Seeded and Parthenocarpic Cherry Tomato Fruits Exhibit Similar Sucrose, Glucose, and Fructose Levels, Despite Dissimilarities in UGPase and SPS Gene Expression and Enzyme Activity

Farmers often resort to the production of auxin-induced parthenocarpic tomato fruits to overcome the adverse climatic conditions which are unfavorable for sufficient fertilization and to lengthen the production period. Even though this practice improves the out-of-season yield, it often undermines fruit quality. In the current study, we examined the effect of induced parthenocarpy in cherry tomato cv. Conchita on the concentration of the main sugars, and on the expression, the activity and the localization of UDP-glucose pyrophosphorylase (UGPase) and sucrose phosphate synthase (SPS), enzymes that are actively involved in sucrose metabolism. Minor differences were detected in sugar levels of seeded and parthenocarpic fruits, whereas considerable variances were found in transcript accumulation and enzyme activities of both UGPase and SPS. Moreover, both proteins were present in the developing seeds. Our data indicate that although induced parthenocarpy significantly influences sucrose metabolism, it has a negligible effect on sugar levels.