Identification, introgression, and validation of fruit volatile QTLs from a red-fruited wild tomato species.

Volatile organic compounds (VOCs) are major determinants of fruit flavor, a primary objective in tomato breeding. A recombinant inbred line (RIL) population consisting of 169 lines derived from a cross between Solanum lycopersicum and a red-fruited wild tomato species Solanum pimpinellifolium accession (SP) was characterized for VOCs in three different seasons. Correlation and hierarchical cluster analyses were performed on the 52 VOCs identified, providing a tool for the putative assignation of individual compounds to metabolic pathways. Quantitative trait locus (QTL) analysis, based on a genetic linkage map comprising 297 single nucleotide polymorphisms (SNPs), revealed 102 QTLs (75% not described previously) corresponding to 39 different VOCs. The SP alleles exerted a positive effect on most of the underlying apocarotenoid volatile QTLs-regarded as desirable for liking tomato-indicating that alleles inherited from SP are a valuable resource for flavor breeding. An introgression line (IL) population developed from the same parental genotypes provided 12 ILs carrying a single SP introgression and covering 85 VOC QTLs, which were characterized at three locations. The results showed that almost half of the QTLs previously identified in the RILs maintained their effect in an IL form, reinforcing the value of these QTLs for flavor/aroma breeding in cultivated tomato.

Cisplatin Nephrotoxicity and Longitudinal Growth in Children With Solid Tumors: A Retrospective Cohort Study.

Cisplatin, a major antineoplastic drug used in the treatment of solid tumors, is a known nephrotoxin. This retrospective cohort study evaluated the prevalence and severity of cisplatin nephrotoxicity in 54 children and its impact on height and weight.We recorded the weight, height, serum creatinine, and electrolytes in each cisplatin cycle and after 12 months of treatment. Nephrotoxicity was graded as follows: normal renal function (Grade 0); asymptomatic electrolyte disorders, including an increase in serum creatinine, up to 1.5 times baseline value (Grade 1); need for electrolyte supplementation <3 months and/or increase in serum creatinine 1.5 to 1.9 times from baseline (Grade 2); increase in serum creatinine 2 to 2.9 times from baseline or need for electrolyte supplementation for more than 3 months after treatment completion (Grade 3); and increase in serum creatinine ≥3 times from baseline or renal replacement therapy (Grade 4).Nephrotoxicity was observed in 41 subjects (75.9%). Grade 1 nephrotoxicity was observed in 18 patients (33.3%), Grade 2 in 5 patients (9.2%), and Grade 3 in 18 patients (33.3%). None had Grade 4 nephrotoxicity. Nephrotoxicity patients were younger and received higher cisplatin dose, they also had impairment in longitudinal growth manifested as statistically significant worsening on the height Z Score at 12 months after treatment. We used a multiple logistic regression model using the delta of height Z Score (baseline-12 months) as dependent variable in order to adjust for the main confounder variables such as: germ cell tumor, cisplatin total dose, serum magnesium levels at 12 months, gender, and nephrotoxicity grade. Patients with nephrotoxicity Grade 1 where at higher risk of not growing (OR 5.1, 95% CI 1.07-24.3, P=0.04). The cisplatin total dose had a significant negative relationship with magnesium levels at 12 months (Spearman r=-0.527, P=<0.001).

A visual reporter system for virus-induced gene silencing in tomato fruit based on anthocyanin accumulation.

Virus-induced gene silencing (VIGS) is a powerful tool for reverse genetics in tomato (Solanum lycopersicum). However, the irregular distribution of the effects of VIGS hampers the identification and quantification of nonvisual phenotypes. To overcome this limitation, a visually traceable VIGS system was developed for fruit, comprising two elements: (1) a transgenic tomato line (Del/Ros1) expressing Antirrhinum majus Delila and Rosea1 transcription factors under the control of the fruit-specific E8 promoter, showing a purple-fruited, anthocyanin-rich phenotype; and (2) a modified tobacco rattle virus VIGS vector incorporating partial Rosea1 and Delila sequences, which was shown to restore the red-fruited phenotype upon agroinjection in Del/Ros1 plants. Dissection of silenced areas for subsequent chemometric analysis successfully identified the relevant metabolites underlying gene function for three tomato genes, phytoene desaturase, TomloxC, and SlODO1, used for proof of concept. The C-6 aldehydes derived from lipid 13-hydroperoxidation were found to be the volatile compounds most severely affected by TomloxC silencing, whereas geranial and 6-methyl-5-hepten-2-one were identified as the volatiles most severely reduced by phytoene desaturase silencing in ripening fruit. In a third example, silencing of SlODO1, a tomato homolog of the ODORANT1 gene encoding a myb transcription factor, which regulates benzenoid metabolism in petunia (Petunia hybrida) flowers, resulted in a sharp accumulation of benzaldehyde in tomato fruit. Together, these results indicate that fruit VIGS, enhanced by anthocyanin monitoring, can be a powerful tool for reverse genetics in the study of the metabolic networks operating during fruit ripening.

Metabolic characterization of loci affecting sensory attributes in tomato allows an assessment of the influence of the levels of primary metabolites and volatile organic contents.

Numerous studies have revealed the extent of genetic and phenotypic variation between both species and cultivars of tomato. Using a series of tomato lines resulting from crosses between a cherry tomato and three independent large fruit cultivar (Levovil, VilB, and VilD), extensive profiling of both central primary metabolism and volatile organic components of the fruit was performed. In this study, it was possible to define a number of quantitative trait loci (QTLs) which determined the levels of primary metabolites and/or volatile organic components and to evaluate their co-location with previously defined organoleptic QTLs. Correlation analyses between either the primary metabolites or the volatile organic compounds and organoleptic properties revealed a number of interesting associations, including pharmaceutical aroma-guaiacol and sourness-alanine, across the data set. Considerable correlation within the levels of primary metabolites or volatile organic compounds, respectively, were also observed. However, there was relatively little association between the levels of primary metabolites and volatile organic compounds, implying that they are not tightly linked to one another. A notable exception to this was the strong association between the levels of sucrose and those of a number of volatile organic compounds. The combined data presented here are thus discussed both with respect to those obtained recently from wide interspecific crosses of tomato and within the framework of current understanding of the chemical basis of fruit taste.