| Summary: | N6-methyladenosine (m6A) is a dynamic, reversible,
covalently modified ribonucleotide that occurs predominantly
toward 30 ends of eukaryotic mRNAs
and is essential for their proper function and regulation.
In Arabidopsis thaliana, many RNAs contain at
least one m6A site, yet the transcriptome-wide function
of m6A remains mostly unknown. Here, we show
that manym6A-modified mRNAs in Arabidopsis have
reduced abundance in the absence of this mark. The
decrease in abundance is due to transcript destabilization
caused by cleavage occurring 4 or 5 nt directly
upstream of unmodified m6A sites. Importantly, we
also find that, upon agriculturally relevant salt treatment,
m6A is dynamically deposited on and stabilizes
transcripts encoding proteins required for salt
and osmotic stress response. Overall, our findings
reveal that m6A generally acts as a stabilizing mark
through inhibition of site-specific cleavage in plant
transcriptomes, and this mechanism is required
for proper regulation of the salt-stress-responsive
transcriptome.
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