Genome-wide DNA N6-adenine methylation in sea buckthorn (Hippophae rhamnoides L.) fruit development.

ABSTRACT

As a new epigenetic mark, DNA N6-adenine (6mA) methylation plays an important role in various biological processes and has been reported in many prokaryotic organisms in recent years. However, the distribution patterns and functions of DNA 6mA modification have been poorly studied in non-model crops. In this study, we observed that the methylation ratio of 6mA was about 0.016% in the sea buckthorn (Hippophae rhamnoides L.) genome using mass spectrometry. We first constructed a comprehensive 6mA landscape in sea buckthorn genome using nanopore sequencing at single-base resolution. Distribution analysis suggested that 6mA methylated sites were widely distributed in the sea buckthorn chromosomes, which were similar to those in Arabidopsis and rice. Furthermore, reduced 6mA DNA methylation is associated with different expression of genes related to the fruit-ripening process in sea buckthorn. Our results revealed that 6mA DNA modification could be considered an important epigenomic mark and contributes to the fruit ripening process in plants.