RNA demethylation induces increased crop biomass and productivity in the field

We performed the transcriptome-wide m6A profiling (MeRIP) with poly(A) RNA samples isolated from shoots and roots of wild type (Nipp), FTO homogeneous transgenic (FTO) and demethylation activity dead mutant variant of FTO transgenic (FTOmut) rice plants. The m6A motif and the distribution of the detected m6A sites along transcripts were consistent with reported results from previous m6A sequencing studies in plants. We then analyzed the differentially methylated m6A sites in poly(A) RNA species including those transcribed from gene loci and from repetitive elements (repeat RNAs). Compared to Nipp plants, both shoots and roots of FTO transgenic plants had showed more hypomethylated m6A peaks (hypo-m6A, 222 in shoots and 3313 in roots) than hypermethylated m6A peaks (hyper-m6A, 63 in shoots and 127 in roots) in mRNAs, while FTOmut rice had showed more hyper-m6A in shoots (349 for hyper vs 31 for hypo) but more hypo-m6A in roots (291 for hyper vs 380 for hypo) than the WT. The hypomethylated m6A peaks in FTO transgenic plants were highly enriched within 3'UTR. Gene Ontology (GO) analysis of these identified hypomethylated m6A-containing coding genes in both FTO transgenic rice shoots and roots revealed an enrichment for functional annotations related to “cellular homeostatic process”, “one-carbon and small molecule metabolic process”, and “gene expression”. We also found the extent of m6A hypomethylation was more pronounced for repeat RNAs than for mRNA species.The quantitative RNA-seq analysis that included ERCC spike-in controls confirmed that FTO plants do indeed accumulate higher overall levels of poly(A) RNA than do WT shoots and roots. Above all, FTO mediated m6A demethylation in plant mRNA and repeats RNA, leading to the activation of transcription. Overall design: Gene expression and m6A peaks were identified from RNA-seq and m6A-seq data, respectively. Both types of data were from the shoots and roots of wild type, FTO homogeneous transgenic and demethylation activity dead mutant variant of FTO homogeneous transgenic rice in two replicates.