Anthocyanin synthesis is affected by many factors, among which temperature is an important environmental factor. Eggplant is usually exposed to high temperatures during the cultivation season in Shanghai, China. Therefore,RNA -seq analysis was used to determine the effects of high-temperature stress on gene expression in the anthocyanin biosynthetic pathway of eggplant (Solanum melongena L.). We tested the heat-resistant cultivar ‘Tewangda’. The plants were incubated at 38 °C and 45 °C, and the suitable temperature for eggplant growth was used as a control. The treatment times were 3 h and 6 h. The skin of the eggplant was taken for transcriptome sequencing, qRT-PCR assays and bioinformatic analysis. The results showed that 770 genes were differentially expressed between different treatments. Gene Ontology (GO) database and Kyoto Encyclopedia of Genes and Genomes (KEGG) database analyses identified 16 genes related to anthocyanin biosynthesis, among which CHSB was upregulated. Other genes, including BHLH62, MYB380, CHI3, CHI, CCOAOMT, AN3, ACT-2, HST, 5MA-T1, CYP75A2, ANT17, RT, PAL2, and anthocyanin 5-aromatic acyltransferase were downregulated. In addition, the Myb family transcription factor PHL11 was upregulated in the CK 3 h vs 45 °C 3 h, CK 3 h vs 38 °C 3 h, and CK 6 h vs 38 °C 6 h comparisons, and the transcription factor bHLH35 was upregulated in the CK 3 h vs 38 °C 3 h and CK 6 h vs 38 °C 6 h comparisons. These results indicated that high temperature will downregulate most of the genes in the anthocyanin biosynthetic pathway of eggplant. Our data have a reference value for the heat resistance mechanism of eggplant and can provide directions for molecular breeding of heat-resistant germplasm with anthocyanin content in eggplant.

Global warming induces heat stress in eggplant, seriously affecting its quality and yield. The response to heat stress is a complex regulatory process; however, the exact mechanism in eggplant is unknown. We analyzed the transcriptome of eggplant under different high-temperature treatments using RNA-Seq technology. Three libraries treated at high temperatures were generated and sequenced. There were 40,733,667, 40,833,852, and 40,301,285 clean reads with 83.98%, 79.69%, and 84.42% of sequences mapped to the eggplant reference genome in groups exposed to 28°C (CK), 38°C (T38), and 43°C (T43), respectively. There were 3,067 and 1,456 DEGs in T38 vs CK and T43 vs CK groups, respectively. In these two DEG groups, 315 and 342 genes were up- and down-regulated, respectively, in common. Differential expression patterns of DEGs in antioxidant enzyme systems, detoxication, phytohormones, and transcription factors under heat stress were investigated. We screened heat stress-related genes for further validation by qRT-PCR. Regulation mechanisms may differ under different temperature treatments, in which heat shock proteins and heat stress transcription factors play vital roles. These results provide insight into the molecular mechanisms of the heat stress response in eggplant and may be useful in crop breeding.

Background: Fresh-cut processing promotes enzymatic browning of fresh fruits and vegetables, which negatively affects the appearance of products and impacts their nutrition. We used the RNA-Seq technique to analyze the transcriptomic changes occurring during the browning of fresh-cut eggplant (Solanum melongena L.) fruit samples from a browning-sensitive cultivar and a browning-resistant cultivar to investigate the genes and molecular mechanisms involved in browning. Results: A total of 111.55 GB of high-quality reads were generated, the genomes of each sample were compared, and 83.50%–95.14% of the data was mapped to the eggplant reference genome. Furthermore, a total of 19631 differentially expressed genes were identified, among which 12 genes and two WRKY transcription factors were identified as potentially involved in enzymatic browning in fresh-cut eggplant fruit. Moreover, the 14 differentially expressed genes associated with browning were verified using qRT-PCR. Conclusions: Several genes associated with phenolic oxidation, phenylpropanoid biosynthesis, and flavonoid biosynthesis were found to be differentially regulated between the eggplant cultivars with different browning sensitivities. This work is of great theoretical significance, as it provides a basis for future molecular studies and improvement of eggplants, and lays a theoretical foundation for the development of browning-resistant fresh-cut fruits and vegetables.

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.