Objective  Changes in contents of main pigments and the expressions of related genes in pericarp of eggplant fruit during growth and development were studied concerning the color formation.

  Method  Contents of anthocyanin, chlorophyll, and carotenoid in the fruits of two high-generation eggplant inbred lines, green Qidong and purple-black 8 guo, were measured at 15, 20, 25, 30, and 35 d after pollination. Expressions of the structural genes PAL, CHS, CHI, F3H, DFR, and ANS and the transcription factors MYB75, JAF13, and WD40 related to anthocyanin synthesis, as well as the key gene, HEMA1, in chlorophyll synthesis and PSY1 in carotenoid synthesis were analyzed.

  Result  The contents of 3 categories of pigments in Qidong increased initially followed by a decline during the test period with peaks on the 20 d on anthocyanin, 25 d on chlorophyll, and 20 d on carotenoid. For 8 guo, the anthocyanin peaked on the 25 d, but chlorophyll and carotenoid continuously increased throughout the fruit development. 8 guo had higher relative contents of anthocyanin, lower chlorophyll from 15 d to 25 d, and higher carotenoid between 30 d and 35 d than Qidong. The expressions of anthocyanin synthesis structural genes and transcription factors MYB75, JAF13 and WD40 in Qidong were generally lower and relatively stable than those in 8 guo at different growth and development stages. The expression of anthocyanin synthesis structural genes in 8 guo reached a maximum on the 20 d and then began to decrease, while the expression of transcription factors MYB75 and WD40 rose at first and then decreased, which was similar to the trend observed on the anthocyanin. The expressions of HEMA1 and PSY1 in Qidong and 8 guo differed in the changing patterns of chlorophyll and carotenoid.

  Conclusion  During growth and development, the two eggplant varieties of different colored skins underwent significantly different changes on the 3 pigments. The expressions of the pigment-related genes differed significantly as well, which could be studied from a genetic perspective to reveal the underline mechanisms of the observed color formation and differentiation.