Identification of a locus associated with chlorosis and antioxidant capacity using RNA-seq and BSA-seq in soybean [Glycine max (L.) Merr]

Plant coloration is an important trait in soybean ( Glycine max ), and its underlying molecular mechanisms are complex. In this study, we identified a chlorotic mutant, el-5y , in the wild-type soybean cultivar VS-5. Compared with those in VS-5, the capacities for photosynthesis, photosynthetic pigment synthesis, and antioxidant production in the el-5y mutant were significantly decreased, leading to a significant decrease in production. Transmission electron microscopy showed that the el-5y mutant cells were malformed, and abnormal lamellae and starch granules in the chloroplasts were significantly increased. Transcriptome analysis indicated that the differentially expressed genes (DEGs) between VS-5 and the el-5y mutants were mainly enriched in pathways related to the reduction–oxidation system, iron ion homeostasis, and auxin signaling transport. Based on the bulked segregant analysis data, the el-5y mutant was mapped to a 1.16-Mb interval on chromosome 11. The results of this study serve as a basis for further explorations into the molecular mechanisms that regulate plant coloration.