Genomic insights into phenolic content: Multi-environment based marker-trait association mapping in rice (Oryza sativa L.)

Phenolic acids are crucial for human health due to their potent antioxidant, anti-inflammatory, and antimicrobial properties, which help protect against chronic diseases and support overall well-being. In this study, 44 rice accessions were evaluated for total phenolic content in three different locations of Tamil Nadu and the marker trait association was done using 208 SSR markers. Among the association panel, Mappillai Samba was identified as having the highest total phenolic content of 1049.936 mg GAE/100 g. The phylogenetic analysis grouped the panel of entries into five genetic structure groups which nearly matched the geographical distance among the entries. Marker-trait association studies using GLM and MLM revealed that SSR markers RM287 and RM19358 were significantly associated with total phenolic content, explaining 23.4% and 19.7% of the observed variability, respectively. These markers were located in genomic regions linked to candidate genes involved in the biosynthesis of trans-cinnamate 4- monooxygenase (C4H) and phenylalanine ammonia-lyase (PAL), key enzymes in the phenolic acid pathway. Identifying these markers provides valuable tools for marker-assisted selection, enabling the development of biofortified rice varieties with enhanced phenolic content. Such advancements promise to improve rice nutritional quality and promoting public health through dietary interventions.