Pigment biofortification in rice, particularly through enhanced anthocyanin accumulation, is increasingly recognized in Asia for its potential to improve nutritional quality and antioxidant capacity while addressing regional health challenges. However, the regulatory network underlying anthocyanin biosynthesis in rice remains incompletely characterized, especially regarding MYB transcription factors that may control pigment accumulation in diverse germplasm. In this study, a genome-wide analysis of MYB transcription factors in Oryza sativa subsp. japonica identified 109 OsMYB genes. Phylogenetic comparison with known anthocyanin regulators from Arabidopsis thaliana and Oryza rufipogon revealed conserved clades containing potential pigment-related regulators. Integrative analyses including gene structure, conserved motif identification, promoter cis-element profiling, and miRNA target prediction were conducted to explore their regulatory potential. Expression profiling during grain development in black and mixed rice identified 32 OsMYB genes as potential candidates associated with anthocyanin accumulation. Promoter analysis revealed enrichment of light-responsive, stress-responsive, and developmental regulatory elements, suggesting coordinated regulation by environmental and developmental signals. Predicted interactions with several Osa-miRNAs further indicate potential post-transcriptional control of these genes. Among the candidates, OsMYB65 showed strong differential expression in pigmented rice grains and possessed multiple regulatory elements associated with anthocyanin biosynthesis, highlighting it as a promising regulator. Overall, this integrative genome-wide analysis identifies a prioritized set of MYB transcription factors that may regulate anthocyanin biosynthesis in rice, providing valuable targets for functional validation and pigment-oriented crop improvement.
Jayaprada et al. (Thu,) studied this question.