The dissection of tomato flavor: biochemistry, genetics, and omics

Abstract

Flavor and quality are the major drivers of fruit consumption in the US. However, the poor flavor of modern commercial tomato varieties is a major cause of consumer dissatisfaction. Studies in flavor research have informed the role of volatile organic compounds in improving overall liking and sweetness of tomatoes. These studies have utilized and applied the tools of molecular biology, genetics, biochemistry, omics, machine learning, and gene editing to elucidate the compounds and biochemical pathways essential for good tasting fruit. Here, we discuss the progress in identifying the biosynthetic pathways and chemical modifications of important tomato volatile compounds. We also summarize the advances in developing highly flavorful tomato varieties and future steps toward developing a “perfect tomato”.

The Crucial Role of SlGSNOR in Regulating Postharvest Tomato Fruit Ripening

“…It has been found that phenolic acids and flavonoids are essential compounds for sustaining great quality in postharvest fruit [ 27 ]. Also, they are a crucial source for tomato flavor construction [ 42 ]. In Inonotus obliquus , both higher cellular NO content and GSNOR inhibition could raise polyphenol production, illustrating the role of NO and GSNOR in phenol biosynthesis [ 43 ].…”

A metabolome and transcriptome survey to tap the dynamics of fruit prolonged shelf-life and improved quality within Greek tomato germplasm

“…On the other hand, in LSL, the accumulation of both leucine as well as the nitrogen- and sulfur-containing compounds 2-isobuthylthiazole (wasabi, leafy odor) and 3-methylbutanenitrile (pungent) were induced, suggesting that the pathway is stimulated towards the production of these compounds. These leucine-derived compounds are very abundant in tomato fruit, being synthesized by the conjugation of 3-methylbutanal with cysteine ( Liscombe et al., 2022 ; Kaur et al., 2023 ). However, the underlying key gene, tetrahydrothiazolidine N-hydroxylase ( Wang et al., 2023 ), was not differentially expressed between genotypes, suggesting that other factors may also be important.…”

“…However, the underlying key gene, tetrahydrothiazolidine N-hydroxylase ( Wang et al., 2023 ), was not differentially expressed between genotypes, suggesting that other factors may also be important. All the above-mentioned BCAA-derived compounds, found in either of the two genotypes, have been associated with liking by consumers ( Kaur et al., 2023 ).…”

“…Along with these important phytonutrients that are appreciated by consumers, tomato flavor greatly affects consumer acceptance and preferences, re-directing breeders’ goal from yield-oriented towards nutritional- and flavor-oriented strategies, regenerating the necessity of exploring the genetics underlying tomato flavor ( Wang et al., 2023 ). Tomato’s unique flavor arises from the balance between sugars (glucose and fructose), acids (citrate, malate, ascorbate and glutamate) and volatile organic compounds (VOCs), constituting of a huge heterogeneous group of diverse molecules ( Colantonio et al., 2022 ; Kaur et al., 2023 ). The loss of positive contributors to fruit aroma has been previously associated to linkage drag with other commercial traits such as fruit weight and disease resistance ( Li et al., 2022a ).…”

Volatilomics-Based Discovery of Key Volatiles Affecting Flavor Quality in Tomato

“…The following key volatiles affect the nutritional quality of tomato fruits and have been associated with particular aromas favored by consumers: 2-phenylacetaldehyde (floral), 3-methylbutanol (malt), 6-methyl-5-hepten-2-one (fruity and floral), and hexanal (grassy). A number of other volatiles are known to underlie aromatic, sour, and sweet flavors in tomato fruits [ 6 , 7 ]. Organic volatiles account for 62% of the sweet and 22% of the sour flavors of tomato fruits [ 8 ].…”