Fine-mapping and primary analysis of candidate genes associated with seed coat color in mung bean (Vigna radiata L.)

Seed coat color affects the appearance and commodity quality of mung beans (Vigna radiata L.). The substances that affect mung bean seed coat color are mainly flavonoids, which have important medicinal value. Mapping the seed coat color gene in mung beans would facilitate the development of new varieties and improve their value. In this study, an F2 mapping population consisting of 546 plants was constructed using Jilv9 (black seed coat) and BIS9805 (green seed coat). Using bulk segregated analysis (BSA) sequencing and kompetitive allele-specific PCR (KASP) markers, the candidate region related to seed coat color was finally narrowed to 0.66 Mb on chromosome (Chr.) 4 and included eight candidate genes. Combined transcriptome and metabolome analyses showed that three of the eight candidate genes (LOC106758748, LOC106758747, and LOC106759075) were differentially expressed, which may have caused the differences in flavonoid metabolite content between Jilv9 and BIS9805. These findings can provide a research basis for cloning the genes related to seed coat color and accelerate molecular marker-assisted selection breeding in mung beans.