Naturally Occurring Epialleles and Their Roles in Response to Climate Change in Birch

Area of Science:

• Plant epigenetics
• Climate change adaptation
• Forest ecology

Background:

• Epigenetics enables plant adaptation to environmental changes, sometimes independent of genetic variation.
• The role of epigenetics in forest tree adaptation to global climate change remains understudied.
• White birch (Betula platyphylla) is a key pioneer species sensitive to global warming.

Purpose of the Study:

• To investigate the extent of epigenetic uncoupling from genetic variation in white birch.
• To assess the contribution of epigenetics to white birch adaptation to climate change.
• To identify potential epialleles associated with climate variables and predict species vulnerability.

Main Methods:

• High-quality genome assembly of Betula platyphylla.
• Multi-omics sequencing across 48 natural provenances.
• Genome-wide association study (GWAS) to identify differentially methylated regions (DMRs) and epialleles.
• Gradient modeling integrating epigenomic and bioclimatic data.

Main Results:

• Over 55% of DMRs were spontaneous and independent of genetic factors.
• More than 30% of spontaneous DMRs were associated with gene expression (epialleles), mainly in metabolism and stress response.
• 1819 epialleles (climatic epialleles, cEpialleles) were significantly associated with bioclimatic variables.
• White birch populations at high altitude/latitude may be vulnerable to future climate change.

Conclusions:

• Epigenetic modifications are crucial for plant adaptation to climate fluctuations.
• Spontaneous epialleles in white birch are linked to climate variables, indicating adaptive potential.
• Integrating epigenomic and climatic data is essential for forecasting forest species' adaptive capacity to climate change.