Chloroplast Demethylation Boosts Plant Stress Resilience

A key chemical tag on messenger RNA, called m6A, is common across all eukaryotes. Cells control how much of this tag appears by adding or removing it with specialized enzymes known as writers and erasers. In plant cells, the chloroplast—a site of photosynthesis—contains many mRNAs that carry this tag, but scientists did not know what it does there. To investigate, researchers took an enzyme that normally removes the tag in the nucleus and cytoplasm of Arabidopsis plants. They engineered this enzyme to travel into chloroplasts, creating a new tool that could erase the tag inside this organelle. The modified enzyme worked as expected, stripping the tag from many chloroplast mRNAs.The removal of the tag had a clear benefit. Plants with the engineered enzyme survived better under salty and dry conditions. The improved tolerance is linked to changes in how stable the mRNAs that control photosynthesis remain. When the tag was removed, these messages stayed intact longer, helping the plant keep its photosynthetic machinery running during stress. These findings suggest that tweaking RNA tags inside chloroplasts can strengthen a plant’s ability to cope with environmental challenges. The approach offers a promising strategy for breeding crops that can withstand drought and salinity.