Mapping and validation of the epistatic and genes controlling anthocyanin biosynthesis in the peel of eggplant ( L.) fruit.

Fruit color is an important trait influencing the commercial value of eggplant fruits. Three dominant genes (, and ) cooperatively control the anthocyanin coloration in eggplant fruits, but none has been mapped. In this study, two white-fruit accessions (19 141 and 19 147) and their F progeny, with 9:7 segregation ratio of anthocyanin pigmented versus non-pigmented fruits, were used for mapping the and genes. A high-density genetic map was constructed with 5270 SNPs spanning 1997.98 cM. Three QTLs were identified, including two genes on chromosome 8 and one on chromosome 10. Gene expression analyses suggested that the on chromosome 8 and on chromosome 10 were the putative candidate genes for and , respectively. We further identified (1) a SNP leading to a premature stop codon within the conserved PLN03176 domain of in 19 141, (2) a G base InDel in the promoter region leading to an additional -regulatory element and (3) a 6-bp InDel within the R2-MYB DNA binding domain of , in 19 147. Subsequently, these three variations were validated by PARMS technology as related to phenotypes in the F population. Moreover, silencing of or in the purple red fruits of F (E3316) led to inhibition of anthocyanin biosynthesis in the peels. Conversely, overexpression of or restored anthocyanin biosynthesis in the calli of 19 141 and 19 147 respectively. Our findings demonstrated the epistatic interactions underlying the white color of eggplant fruits, which can be potentially applied to breeding of eggplant fruit peel color.