Transcriptome-Wide N6-Methyladenosine (m6A) Methylome Profiling of Heat Stress in Pak-choi (Brassica rapa ssp. chinensis).

Background: In higher eukaryotes, N6-methyladenosine (m6A) is the most common internal form of messenger RNA modification. By mapping the m6A methyl genome in multiple species, the potential regulatory function of reversible m6A methylation on mRNA is revealed. Recent studies have shown that RNA m6A modification influences mRNA transcription, location, translation, stability, splicing, and nuclear export. However, there are not enough data on the m6A transcriptome-wide map and its potential biological role in the heat stress of Pak-choi (Brassica rapa ssp. chinensis). Methods: In this work, MeRIP-seq was used to obtain the first transcriptome-wide profiling of RNA m6A modification in Pak-choi. Meanwhile, the transcriptome data were obtained by analyzing the input samples’ sequencing data. Results: Our research indicated that with three replicates, there were 11,252 common m6A peaks and 9729 common m6A-containing genes identified in the normal (CK) and heat stress (T43) groups. It was found that m6A peaks were highly enriched in the 3′ untranslated region in both CK and T43 groups. About 80% of the genes have one m6A site. The consensus sequence of m6A peaks was also enriched, which showed as AAACCV (V: U/A/G). In addition, association analysis found that there is a certain relationship between the degree of m6A methylation and the transcription level, indicating that m6A plays a certain regulatory role in gene expression. Conclusion: This comprehensive map in the study may provide a solid basis for determining the potential function of RNA m6A modification in Pak-choi under normal (CK) and heat stress (T43) conditions.