Browning has been the primary limitation in eggplant processing. This study investigates the molecular mechanism underlying fresh-cut eggplant fruit browning by observing the physicochemical characteristics of browning-resistant (‘F’) and browning-sensitive (‘36′) eggplant cultivars. Browning-related enzyme activity and gene expression (PPO, LOX, and PLD) were significantly higher in the ‘36′ eggplant, thereby enhancing the degree of browning, compared to the ‘F’ eggplant. The MDA content and O₂⁻ production rate progressively increased as browning increased, while the antioxidant capacity of the fruit decreased. The cutting injury significantly activated the expression of PAL, thereby inducing the accumulation of phenolic acids, while the PPO gene was significantly upregulated, which activated the activity of polyphenol oxidase. Our results showed that the oxidation of chlorogenic acids to chlorogenic quinones resulted in the occurrence of browning, which suggests chlorogenic acid as the main browning substrate in fresh-cut eggplant.

Fruit color is an intuitive quality of horticultural crops that can be used as an evaluation criterion for fruit ripening and is an important factor affecting consumers’ purchase choices. In this study, a genetic population from the cross of green peel ‘Qidong’ and purple peel ‘8 guo’ revealed that the purple to green color of eggplant peel is dominant and controlled by a pair of alleles. Bulked segregant analysis (BSA), SNP haplotyping, and fine genetic mapping delimited candidate genes to a 350 kb region of eggplant chromosome 10 flanked by markers KA2381 and CA8828. One ANS gene (EGP22363) was predicted to be a candidate gene based on gene annotation and sequence alignment of the 350-kb region. Sequence analysis revealed that a single base mutation of ‘T’ to ‘C’ on the exon green peel, which caused hydrophobicity to become hydrophilic serine, led to a change in the three-level spatial structure. Additionally, EGP22363 was more highly expressed in purple peels than in green peels. Collectively, EGP22363 is a strong candidate gene for anthocyanin biosynthesis in purple eggplant peels. These results provide important information for molecular marker-assisted selection in eggplants, and a basis for analyzing the regulatory pathways responsible for anthocyanin biosynthesis in eggplants.

Expansins are essential regulators of plant cell wall loosening, yet their roles in eggplant (Solanum melongena L.) remain poorly understood. This study performed a genome-wide analysis and identified 26 SmEXP genes, categorized into five evolutionary groups. All SmEXP proteins harbor characteristic DPBB_1 and Expansin_C domains. These genes are unevenly distributed across 10 chromosomes out of the 12 eggplant chromosomes, with Chromosome 8 identified as a major distribution hotspot. Synteny and selection pressure analyses suggest that segmental duplications and strong purifying selection have driven the family’s evolution. Promoter analysis revealed various cis-acting elements associated with light, phytohormones, and abiotic stress. Transcriptomic profiling showed that 14 SmEXP genes were significantly upregulated during the rapid fruit expansion phase (14 DAP), indicating their crucial role in fruit morphogenesis. Furthermore, some specific members (SmEXP1, 4, 10, and 13) exhibited distinct upregulation under heat stress (38 °C and 43 °C), suggesting involvement in thermotolerance. These findings identify key expansin genes controlling eggplant development and stress response, providing targets for genetic improvement.