient deficiency.

Main Methods:

• Whole genome bisulfite sequencing (WGBS) to map mC.
• Analysis of rice and Arabidopsis under phosphate starvation and recovery.
• Correlation of mC changes with gene expression and TE localization.

Main Results:

• Phosphate starvation induced significant mC changes in rice TEs near highly induced genes.
• mC alterations followed transcriptional changes and were mostly DCL3a-independent.
• Mitotic propagation of mC changes was observed, but not meiotic transmission.
• Arabidopsis showed minimal mC response to phosphate starvation, indicating species specificity.

Conclusions:

• TEs near environmentally responsive genes are silenced via hypermethylation during phosphate starvation in rice.
• Epigenetic modifications (mC) play a role in the plant stress response, with a defined temporal order relative to transcription.
• The observed mC regulation is a species-specific mechanism in rice, highlighting evolutionary divergence in epigenetic responses to environmental cues.