Transcriptome-wide analysis of mRNA N 6 -methyladenosine modification in the embryonic development of Spodoptera frugiperda.

N 6 -methyladenosine (m 6 A) RNA is the most abundant modification of mRNA, and has been demonstrated in regulating various post-transcriptional processes. Many studies have shown that m 6 A methylation plays key roles in sex determination, neuronal functions, and embryonic development in Drosophila and mammals. Here, we analyzed transcriptome-wide profile of m 6 A modification in the embryonic development of the destructive agricultural pest Spodoptera frugiperda. We found that the 2 key mRNA m 6 A methyltransferases SfrMETTL3 and SfrMETTL14 have high homologies with other insects and mammals, suggesting that SfrMETTL3 and SfrMETTL14 may have conserved function among different species. From methylated RNA immunoprecipitation sequencing analysis, we obtained 46 869 m 6 A peaks representing 8 587 transcripts in the 2-h embryos after oviposition, and 41 389 m 6 A peaks representing 9 230 transcripts in the 24-h embryos. In addition, 5 995 m 6 A peaks were differentially expressed including 3 752 upregulated and 2243 downregulated peaks. Functional analysis with Gene Ontology and Kyoto Encyclopedia of Genes and Genomes suggested that differentially expressed m 6 A peak-modified genes were enriched in cell and organ development between the 2- and 24-h embryos. By conjoint analysis of methylated RNA immunoprecipitation-seq and RNA-seq data, we found that RNA m 6 A methylation may regulate the transcriptional levels of genes related to tissue and organ development from 2- to 24-h embryos. Our study reveals the role of RNA m 6 A epigenetic regulation in the embryonic development of S. frugiperda, and provides new insights for the embryonic development of insects.