Photorespiration is linked to DNA methylation by formate as a one-carbon source

Area of Science:

• Plant Physiology
• Epigenetics
• Metabolic Biochemistry

Background:

• Photorespiration is a metabolic process that reduces photosynthetic efficiency.
• Cellular one-carbon (C1) metabolism is crucial for various processes, including DNA methylation.
• The contribution of photorespiration-derived metabolites to C1 metabolism was previously unclear.

Purpose of the Study:

• To investigate the role of photorespiration in supplying C1 units for DNA methylation.
• To understand how environmental factors like elevated CO2 affect this metabolic link.

Main Methods:

• Utilized Arabidopsis as a model organism.
• Traced carbon flow from formate to DNA methylation using metabolic pathways.
• Analyzed methylome alterations under varying CO2 concentrations and metabolic conditions.

Main Results:

• Photorespiration directly supplies C1 units for DNA methylation via the C1-tetrahydrofolate synthase pathway.
• This pathway is primarily active during daylight hours.
• Elevated CO2, which suppresses photorespiration, leads to significant methylome changes, particularly when alternative C1 sources are limited.

Conclusions:

• Established a direct metabolic link between photorespiration and epigenome stability.
• Photorespiration is a key source of C1 metabolites for DNA methylation.
• Findings provide insights into methylome regulation under changing environmental conditions, such as rising CO2 levels.