N6-methyladenosine RNA modification regulates photosynthesis during photodamage in plants

Abstract

N6-methyladenosine (m6A) modification of mRNAs affects many biological processes. However, the function of m6A in plant photosynthesis remains unknown. Here, we demonstrate that m6A modification is crucial for photosynthesis during photodamage caused by high light stress in plants. The m6A modification levels of numerous photosynthesis-related transcripts are changed after high light stress. We determine that the Arabidopsis m6A writer VIRILIZER (VIR) positively regulates photosynthesis, as its genetic inactivation drastically lowers photosynthetic activity and photosystem protein abundance under high light conditions. The m6A levels of numerous photosynthesis-related transcripts decrease in vir mutants, extensively reducing their transcript and translation levels, as revealed by multi-omics analyses. We demonstrate that VIR associates with the transcripts of genes encoding proteins with functions related to photoprotection (such as HHL1, MPH1, and STN8) and their regulatory proteins (such as regulators of transcript stability and translation), promoting their m6A modification and maintaining their stability and translation efficiency. This study thus reveals an important mechanism for m6A-dependent maintenance of photosynthetic efficiency in plants under high light stress conditions.