Abstract

The regulation of DNA methylation plays crucial roles in response to various abiotic stress in plants. However, the underlying regulatory mechanisms remain unclear. Here, we reported that OsDML4, a DNA demethylase gene, is required for regulating rice salt tolerance . The osdml4 mutants were sensitive to salt stress, with abnormal accumulated levels of reactive oxygen species (ROS) and increased Na + /K + ratio. By using RNA-Seq for the identification of candidate targets of OsDML4 , we found that the expression of the ROS-scavenging-related gene OsCATA (fold change > 1.7, p-value < 0.05) and JA-related gene OsJAZ13 (fold change > 2.8, p-value < 0.05) was significantly reduced in the osdml4 mutant under salt stress. Moreover, the CHH methylation in the promoter region of OsCATA was increased under salt stress, and it was much more significant in the osdml4 mutant (from 3.24% to 6.25%) than in the Nip (from 3.12% to 4.16%). Together, OsDML4 may directly or indirectly regulate ROS homeostasis and the JA signaling to improve salt tolerance in rice, which would provide new insight for further research on the role of the demethylase gene in response to abiotic stress.