Comparative transcriptomic analysis of early fruit development in eggplant (Solanum melongena L.) and functional characterization of SmOVATE5

Key messageComparative transcriptome analysis of early fruits of long and round eggplants, SmOVATE5, is involved in regulating fruit development.Eggplant, a solanaceous crop that has undergone a long period of domestication, is one of the most important vegetables worldwide. The shape of its fruit is an important agronomic trait and consumers in different regions have different preferences. However, a limited understanding of the molecular mechanisms regulating fruit development and shape has hindered eggplant breeding. In this study, we performed morphological observations and transcriptome analysis of long- and round-fruited eggplant genotypes to understand the molecular regulation during the early development of different fruit shapes. Morphological studies revealed that the two varieties already exhibited distinctly different phenotypes at the initial stage of fruit development before flowering, with rapid fruit enlargement beginning on the sixth day after flowering. Comparative transcriptome analysis identified phytohormone-related genes that were significantly upregulated on the day of flowering, indicating they may be involved in regulating the initial stages of fruit development. Notably, SmARF1 showed a sustained upregulation pattern in both varieties, suggesting that it may promote eggplant fruit growth. In addition, several differentially expressed genes of the SUN, YABBY, and OVATE families are potentially involved in the regulation of fruit development or fruit shape. We demonstrated that the SmOVATE5 gene has a negative regulatory function suppressing plant growth and development. In conclusion, this study provides new insights into the molecular regulatory mechanisms of eggplant fruit development, and the genes identified may provide valuable references for different fruit shape breeding programs.

Automated summary

This study investigated the molecular regulatory mechanisms of early fruit development in long and round eggplants through morphological observations and transcriptome analysis. The results revealed distinct phenotypic differences between the two varieties at the initial stage of fruit development before flowering, with rapid fruit enlargement starting on the sixth day after flowering. Transcriptome analysis identified upregulated phytohormone-related genes on the day of flowering, suggesting their involvement in regulating early fruit growth. Additionally, several differentially expressed genes of the SUN, YABBY, and OVATE families were potentially involved in fruit development or shape regulation. Overall, this study provides new insights into the molecular regulatory mechanisms of eggplant fruit development and identifies genes that may be valuable for various fruit shape breeding programs.