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Selenium (Se) enrichment of plants seems effective in enhancing the health-related properties of produce and in delaying plant senescence and fruit ripening. The current study investigated the effects of Se on tomato fruit ripening. Tomato (Solanum lycopersicum L.) plants were grown in hydroponics with different Se-enriched nutrient solutions. Se, as sodium selenate, was added at a rate of 0?mg?L?1 (control), 1, and 1.5?mg?L?1. Results Selenium was absorbed by roots and translocated to leaves and fruit. Enrichment with Se did not significantly affect the qualitative parameters of fruit at commercial harvest; instead it delayed ripening by affecting specific ripening-related processes (respiration, ethylene production, color evolution) during postharvest. In the current experiment 100?g of tomato hydroponically grown with a 1.5?mg Se L?1 enriched solution provided a total of 23.7?µg Se. Selenium recommended daily intake is 60?µg for women and 70?µg for men; thus the daily consumption of 100?g of enriched tomato would not lead to Se toxicity but would provide a good Se diet supplementation. Conclusions The cultivation of tomato plants in a Se-enriched solution appeared effective in producing tomato fruit with improved performance during storage and postharvest shelf life, and also with greater potential health-promoting properties. ? 2018 Society of Chemical Industry

An RNAseq study of early fruit development and stone development in plum, Prunus domestica, was mined to identify sets of genes that could be used to normalize expression studies in early fruit development. The expression values of genes previously identified from Prunus as reference genes were first extracted and found to vary considerably in endocarp tissue relative to whole fruit tissue. Nine other genes were chosen that varied less than 2-fold amongst the 20 RNAseq libraries of early fruit development and endocarp tissues. These gene were tested on a series of developmental plum fruit samples to determine if any could be used as a reference gene in the analyses of fruit-based tissues in plum. The three most stable genes as determined using RefFinder were IPGD (imidazole glycerol-phosphate dehydratase), HAM1 (histone acetyltransferase) and SNX1 (sorting nexin 1). These were further tested to analyze genes expressed differentially in endocarp tissue between normal and minimal endocarp cultivars. To determine the universality of those nine genes as fruit development reference genes, three other data sets of RNAseq from peach and apple were analyzed to determine the reference gene expression. Multiple genes exhibited tissue specific patterns of expression while one gene, the SNX1, emerged as possessing a universal pattern between the Rosaceae species, at all developmental stages, and tissue types tested. The results suggest that the use of existing RNAseq data to identify standard genes can provide stable reference genes for a specific tissues or experimental conditions under exploration.

Strawberry shelf life is limited, and little is known about the postharvest regulation of senescence in different fruit tissues. Strawberry is classified as a non-climacteric fruit, yet it is known that ethylene affects strawberry ripening. Here the effects of continuous exogenous ethylene (50 µl l−1) were investigated in cold stored strawberry (5°C). The physiological and biochemical responses of ripe strawberry were evaluated across 6 days, together with hormonal profiles of the whole fruit and individual tissues (achenes and receptacle). Continuous exposure to ethylene induced as a first response an accumulation of abscisic acid (ABA) in the receptacle tissue, followed by an increase in CO2 production. Ethylene also elicited sucrose hydrolysis and malic acid catabolism, with the major effect seen after 4 days of ethylene exposure. Additionally, accumulation of phenolics (epicatechin and chlorogenic acid) were also observed in ethylene treated strawberry. Achenes did not exhibit a response to ethylene, yet catabolism of both ABA and auxins increased by two thirds during air storage. In contrast, ethylene induced ABA accumulation in the receptacle tissue without ABA catabolism being affected. This hormonal disequilibrium in response to ethylene between the two tissues was maintained during storage, and therefore might be the precursor for the following biochemical variations reported during storage.

The effect of continuous ethylene supplementation (50 µL L-1) on cold-stored strawberry fruit physiology and biochemistry, including phytohormone (abscisic acid) metabolism was investigated. In comparison with control fruit which exhibited high sucrose and malic acid contents during storage, ethylene-treated fruits showed increased respiration, sucrose hydrolysis and concomitant reducing sugars accumulation. Ethylene supplementation did not have any effect on phenolic profile. ABA biosynthesis, in both flesh and achenes, was promoted by ethylene. The results herein suggest that controlling ethylene after harvest could suppress senescence and extend shelf-life.

Highlights • Continuous ethylene activates ACO transcription and respiration in potatoes. • 1-MCP completely inhibits the respiratory rise induced by continuous ethylene exposure. • Exogenous ethylene promptly activates parenchymatic ABA catabolism via CYP707A upregulation. • A Kunitz-type invertase inhibitor mediates ethylene-induced sweetening. • A physiologically targeted ethylene + 1-MCP treatment offers an alternative to CIPC., Continuous ethylene supplementation suppresses postharvest sprouting, but it can increase reducing sugars, limiting its use as an alternative to chlorpropham for processing potatoes. To elucidate the mechanisms involved, tubers were treated after curing with or without the ethylene binding inhibitor 1-methylcyclopropene (1-MCP at 1 μL L−1 for 24 h), and then stored in air or air supplemented with continuous ethylene (10 μL L−1). Across three consecutive seasons, changes in tuber physiology were assessed alongside transcriptomic and metabolomic analysis. Exogenous ethylene alone consistently induced a respiratory rise and the accumulation of undesirable reducing sugars. The transient respiratory peak was preceded by the strong upregulation of two genes encoding 1-aminocyclopropane-1-carboxylate oxidase (ACO), typical of wound and stress induced ethylene production. Profiles of parenchymatic tissue highlighted that ethylene triggered abscisic acid (ABA) catabolism, evidenced by a steep fall in ABA levels and a transient rise in the catabolite phaseic acid, accompanied by upregulation of transcripts encoding an ABA 8ˊ-hydroxylase. Moreover, analysis of non-structural carbohydrate-related genes revealed that ethylene strongly downregulated the expression of the Kunitz-type invertase inhibitor, already known to be involved in cold-induced sweetening. All these ethylene-induced effects were negated by 1-MCP with one notable exception: 1-MCP enhanced the sprout suppressing effect of ethylene whilst preventing ethylene-induced sweetening. This study supports the conclusions that: i) tubers adapt to ethylene by regulating conserved pathways (e.g. ABA catabolism); ii) ethylene-induced sweetening acts independently from sprout suppression, and is similar to cold-induced sugar accumulation.

Blackheart (BH) is a physiological disorder of potato tubers in which internal tissue becomes discoloured during storage. The development of BH has been previously linked with general phenolic accumulation. In this study, five potato stocks cv. Maris Piper with different susceptibility to BH were selected across two consecutive seasons, whereupon targeted analysis of sugar and individual phenolic compounds in two tuber sections (flesh and heart) was conducted after storage at 1.5 °C or after one week at 15 °C. The most susceptible stock to BH had the highest accumulation of reducing sugars, while crypto- and neo-chlorogenic acids (chlorogenic acid isomers) were more abundant in flesh tissue of non-susceptible stocks. It is postulated that these metabolites may represent putative pre-symptomatic predictive biomarkers of stock susceptibility to BH.

Selenium (Se) enrichment of plants seems effective in enhancing the health-related properties of produce and in delaying plant senescence and fruit ripening. The current study investigated the effects of Se on tomato fruit ripening. Tomato (Solanum lycopersicum L.) plants were grown in hydroponics with different Se-enriched nutrient solutions. Se, as sodium selenate, was added at a rate of 0 mg LSelenium was absorbed by roots and translocated to leaves and fruit. Enrichment with Se did not significantly affect the qualitative parameters of fruit at commercial harvest; instead it delayed ripening by affecting specific ripening-related processes (respiration, ethylene production, color evolution) during postharvest. In the current experiment 100 g of tomato hydroponically grown with a 1.5 mg Se LThe cultivation of tomato plants in a Se-enriched solution appeared effective in producing tomato fruit with improved performance during storage and postharvest shelf life, and also with greater potential health-promoting properties. © 2018 Society of Chemical Industry.

Background: Grape juice is an important dietary source of health-promoting antioxidant molecules. Different factors may affect juice composition and nutraceutical properties. The effects of some of these factors (harvest time, pre-processing ethylene treatment of grapes and juice thermal pasteurization) were here evaluated, considering in particular the phenolic composition and antioxidant capacity. Results: Grapes (Vitis vinifera L., red-skinned variety Sangiovese) were collected twice in relation to the technological harvest (TH) and 12 days before TH (early harvest, EH) and treated with gaseous ethylene (1000 ppm) or air for 48 h. Fresh and pasteurized (78 °C for 30 min) juices were produced using a water bath. Three-way analysis of variance showed that the harvest date had the strongest impact on total polyphenols, hydroxycinnamates, flavonols, and especially on total flavonoids. Pre-processing ethylene treatment significantly increased the proanthocyanidin, anthocyanin and flavan-3-ol content in the juices. Pasteurization induced a significant increase in anthocyanin concentration. Antioxidant capacity was enhanced by ethylene treatment and pasteurization in juices from both TH and EH grapes. Conclusion: These results suggest that an appropriate management of grape harvesting date, postharvest and processing may lead to an improvement in nutraceutical quality of juices. Further research is needed to study the effect of the investigated factors on juice organoleptic properties.

The theme running through many of Luther Burbank’s breeding programs was to make plants more tailored to human uses. Mr. Burbank thought that the stone in plum fruits was unessential to a tree that was propagated vegetatively, so he chose stoneless plums as a breeding goal. He made two releases, ‘Miracle’ in 1903 and his final and almost perfect ‘Conquest’ in 1916, which he considered one of his best accomplishments in plum breeding. ‘Conquest’ had only a grain of stone and flavor and size comparable to the best French types of the time but was not commercially successful. In view of the current desire for convenience food such as seedless fruit (citrus, grapes, watermelon) and advanced knowledge of genetics and breeding technologies, we have taken up where Mr. Burbank left off in the production of a better than “almost perfect” stoneless plum. We began by locating what were most likely remnants from Mr. Burbank’s breeding program and we are now using 21st century technology to achieve a completely stoneless, high-quality plum fruit. These technologies include molecular markers, genetic engineering, and accelerated breeding cycles (FasTrack). Initial experiments had characterized the stoneless trait as a decrease in the number of endocarp cells that form the stone. We defined the time critical to the formation of endocarp by analyzing gene expression of a number of transcription factors involved with determining endocarp cells. We identified genes that were expressed differently during this period between normal stone cultivars and one of the stoneless cultivars. In addition, we targeted genes for genetic engineering to reduce the lignification in endocarp and to reduce or convert endocarp cells to non-lignifying cells. A system, FasTrack, using a flowering gene from poplar, has been incorporated to reduce the juvenility period and eliminate the seasonal aspect of fruiting to see the results of the breeding as well as the genetic engineering approach much faster. The combination of these approaches is now in place to attempt to improve on Mr. Burbank’s stoneless plum.

Potatoes represent an important staple food crop across the planet. Yet, to maintain tuber quality and extend availability, there is a necessity to store tubers for long periods often using industrial-scale facilities. In this context, preserving potato quality is pivotal for the seed, fresh and processing sectors. The industry has always innovated and invested in improved post-harvest storage. However, the pace of technological change has and will continue to increase. For instance, more stringent legislation and changing consumer attitudes have driven renewed interest in creating alternative or complementary post-harvest treatments to traditional chemically reliant sprout suppression and disease control. Herein, the current knowledge on biochemical factors governing dormancy, the use of chlorpropham (CIPC) as well as existing and chemical alternatives, and the effects of pre- and post-harvest factors to assure potato tuber quality is reviewed. Additionally, the role of genomics as a future approach to potato quality improvement is discussed. Critically, and through a more industry targeted research, a better mechanistic understanding of how the pre-harvest environment influences tuber quality and the factors which govern dormancy transition should lead to a paradigm shift in how sustainable storage can be achieved.

Grape juice is an important dietary source of health-promoting antioxidant molecules. Different factors may affect juice composition and nutraceutical properties. The effects of some of these factors (harvest time, pre-processing ethylene treatment of grapes and juice thermal pasteurization) were here evaluated, considering in particular the phenolic composition and antioxidant capacity.Grapes (Vitis vinifera L., red-skinned variety Sangiovese) were collected twice in relation to the technological harvest (TH) and 12 days before TH (early harvest, EH) and treated with gaseous ethylene (1000 ppm) or air for 48 h. Fresh and pasteurized (78 °C for 30 min) juices were produced using a water bath. Three-way analysis of variance showed that the harvest date had the strongest impact on total polyphenols, hydroxycinnamates, flavonols, and especially on total flavonoids. Pre-processing ethylene treatment significantly increased the proanthocyanidin, anthocyanin and flavan-3-ol content in the juices. Pasteurization induced a significant increase in anthocyanin concentration. Antioxidant capacity was enhanced by ethylene treatment and pasteurization in juices from both TH and EH grapes.These results suggest that an appropriate management of grape harvesting date, postharvest and processing may lead to an improvement in nutraceutical quality of juices. Further research is needed to study the effect of the investigated factors on juice organoleptic properties.

a b s t r a c t The physiological and molecular responses of ripe fruit to wounding were evaluated in two peach (Prunus persica) varieties ('Glohaven', GH, melting and 'BigTop', BT, slow melting nectarine) by comparing meso- carp samples from wedges (as in minimal processing) and whole fruit as the control. Slight differences between the two varieties were detected in terms of ethylene production, whereas total phenol and flavonoid concentrations, and PPO and POD enzyme activities showed a general increase in wounded GH but not in BT. This was associated with the better appearance of the BT wedges at the end of the exper- imental period (72 h). Microarray (genome-wide PEACH3.0) analysis revealed that a total number of 2218 genes were differentially expressed (p 1 or

Genomics approaches and transcriptome analyses are increasingly being used to elucidate mechanisms that regulate complex developmental processes such as fruit ripening and the evolution of quality-related biochemical changes during the postharvest phase. In peach (Prunus persica L.), projects aimed at isolating ESTs corresponding to genes expressed in different fruit tissues and the construction and use of tools such as microarrays has resulted in identification of basic information concerning hormonal regulation, in particular on the role of ethylene and auxin and their interplay and cross-talk during ripening. Functional genomics approaches have been undertaken for studies specifically targeted to identify and characterize genes involved in the peculiar response of peaches and nectarines to applications of 1-MCP and in the development of storage disorders.