The Genetic Basis of Tomato Aroma

Abstract

Tomato (Solanum lycopersicum L.) aroma is determined by the interaction of volatile compounds (VOCs) released by the tomato fruits with receptors in the nose, leading to a sensorial impression, such as “sweet”, “smoky”, or “fruity” aroma. Of the more than 400 VOCs released by tomato fruits, 21 have been reported as main contributors to the perceived tomato aroma. These VOCs can be grouped in five clusters, according to their biosynthetic origins. In the last decades, a vast array of scientific studies has investigated the genetic component of tomato aroma in modern tomato cultivars and their relatives. In this paper we aim to collect, compare, integrate and summarize the available literature on flavour-related QTLs in tomato. Three hundred and 5ifty nine (359) QTLs associated with tomato fruit VOCs were physically mapped on the genome and investigated for the presence of potential candidate genes. This review makes it possible to (i) pinpoint potential donors described in literature for specific traits, (ii) highlight important QTL regions by combining information from different populations, and (iii) pinpoint potential candidate genes. This overview aims to be a valuable resource for researchers aiming to elucidate the genetics underlying tomato flavour and for breeders who aim to improve tomato aroma.

Breeding Tomato Hybrids for Flavour: Comparison of GWAS Results Obtained on Lines and F1 Hybrids

“…We defined overlaps as associations for traits belonging to the same metabolic pathway, and which CIs partially overlapped, or were separated by less than 0.1 Mpb. CGs identified in the CCI, TCI and TCT associations were then further compared with those suggested in a review from [ 20 ] which encompassed QTLs reported for aroma from 16 studies performed on GWAS panels or biparental segregating populations.…”

“…Introgression Lines (ILs) derived from crosses between domesticated tomato ( Solanum lycopersicum ) and the wild species Solanum pennellii concomitantly enabled the cloning of major genes regulating key VOC synthesis [ 18 , 19 ]. Other tomato wild relatives such as Solanum Pimpinellifolium or Solanum Habrochaites have also been studied through biparental segregating populations and provided new QTLs for flavour-related traits as reviewed in [ 20 ]. Precise QTL mapping allowed by genome-wide association studies (GWAS) later brought better resolution around QTLs, with the dissection of previously identified large genomic regions into many single QTLs, which provided easier identification of candidate genes (‘CGs’) [ 21 , 22 , 23 ].…”

“…Although tremendous improvement has been achieved for QTL identification on homozygous plant material [ 20 ], breeders still need insight into the flavour improvement they can expect from these QTLs in their F1 hybrids, as no study has yet been undertaken on the evolution of flavour-related traits within heterozygous plant material. In the European Union, 89% of registered tomato varieties were hybrids in 2018 [ 24 ].…”

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

“…Tomato is one of the most important vegetables worldwide. Recent breeding strategies have focused not only producer-favorable traits such as high yield, long shelf life, and disease resistance, but also on flavor [ 1 ]. The major flavors of tomato are the result of interactions between taste and aroma [ 2 ].…”

Natural Genetic Diversity in Tomato Flavor Genes

“…The major biochemical pathways involved in metabolite production and accumulation in tomato have been partially elucidated in recent years (Klee and Tieman, 2018;Martina et al, 2021). The key underlying genes in these pathways were often identified using introgression lines, relying on interspecific variation between cultivated tomato and the distantly related green-fruited Solanum pennellii (Fridman et al, 2004;Goulet et al, 2012Goulet et al, , 2015.…”