Genome-Wide Identification of Dopamine β-Monooxygenase N-Terminal Gene Family in Rice and Its Role in Response to Blast Disease and Abiotic Stress

Dopamine β-monooxygenase N-terminal (DOMON) domain-containing genes are found in all taxa and are crucial in cell signalling and redox transport. Despite its significance, these genes are unexplored in plant species remain understudied. In this study, we identified 15 DOMON genes in rice, and analyzed their phylogeny, conserved motifs, and cis -regulatory elements. Phylogenetic analysis revealed distinct clustering of OsDOMON genes in rice and other monocots compared to Arabidopsis thaliana . Promoter analysis showed a higher abundance of stress-related regulatory elements in Tetep, a well-known blast and abiotic stress tolerant cultivar, compared to Nipponbare and HP2216. OsDOMON genes are differentially expressed under biotic ( Magnaporthe oryzae infection) and abiotic (drought, heat, and salt) stresses in contrasting cultivars. Tetep exhibited significantly higher expression levels of a few OsDOMON genes during early blast infection stages particularly for OsDOMON6.1 and OsDOMON9.2 , suggesting their roles in cell wall fortification and ROS signaling. Under abiotic stress, genes such as OsDOMON3.3 , OsDOMON8.1 , and OsDOMON9.2 were highly expressed in Tetep, indicating their involvement in stress tolerance mechanisms. This study provides insights into the potential roles of OsDOMON genes in stress resilience and establishes a foundation for functional studies aimed at developing rice cultivars resistant to biotic and abiotic stresses.