Genome-Wide Identification and Expression Analysis of the SPL Gene Family in Solanum melongena (Eggplant)

The SPL (SQUAMOSA promoter-binding protein-like) transcription factor gene family plays a crucial role in the growth of plants, including fruit development. Although the SPL gene family has been widely studied in many plants, it remains unexplored in eggplant, an important Solanaceae vegetable crop. In this study, we performed a genome-wide analysis and identified 11 SmSPL genes with 10 motifs in the eggplant genome, which were assigned to five groups based on the amino acid sequences and the gene structure of the SBP domain. In addition, the expression patterns of 11 SmSPL genes were analyzed in different tissue types and at four different fruit development stages in eggplant. The results showed that all SmSPL genes were expressed differently in various tissues, suggesting that they may play different roles in the regulation of the development of different organs. Specifically, the expression level of SmSPL_5 was increased at the fruit expansion stage and showed the highest expression levels at 16 and 24 days after pollination, suggesting that it may be involved in regulating fruit development at both the fruit expansion and commercial fruit stages. Overall, this study provides an important basis for further exploring the function of the SmSPL gene family in eggplant.