Difference of PmTDC1 expression levels results the formation of brown and yellow seed color in broomcorn millet(Panicum miliaceum)

[Objective]Broomcorn millet is a cereal crop with abundant genetic variation in morphology,agronomy and yield-related traits.Diversity of seed color is one of the most distinctive morphological characteristic.To identify genes regulating seed color will provide a basis for precise identification of germplasms at molecular level,molecular assisted selection breeding and application of gene editing technology in broomcorn millet.[Method]Phenotype identification and statistical analysis were used to dissect inheritance law.And bulked segregant analysis sequencing(BSA-seq),substitution mapping and transcriptome sequencing were performed to identify the casual gene of brown yellow grain color in broomcorn millet.[Result]Here,F2 and F3 populations from a cross between Longmi12 and Zhang778 were constructed.The statistical analysis of the seed color in F1,F2 and F3 progenies confirmed that the brown seed color was controlled by a dominant single gene in broomcorn millet.The genetic control locus,SC9.1,was preliminarily located in the interval between 32175878 to 44281406 bp on chromosome 9 through the bulked segregant analysis sequencing(BSA-seq).Further,SC9.1 was narrowed down to a 101kb interval harboring 11 genes by substitution mapping based on 258 recessive individual genotypes.Of 11 genes,PmTDC1 had a single A to G transition in CDS region and a significantly different expression in seed color formation stage,indicating that PmTDC1 was the causal gene resulting brown and yellow seed color formation in broomcorn millet.[Conclusion]Difference of PmTDC1 expression levels results the formation of brown and yellow seed color in broomcorn millet.