Tomato Fruit Development and Metabolism

Abstract

Tomato (Solanum lycopersicum L.) belongs to the Solanaceae family and is the second most important fruit or vegetable crop next to potato (Solanum tuberosum L.). It is cultivated for fresh fruit and processed products. Tomatoes contain many health-promoting compounds including vitamins, carotenoids, and phenolic compounds. In addition to its economic and nutritional importance, tomatoes have become the model for the study of fleshy fruit development. Tomato is a climacteric fruit and dramatic metabolic changes occur during its fruit development. In this review, we provide an overview of our current understanding of tomato fruit metabolism. We begin by detailing the genetic and hormonal control of fruit development and ripening, after which we document the primary metabolism of tomato fruits, with a special focus on sugar, organic acid, and amino acid metabolism. Links between primary and secondary metabolic pathways are further highlighted by the importance of pigments, flavonoids, and volatiles for tomato fruit quality. Finally, as tomato plants are sensitive to several abiotic stresses, we briefly summarize the effects of adverse environmental conditions on tomato fruit metabolism and quality.

Keywords: Solanum lycopersicum; abiotic stress; fruit ripening; fruit set; genetic control; hormonal control; primary metabolism; secondary metabolism.

Figure 1

Genetic and hormonal control of tomato fruit development. (A) Main stages of tomato fruit development. (B) Genes involved in the control of tomato fruit development that are mentioned in this article. (C) Main hormones involved in tomato fruit development during fruit set and fruit growth (green) and fruit ripening (red). (D) Genes involved in the hormonal regulation of fruit development that are mentioned in this article. The Figure summarizes data collected by Gillaspy et al. (1993); Srivastava and Handa (2005); Karlova et al. (2014) and Obroucheva (2014).

Figure 2

Global overview of metabolic changes occurring during the transition from green expanding fruit to ripening processes (from 30 DAA to 60 DAA) in tomato fruit. Names of metabolites in red, green and black indicate increase, decrease or no changes, respectively. Metabolites are analyzed mainly in pericarps. The Figure summarizes data collected by Carrari and Fernie (2006); Gilbert (2009); Mounet et al. (2009); Centeno et al. (2011); Beauvoit et al. (2014); Biais et al. (2014), Van Meulebroek et al. (2015), Van de Poel et al. (2012), and Zhao et al. (2018).