QTL analysis of fruit quality in fresh market tomato: a few chromosome regions control the variation of sensory and instrumental traits

Abstract

The organoleptic quality of tomato fruit involves a set of attributes (flavour, aroma, texture) that can be evaluated either by sensory analyses or by instrumental measures. In order to study the genetic control of this characteristic, a recombinant inbred line (RIL) population was developed from an intraspecific cross between a cherry tomato line with a good overall aroma intensity and an inbred line with medium flavour but bigger fruits. A total of 38 traits involved in organoleptic quality were evaluated. Physical traits included fruit weight, diameter, colour, firmness, and elasticity. Chemical traits were dry matter weight, titratable acidity, pH, and the contents of soluble solids, sugars, lycopene, carotene, and 12 aroma volatiles. A panel of trained assessors quantified sensory attributes: flavour (sweetness and sourness), aroma (overall aroma intensity, together with candy, lemon, citrus fruit, and pharmaceutical aromas) and texture (firmness, meltiness, mealiness, juiciness, and skin difficult to swallow). RILs showed a large range of variation. Molecular markers were used to map a total of 130 quantitative trait loci (QTL) for the 38 traits. They were mainly distributed in a few chromosome regions. Major QTLs (R(2) >30%) were detected for fruit weight, diameter, colour, firmness, meltiness, and for six aroma volatiles. The relationships between instrumental measures and sensory traits were analysed with regard to the QTL map. A special insight was provided about the few regions where QTLs are related to multiple traits. A few examples are shown to illustrate how the simultaneous analysis of QTL segregation for related traits may aid in understanding the genetic control of quality traits and pave the way towards QTL characterization.

Genome-Wide Association in Tomato Reveals 44 Candidate Loci for Fruit Metabolic Traits

“…In tomato, chromosome 2 was suggested to be interesting, as it carries a lot of QTLs for traits of interest such as fresh weight (fw2.2; Frary et al, 2000), fruit morphology (Causse et al, 2002), and locule number (lcn2.1; Muños et al, 2011), to name a few (Ranc et al, 2012;Xu et al, 2013), supporting the identification of numerous associations on this chromosome in our study.…”

“…Over the last two decades, numerous QTLs have been identified for traits such as fresh weight using linkage approaches (Frary et al, 2000;Zhang et al, 2012;Chakrabarti et al, 2013) but also for other fruit-related traits such as fruit ascorbic acid levels (Stevens et al, 2007), sensory and instrumental quality traits (Causse et al, 2002), sugar and organic acids (Fulton et al, 2002), and metabolic components (Schauer et al, 2008). Large tomato germplasm collections have been characterized at the molecular level using simple sequence repeat (Ranc et al, 2008) and single-nucleotide polymorphism (SNP) markers (Blanca et al, 2012;Shirasawa et al, 2013), giving insights into population structure, tomato evolutionary history, and the genetic architecture of traits of agronomic interest.…”

Increase in Tomato Locule Number Is Controlled by Two Single-Nucleotide Polymorphisms Located NearWUSCHEL

“…Our study exploited a recombinant inbred line population obtained from an intraspecific cross between two cultivated tomato accessions (Causse et al, 2002), Cervil, a cherry tomato line, and Levovil, a classical French fresh market line carrying round fruits with many locules weighing approximately 100 g. The QTL was initially mapped to the TG463 region (Lecomte et al, 2004) using two near-isogenic lines (CF12-C and CF13-L) that were genetically identical except for a 30-centiMorgan (cM) region containing lc. CF12-C contains the low-locule-number allele from Cervil, and CF13-L contains the high-locule-number allele from Levovil (Fig.…”

“…The z100_CAPS and z274 primers were used to amplify the T1555 and TG191 markers, and the resulting PCR products were digested with BamHI and NdeI, respectively, and mapped on the F6 recombinant inbred line population derived from the cross between Cervil and Levovil (Causse et al, 2002). Taqman markers developed from the associated SNPs were used to screen 2,688 F2 plants for the fine-mapping analysis.…”

A Role for Differential Glycoconjugation in the Emission of Phenylpropanoid Volatiles from Tomato Fruit Discovered Using a Metabolic Data Fusion Approach

“…MeSA content has been shown to be negatively correlated with typical tomato flavor (Krumbein and Auerswald, 1998). Guaiacol is also a well-known flavoring compound and has been associated with a so-called "pharmaceutical" aroma in tomato fruits (Causse et al, 2002). Likewise, eugenol is a well-known odorant that gives the distinctive, pungent flavor to cloves (Syzygium aromaticum) and significantly contributes to the aroma of cinnamon (Cinnamomum verum).…”