Correction: Structural variation underlies functional diversity at methyl salicylate loci in tomato.

[This corrects the article DOI: 10.1371/journal.pgen.

Variation in ripe fruit volatiles across the tomato clade: An evolutionary framework for studying fruit scent diversity in a crop wild relative.

Premise: The scents of volatile organic compounds (VOCs) are an important component of ripe fleshy fruit attractiveness, yet their variation across closely related wild species is poorly understood. Phylogenetic patterns in these compounds and their biosynthetic pathways offer insight into the evolutionary drivers of fruit diversity, including whether scent can communicate an honest signal of nutrient content to animal dispersers. We assessed ripe fruit VOC content across the tomato clade (Solanum sect.

Machine learning applications to improve flavor and nutritional content of horticultural crops through breeding and genetics.

Over the last decades, significant strides were made in understanding the biochemical factors influencing the nutritional content and flavor profile of fruits and vegetables. Product differentiation in the produce aisle is the natural consequence of increasing consumer power in the food industry. Cotton-candy grapes, specialty tomatoes, and pineapple-flavored white strawberries provide a few examples.

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

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.

Natural variations in the Sl-AKR9 aldo/keto reductase gene impact fruit flavor volatile and sugar contents.

The unique flavors of different fruits depend upon complex blends of soluble sugars, organic acids, and volatile organic compounds. 2-Phenylethanol and phenylacetaldehyde are major contributors to flavor in many foods, including tomato. In the tomato fruit, glucose, and fructose are the chemicals that most positively contribute to human flavor preferences.

Structural variation underlies functional diversity at methyl salicylate loci in tomato.

Methyl salicylate is an important inter- and intra-plant signaling molecule, but is deemed undesirable by humans when it accumulates to high levels in ripe fruits. Balancing the tradeoff between consumer satisfaction and overall plant health is challenging as the mechanisms regulating volatile levels have not yet been fully elucidated. In this study, we investigated the accumulation of methyl salicylate in ripe fruits of tomatoes that belong to the red-fruited clade.

Postharvest chilling diminishes melon flavor effects on volatile acetate ester biosynthesis.

In postharvest handling systems, refrigeration can extend fruit shelf life and delay decay slowing ripening progress; however, it selectively alters the biosynthesis of flavor-associated volatile organic compounds (VOCs), which results in reduced flavor quality. Volatile esters are major contributors to melon fruit flavor. The more esters, the more consumers enjoy the melon fruit.

A family of methyl esterases converts methyl salicylate to salicylic acid in ripening tomato fruit.

Methyl salicylate imparts a potent flavor and aroma described as medicinal and wintergreen that is undesirable in tomato (Solanum lycopersicum) fruit. Plants control the quantities of methyl salicylate through a variety of biosynthetic pathways, including the methylation of salicylic acid to form methyl salicylate and subsequent glycosylation to prevent methyl salicylate emission. Here, we identified a subclade of tomato methyl esterases, SALICYLIC ACID METHYL ESTERASE1-4, responsible for demethylation of methyl salicylate to form salicylic acid in fruits.

Terpene volatiles mediates the chemical basis of blueberry aroma and consumer acceptability.

Flavor is among the most important traits valued by consumers of fresh fruits. Human perception of flavor occurs primarily through two main sensory inputs, taste and aroma. Through retronasal olfaction, volatile organic compounds (VOCs) emitted by the fruit are able to produce the sensation of aroma which when combined with gustatory inputs from the tongue together underly our perception of the thousands of flavors we experience throughout our lives.

Branched-Chain Volatiles in Fruit: A Molecular Perspective.

Branched-chain volatiles (BCVs) constitute an important family of fruit volatile metabolites essential to the characteristic flavor and aroma profiles of many edible fruits. Yet in contrast to other groups of volatile organic compounds important to fruit flavor such as terpenoids, phenylpropanoids, and oxylipins, the molecular biology underlying BCV biosynthesis remains poorly understood. This lack of knowledge is a barrier to efforts aimed at obtaining a more comprehensive understanding of fruit flavor and aroma and the biology underlying these complex phenomena.

A flavin-dependent monooxygenase produces nitrogenous tomato aroma volatiles using cysteine as a nitrogen source.

Tomato () produces a wide range of volatile chemicals during fruit ripening, generating a distinct aroma and contributing to the overall flavor. Among these volatiles are several aromatic and aliphatic nitrogen-containing compounds for which the biosynthetic pathways are not known. While nitrogenous volatiles are abundant in tomato fruit, their content in fruits of the closely related species of the tomato clade is highly variable.

Metabolomic selection for enhanced fruit flavor.

Although they are staple foods in cuisines globally, many commercial fruit varieties have become progressively less flavorful over time. Due to the cost and difficulty associated with flavor phenotyping, breeding programs have long been challenged in selecting for this complex trait. To address this issue, we leveraged targeted metabolomics of diverse tomato and blueberry accessions and their corresponding consumer panel ratings to create statistical and machine learning models that can predict sensory perceptions of fruit flavor.

High-Throughput Chlorophyll and Carotenoid Profiling Reveals Positive Associations with Sugar and Apocarotenoid Volatile Content in Fruits of Tomato Varieties in Modern and Wild Accessions.

Flavor and nutritional quality has been negatively impacted during the course of domestication and improvement of the cultivated tomato ( ). Recent emphasis on consumers has emphasized breeding strategies that focus on flavor-associated chemicals, including sugars, acids, and aroma compounds. Carotenoids indirectly affect flavor as precursors of aroma compounds, while chlorophylls contribute to sugar production through photosynthesis.

Natural Genetic Diversity in Tomato Flavor Genes.

Fruit flavor is defined as the perception of the food by the olfactory and gustatory systems, and is one of the main determinants of fruit quality. Tomato flavor is largely determined by the balance of sugars, acids and volatile compounds. Several genes controlling the levels of these metabolites in tomato fruit have been cloned, including , , , , and .

Identification of a lipase gene with a role in tomato fruit short-chain fatty acid-derived flavor volatiles by genome-wide association.

Fatty acid-derived volatile organic compounds (FA-VOCs) make significant contributions to tomato (Solanum lycopersicum) fruit flavor and human preferences. Short-chain FA-VOCs (C5 and C6) are among the most abundant and important volatile compounds in tomato fruits. The precursors of these volatiles, linoleic acid (18:2) and linolenic acid (18:3), are derived from cleavage of glycerolipids.

Major Impacts of Widespread Structural Variation on Gene Expression and Crop Improvement in Tomato.

Structural variants (SVs) underlie important crop improvement and domestication traits. However, resolving the extent, diversity, and quantitative impact of SVs has been challenging. We used long-read nanopore sequencing to capture 238,490 SVs in 100 diverse tomato lines.

A Review of the Fruit Volatiles Found in Blueberry and Other Species.

Variations in volatile organic compound (VOC) type and content can result in noticeable differences in fruit aroma. The genus encompasses over 500 distinct species of berry-producing plants, several of which are important to commercial horticulture. Understanding which VOCs are produced by different members of this genus could greatly aid efforts to improve the aroma of multiple crops by breeding for desirable fruit volatiles.

Genomic Evidence for Complex Domestication History of the Cultivated Tomato in Latin America.

The process of plant domestication is often protracted, involving underexplored intermediate stages with important implications for the evolutionary trajectories of domestication traits. Previously, tomato domestication history has been thought to involve two major transitions: one from wild Solanum pimpinellifolium L. to a semidomesticated intermediate, S.

The tomato pan-genome uncovers new genes and a rare allele regulating fruit flavor.

Modern tomatoes have narrow genetic diversity limiting their improvement potential. We present a tomato pan-genome constructed using genome sequences of 725 phylogenetically and geographically representative accessions, revealing 4,873 genes absent from the reference genome. Presence/absence variation analyses reveal substantial gene loss and intense negative selection of genes and promoters during tomato domestication and improvement.

Meta-analysis of genome-wide association studies provides insights into genetic control of tomato flavor.

Tomato flavor has changed over the course of long-term domestication and intensive breeding. To understand the genetic control of flavor, we report the meta-analysis of genome-wide association studies (GWAS) using 775 tomato accessions and 2,316,117 SNPs from three GWAS panels. We discover 305 significant associations for the contents of sugars, acids, amino acids, and flavor-related volatiles.

Quantitative Trait Loci Analysis Identifies a Prominent Gene Involved in the Production of Fatty Acid-Derived Flavor Volatiles in Tomato.

To gain insight into the genetic regulation of lipid metabolism in tomato, we conducted metabolic trait loci (mQTL) analysis following the lipidomic profiling of fruit pericarp and leaf tissue of the Solanum pennellii introgression lines (IL). To enhance mapping resolution for selected fruit-specific mQTL, we profiled the lipids in a subset of independently derived S. pennellii backcross inbred lines, as well as in a near-isogenic sub-IL population.

A Comparison of the Effects of and on Plant-Aphid Interactions.

The mutation in tomato (), which disrupts function of FATTY ACID DESATURASE 7 (FAD7), confers resistance to the potato aphid () and modifies the plant’s C6 volatile profiles. To investigate whether C6 volatiles play a role in resistance, (), which encodes a critical enzyme in C6 volatile synthesis, was silenced in wild-type tomato plants and mutants. Silencing in wild-type tomato increased potato aphid host preference and reproduction on 5-week old plants but had no influence on 3-week old plants.

The genetics of fruit flavour preferences.

Intensively bred fruit crops, including tomatoes and strawberries, are widely viewed as lacking flavour. The lack of breeder focus on the consumer is largely due to the genetic complexity of the flavour phenotype as well as a lack of a simple assay that can define consumer preferences. Rapid advances in genomics have opened up new opportunities to understand the chemistry and genetics of flavour.

Transcriptional control of strawberry ripening - two to tango.

This article comments on: 2017. The fruit-specific transcription factor FaDOF2 regulates the production of eugenol in ripe fruit receptacles. Journal of Experimental Botany 4529–4543.