Fruit metabolic and transcriptional programs differentiate among Andean tomato (Solanum lycopersicum L.) accessions.

MAIN CONCLUSION: Andean tomatoes differed from the wild ancestor in the metabolic composition and the expression of genes related with mitochondrial functions, and environmental stresses, making them potentially suitable for breeding programmes. Traditional landraces or "criollo" tomatoes (Solanum lycopersicum L.) from Andean areas of Argentina, selected for their fruit quality, were analysed in this study. We explored the metabolome and transcriptome of the ripe fruit in nine landrace accessions representing the seven genetic groups and compared them to the mature fruit of the wild progenitor Solanum pimpinellifolium. The content of branched- (isoleucine and valine) and aromatic (phenylalanine and tryptophan) amino acids, citrate and sugars were significantly different in the fruit of several "criollo" tomatoes compared to S. pimpinellifolium. The transcriptomic profile of the ripe fruit showed several genes significantly and highly regulated in all varieties compared to S. pimpinellifolium, like genes encoding histones and mitochondrial proteins. Additionally, network analysis including transcripts and metabolites identified major hubs with the largest number of connections such as constitutive photomorphogenic protein 1 (a RING finger-type ubiquitin E3 ligase), five Zn finger transcription factors, ascorbate peroxidase, acetolactate synthase, and sucrose non-fermenting 1 kinase. Co-expression analysis of these genes revealed a potential function in acquiring tomato fruit quality during domestication.

Contrasting metabolic profiles of tasty Andean varieties of tomato fruit in comparison with commercial ones.

BACKGROUND: The fruits of most commercial tomato cultivars (Solanum lycopersicum L.) are deficient in flavour. In contrast, traditional 'criollo' tomato varieties are appreciated for fruit of excellent organoleptic quality. Small farmers from the Andean valleys in Argentina have maintained their own tomato varieties, which were selected mainly for flavour. This work aims to correlate the chemical composition of the fruit with the sensory attributes of eight heirloom tomato varieties. The long-term goal is to identify potential candidate genes capable of altering the chemicals involved in flavour. RESULTS: A sensory analysis was conducted and the metabolomics of fruit were determined. The data revealed that defined tomato aroma and sourness correlated with citrate and several volatile organic compounds (VOC), such as α-terpineol, p-menth-1-en-9-al, linalool and 3,6-dimethyl-2,3,3a,4,5,7a-hexahydrobenzofuran (DMHEX), a novel volatile recently identified in tomato. Two sensory attributes - sweetness and a not-acidic taste - correlated with the characteristic tomato taste, and also with fructose, glucose, and two VOCs, benzaldehyde, and 2-methyl-2-octen-4-one. CONCLUSIONS: These data provide new evidence of the complex chemical combination that induced the flavour and aroma of the good-tasting 'criollo' tomato fruit. That is, the compounds that correlated with defined tomato aroma and acidic taste did not correlate with sweetness, or with characteristic tomato taste. © 2018 Society of Chemical Industry.

Assessment and characterization of tomato lipophilic electrophiles and their potential contribution to nutraceutical properties via SKN-1/Nrf2 signaling activation.

Phytochemical electrophiles are drawing significant attention due to their properties to modulate signaling pathways related to cellular homeostasis. The aim of this study was to develop new tools to examine the electrophilic activity in food and predict their beneficial effects on health. We developed a spectrophotometric assay based on the nitrobenzenethiol (NBT) reactivity, as a thiol-reactive nucleophile, to screen electrophiles in tomato fruits. The method is robust, simple, inexpensive, and could be applied to other types of food. We quantified the electrophile activity in a tomato collection and associated this activity with the pigment composition. Thus, we identified lycopene, ß- and γ-carotenes, 16 by-products of carotenoid oxidation and 18 unknown compounds as NBT-reactive by HPLC-MS/MS. The potential benefits of NBT-reactive compounds on health were evaluated in the in vivo model of C. elegans where they activated the SKN-1/Nrf2 pathway, evidencing the ability of electrophilic compounds to induce a biological response.

Heritability and expected selection response for yield traits in blanched asparagus.

Despite the continuous breeding that has been conducted with asparagus (Asparagus officinalis L.) since the beginning of the last century, there is little information on parameters for predicting direct and indirect selection response. Yield traits for blanched asparagus production were studied along a two-year period in a half-sib family population planted in Zavalla, Argentina. Half-sib family mean heritability values were low for total yield and marketable spear number (0.31 and 0.35), intermediate for marketable yield and total spear number (0.55 and 0.64), and relatively high for spear diameter and spear weight (0.75 and 0.74). An average increase in marketable yield of 15.9% is expected after each cycle of selection of the top 5% of the families. Total yield failed to express significant genetic correlations with any of the yield components; meanwhile marketable yield showed highly significant relations with market spear number (0.96) and spear weight (0.89). Indirect selection response over yield components (CRx) failed to be advantageous over direct selection (Rx), since the ratio CRx/Rx was always equal or below unity.