JmjC Domain-containing Histone Demethylase Gene Family in Chinese Cabbage: Genome-wide Identification and Expressional Profiling

The Jumonji C (JmjC) structural domain-containing gene family, an important family of histone demethylases in plants, has an essential role in plant growth and development, flowering transformation, and stress responses. Here, we aimed to elucidate its role in Chinese cabbage (Brassica rapa ssp. pekinensis). At the genome level, we identified 29 members of this family that have remained highly conserved. For these genes, the promoter cis-acting elements were enriched in responses to stress related to light and cold, anaerobic conditions, and phytohormone treatment. BrJMJs were highly expressed in the siliques and flowers, suggesting that histone demethylation might play a crucial role in reproductive organ growth. Stress associated with cadmium (Cd) exposure, drought, salinity, cold, and heat induced their expression. The expression of some of the genes (BrJMJ1/2/5/13/21/24) increased gradually with increasing Cd concentration. BrJMJ4 and BrJMJ29 were induced by drought, salt, cold, and heat stress. This work supports future analysis of the biological functions of JmjC family genes and elucidates the molecular mechanisms of abiotic stress responses in Chinese cabbage.