Map-based cloning reveals gene encoding an APRR2 protein to regulate the green fruit peel formation in .

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Fruit peel color is a major factor that influences fruit quality and customers' demand. However, the molecular mechanisms underlying the green fruit peel color trait of L. remain unknown. Two parental lines, RP16 and RP38, were used to study the fruit peel color trait in . The parental line RP16 shows white peel color, whereas RP38 exhibits green peel color. 384 F populations were used to identify the inheritance pattern associated with green fruit and white fruit peel in L. 293 F individuals were white, and 91 F individuals were green, resulting in a ratio of 3:1. Hence, white peel is dominant over the green fruit peel trait, and a single recessive green peel gene () controls the green fruit peel. The fruit chlorophyll (Chll) content decreases as fruit matures in the RP16 line. In contrast, Chll increases during the fruit growing periods on fruit peels of the RP38 line. The BSA-sequence analysis revealed the locus on Chr5, within a 2.3 Mb region. Subsequent fine-mapping analysis, using 699 F plants, narrowed down this region to 23.90 kb on the same chromosome. Within this region, two annotated genes, namely and , are present. These genes are predicted to encode a two-component Arabidopsis Pseudo-Response Regulator 2-like protein (APRR2), which may be involved in green pigmentation processes in plants. Consequently, sequence alignment and gene expression analyses at various fruit development stages supported that may be the primary candidate gene responsible for regulating the green fruit peel color trait in L. This study may provide a basis for further study on the basic mechanisms that control the fruit peel colors in .

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The online version contains supplementary material available at 10.1007/s11032-024-01492-7.