DNA methylation on N6-adenine (6mA) has recently been found as a potentially new epigenetic mark in several unicellular and multicellular eukaryotes. However, its distribution patterns and potential functions in land plants, which are primary producers for most ecosystems, remain completely unknown. Here we report global profiling of 6mA sites at single-nucleotide resolution in the genome of Arabidopsis thaliana using single-molecule real-time sequencing. 6mA sites are widely distributed across the Arabidopsis genome and enriched over the pericentromeric heterochromatin regions. Nearly 30% of 6mA sites are present in gene bodies. Further analysis of 6mA methylome and RNA-sequencing data demonstrates that 6mA frequency positively correlates with the gene expression level in Arabidopsis. Consistently, histone variants associated with actively expressed genes interact with 6mA DNA. Our results uncover 6mA as a DNA mark associated with actively expressed genes in Arabidopsis, suggesting that 6mA serves as a novel epigenetic mark in land plants. Overall design: RNA-seq in 3-week-old Arabidopsis thaliana (Col-0) wild-type with three replicates.