The group around QIN Guozheng studying the abscisic pathway (ABA) involved in fruit ripening found shown that mRNA m6A methylation, which is considered as an mRNA “epitranscriptome”, participates in the ripening control. The researchers found that m6A methylation displays a dramatic change at ripening onset of strawberry. The m6A modification in the coding sequence regions appears to be ripening-specific and tends to stabilize the mRNAs, whereas m6A around the stop codons and within the 3′ untranslated regions is generally negatively correlated with the abundance of the mRNAs. They identified thousands of transcripts with m6A hypermethylation in the coding sequence regions, including those of NCED5, ABAR, and AREB1 in the ABA biosynthesis and signaling pathway. Further analysis demonstrated that the methyltransferases MTA and MTB are indispensable for normal ripening of strawberry fruit, and MTA-mediated m6A modification promotes mRNA stability of NCED5 and AREB1, while facilitates translation of ABAR.
CAS news release, June 9, 2021