N6-methyladenosine RNA modification regulates strawberry fruit ripening in an ABA-dependent manner

Background Epigenetic marks, such as DNA methylation, play pivotal roles in regulating ripening of both climacteric and non-climacteric fruits. However, it remains unclear whether mRNA m 6 A methylation, the epitranscriptome, is functionally conserved for ripening control. Results Here we show that m 6 A methylation, which has been revealed to regulate ripening of tomato, a typical climacteric fruit, displays a dramatic change at ripening onset of strawberry, a classical non-climacteric fruit. The m 6 A modification in the coding sequence (CDS) regions appears to be ripening-specific and tends to stabilize the mRNAs, whereas m 6 A around the stop codons and within the 3’ untranslated regions is generally negatively correlated with the abundance of the mRNAs. We identified thousands of transcripts with m 6 A hypermethylation in the CDS regions, including those of NCED5 , ABAR , and AREB1 in the abscisic acid (ABA) biosynthesis and signaling pathway. We demonstrated that the methyltransferases MTA and MTB are indispensable for normal ripening of strawberry fruit, and MTA-mediated m 6 A modification promotes mRNA stability of NCED5 and AREB1 , while facilitates translation of ABAR . Conclusion Our findings uncover that m 6 A methylation regulates ripening of non-climacteric strawberry fruit by targeting ABA pathway, which is distinct from that in climacteric tomato fruit.