Abstract
Sweetness and acidity determine fruit taste, and their good balance is important for fruit quality. Although fruits accumulate organic acids at high concentrations in vacuoles, transporters responsible for organic acids accumulation into vacuoles have not yet been identified. In this study, we analyzed the functions of SltDT1, the homolog of AttDT (Arabidopsis thaliana tonoplast dicarboxilate transporter), to examine whether SltDT1 is involved in organic acids accumulation in fruits. SltDT1-GFP fusion protein localized in the vacuolar membrane, when it was expressed in onion epidermal cells. Expression analysis by quantitative RT-PCR revealed that SltDT1 is expressed constitutively in the whole tomato plant. Since AttDT does not have paralogs, SltDT1 might be the only one or the main working ortholog of AttDT in tomato and might play important roles in tomato fruits. We have generated transgenic tomato plants overexpressing SltDT1 under the control of the fruit-specific 2A11 promoter. We will present the data concerning fruit characters of the transgenic tomato.
