SlACO1 and SlGARP Regulate Hormone-Mediated Metabolic Profiles in Tomato Fruit

Fruit quality is determined by multiple metabolites, which are mainly affected by plant hormones. In this study, two genes, ethylene-related gene <i>SlACO1</i> and gibberellin-related gene <i>SlGARP</i>, were overexpressed (OE) and knocked down through RNAi in tomato, and the profiles of carotenoids, flavonoids, volatiles, and hormones were detected in the leaves and fruit. The color index significantly increased in <i>SlACO1</i>-OE fruit but significantly decreased in the <i>SlACO1</i>-RNAi line. Similarly, total carotenoids, volatiles, salicylic acid, and ethylene significantly increased in the fruits of <i>SlACO1</i>-OE and <i>SlGARP</i>-OE, whereas ABA decreased significantly. Some compounds, such as lycopene, 3-hexenal, and <i>d</i>-limonene, significantly increased in the fruit of <i>SlACO1</i>-OE but decreased in the <i>SlACO1</i>-RNAi line, indicating that <i>SlACO1</i> might play an important role in the accumulation of these compounds. The functional characterization of SlACO1 and SlGARP would facilitate the improvement in tomato fruit quality.