Fine Mapping and Identification of SmAPRR2 Regulating Rind Color in Eggplant (Solanum melongena L.)

Rind color is an economically important agronomic trait in eggplant that impacts consumer preferences. In this study, bulked segregant analysis and competitive allele-specific PCR were employed to identify the candidate gene for eggplant rind color through constructing a 2794 F-2 population generated from a cross between BL01 (green pericarp) and B1 (white pericarp). Genetic analysis of rind color revealed that a single dominant gene controls green color of eggplant peel. Pigment content measurement and cytological observations demonstrated that chlorophyll content and chloroplast number in BL01 were higher than in B1. A candidate gene (EGP19168.1) was fine-mapped to a 20.36 Kb interval on chromosome 8, which was predicted to encode the two-component response regulator-like protein Arabidopsis pseudo-response regulator2 (APRR2). Subsequently, allelic sequence analysis revealed that a SNP deletion (ACT -> AT) in white-skinned eggplant led to a premature termination codon. Genotypic validation of 113 breeding lines using the Indel marker closely linked to SmAPRR2 could predict the skin color (green/white) trait with an accuracy of 92.9%. This study will be valuable for molecular marker-assisted selection in eggplant breeding and provides theoretical foundation for analyzing the formation mechanism of eggplant peel color.

Automated summary

In this study, the candidate gene for eggplant rind color was identified through bulked segregant analysis and competitive allele-specific PCR. The results showed that a single dominant gene controls green color of eggplant peel. The candidate gene (EGP19168.1) was fine-mapped to a specific interval on chromosome 8 and was predicted to encode a protein related to response regulation. This study provides valuable insights for molecular marker-assisted selection in eggplant breeding and contributes to understanding the formation mechanism of eggplant peel color.