Comprehensive Genome-Wide Identification and Expression Analysis of the N6-Methyladenosine (m6A) Regulatory Network Influences Rapid Stress Adaptation With Exogenous Melatonin in Rice.

Exogenous melatonin has emerged as a pivotal multifunctional signaling molecule, recognized for its critical role in enhancing stress tolerance and improving crop productivity. N6-methyladenosine (m6A) is the most prevalent internal modification found in eukaryotic mRNA and plays a crucial role in regulating plant growth, development, and stress responses. Despite its importance, the regulatory mechanisms of the m6A pathway in rice exposed to exogenous melatonin remain inadequately investigated. This study investigates systematic analysis of m6A-regulatory gene families in rice. We identified a total of 124 genes, which include 7 writers, 22 readers, and 95 erasers. The distribution of these genes is uneven across the 11 chromosomes of the rice genome. Analysis of conserved domains revealed structural signatures that are specific to each gene family. Phylogenetic relationships with dicot and monocot species offered insights into evolutionary trajectories. Notably, gene structure and motif analyses revealed functional divergence within and between gene families. Cis-element analysis identified abundance motifs associated with stress adaptation, hormonal signaling, and TFs, including ABRE, DRE, and MYB. Furthermore, synteny analysis unveiled both conserved regions and lineage-specific expansions, particularly within the YTH and ALKBH families. The protein interaction network revealed robust connections among subgroups and identified 10 hub genes. GO and KEGG analyses indicated significant enrichment in stress-related pathways, including secondary metabolite biosynthesis, flavonoid biosynthesis, and cysteine and methionine metabolism. RT-qPCR validates that melatonin Osm6As significantly influences the expression of targeted genes, with melatonin upregulations exhibiting a time-dependent pattern. Furthermore, GFP tagging of OsECT2 revealed that protoplasts are evenly distributed, suggesting robust nuclear enrichment of fluorescence. This study offers new insights into the epitranscriptomic regulatory responses of the m6A-modifier.