Abstract: The covalent modifications of histone in plants have changed dynamically during the development and adaption to dehydration stress. However, the histone modification enzymes involved in dehydration stress are mostly unknown. Here, we show that the SDG8, responsible for di- and tri-methylation of H3 lysine36, is involved in dehydration stress in Arabidopsis. The expression analysis shows that mutations in SDG8 result in altering a cluster of gene transcripts, including genes in salt, cold, and dehydration stress. Loss-of-function of SDG8 displays faster transpiration, larger stomatal apertures, less sensitivity to the ABA treatment, and decreased tolerance to dehydration stress. Together, our study suggests that SDG8 might be a novel factor involved in the dehydration stress process.