Genome-wide analysis of Caffeic Acid O-Methyltransferase (COMT) gene family in rice(Oryza sativa L.): identification, expression analysis and response to drought stress

Abstract Background Plant lignin plays a crucial role in plant stress resistance, and Caffeic acid O-methyltransferase (COMT) is one of the core enzymes involved in lignin synthesis. However, there is no systematic study on the rice COMT gene family. Methods and results We identified 33 COMT genes containing Methyltransferase-2 domain in the rice genome using bioinformatic methods. Using cis-acting element analysis, we found that the rice COMT genes contain multiple drought-inducible MYB-binding site (MBS)-acting elements related to drought induction and hypothesized that the rice COMT genes are related to drought stress. The RNA level data and qRT-PCR showed that rice COMT genes were highly expressed in leaves and stems, the expression of OsCOMT21/5/2/17/19 increased and that of OsCOMT31/16/21 decreased under drought stress. Protein interaction networks are related to gene classification. Targeting miRNAs and gene ontology annotation revealed that OsCOMTs may also be involved in other abiotic stress responses. We also studied the 3D structure of OsCOMTs proteins. Conclusion Our study contributes to the analysis of the biological function of rice COMT genes, which may provide information for future rice breeding and editing of the rice genome.