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Tomato ( Solanum lycopersicum ): Chemistry and Human Health, 2nd Edition
Fruit ripening is a complex process involving dynamic changes to metabolites and is controlled by multiple factors, including transcription factors (TFs). Several TFs are reportedly essential regulators of tomato (Solanum lycopersicum) fruit ripening. To evaluate the effects of specific TFs on metabolite accumulation during fruit ripening, we combined CRISPR/Cas9-mediated mutagenesis with metabolome and transcriptome analyses to explore regulatory mechanisms. Specifically, we generated various genetically engineered tomato lines that differed regarding metabolite contents and fruit colors. The metabolite and transcript profiles indicated that the selected TFs have distinct functions that control fruit metabolite contents, especially carotenoids and sugars. Moreover, a mutation to ELONGATED HYPOCOTYL5 (HY5) increased tomato fruit fructose and glucose contents by approximately 20% (relative to the wild-type levels). Our in vitro assay showed that HY5 can bind directly to the G-box cis-element in the Sugars Will Eventually be Exported Transporter (SWEET12c) promoter to activate expression, thereby modulating sugar transport. Our findings provide insights into the mechanisms regulating tomato fruit ripening and metabolic networks, providing the theoretical basis for breeding horticultural crops that produce fruit with diverse flavors and colors.
Plant based medicines have been a part of traditional healthcare in most parts of the world for thousands of years. Many medicinal plants are used daily in Ayurvedic practices. In India more than 7,000 medicinal plant species are known. The medicinal plants find application in pharmaceutical, cosmetic, agricultural and food industry. Starting from the ancient time, medicinal plants have been used to prevent and treat various health problems. There is an increasing demand for the herbal drug treatment of various ailments and many plant drugs from ayurvedic system are being explored globally. Tomato (Lycopersicon esculentum L.) is one of the most widely consumed vegetable, and is known for various medicinal properties in traditional medicinal system and use to cure a variety of diseases. In last few decades, Lycopersicon esculentum is extensively studied for its medicinal properties by advanced scientific techniques and a variety of bioactive compounds have been isolated from the different parts of the plant and were analysed pharmacologically. In our present investigation phytochemical analysis of flowers of Lycopersicon esculentum has been evaluated for the presence of bioactive compounds using various polarity solvents including hexane, chloroform, methanol and water. The study revealed the presence of alkaloids, flavonoids, terpenoids, phenolic compounds, sterols, carbohydrates, glycosides and tannins. The results suggest that methanolic extract of Lycopersicon esculentum flower has promising therapeutic potential, its pharmacological properties which if properly harness can be used in the management of various diseases and can serve as a base for the development of novel potent drug.
Shade nets arewidely used to protect floricultural crops fromexcessive radiation, wind, hail, and birds. Although black nets are most frequently used, growers are experimenting with colored, gray, and white dispersive netting to impact vegetative vigor, dwarfing, branching, leaf variegation, and timing of flowering. We monitored environmental data inside replicated shadehouse structures (10 3 10 3 3 m high) with full covering of red, blue, pearl, and black nets (all 50% nominal shading factor) in central Florida over 12 months. Actual photosynthetically active radiation (PAR, mmol·mL2·sL1) was reduced most by black nets (55% to 60% shading factor depending on the season) and least under red nets (41% to 51%) with blue and pearl nets intermediate. Spectral analysis revealed blue nets had distinctive peaks at the blue (450 to 495 nm) and far-red beyond 750 nm. Red nets had a minor peak '400 nm and major transmittance beyond 590 nm. Pearl nets transmitted more light above 400 nm compared with black nets but did not otherwise alter spectral composition in the visible range. No nets had red/far-red (R/FR) ratios (600 to 700/700 to 800 nm) significantly greater than ambient (close to 1), whereas blue nets had a consistently lowest R/FR ratio of '0.8. Both ultraviolet-B and ultraviolet-A (280 to 400 nm) were reduced most by pearl nets and least by red nets. We also noted elevated temperatures and wind resistance (but not relative humidity) under colored and pearl nets compared with black, probably as a result of the different net porosities. Our study documents the different environmental modifications inside structures covered with black, colored, and photoneutral translucent nets, which will help predict or interpret specific plant responses.
Fruits and vegetables are generally considered as important contributors to a healthy diet and their intake is extremely helpful to reduce the risk of specific diseases like cancers, cardiovascular diseases, neural tube defects, and cataracts. Bioactive constituents from fruits and vegetables, such as carotenoids, folic acid and dietary fiber appear to play important roles in the prevention of these diseases. Carotenoids and their derivatives are versatile isoprenoids and play a vital role in plants and animals, starting from cellular antioxidant to gene regulation and so their importance at cellular and molecular level is well established. The most significant aspect of carotenoids in our diet is the antioxidant and provitamin A activity, and also the color that they impart to our food. The composition and bioavailability of carotenoids in food are significantly influenced by processing and other post-harvest technologies. This review discusses the theoretical aspects and recent developments in structural properties, biosynthesis and enhancement, processing, methods of analysis, composition in fruits and vegetables, and bioaccessibility and bioavailability of carotenoids. Additionally, future research challenges in this context are identified.
Background
Tomato fruit ripening is controlled by ethylene and is characterized by a shift in color from green to red, a strong accumulation of lycopene, and a decrease in β-xanthophylls and chlorophylls. The role of other hormones, such as auxin, has been less studied. Auxin is retarding the fruit ripening. In tomato, there is no study of the carotenoid content and related transcript after treatment with auxin.
Results
We followed the effects of application of various hormone-like substances to “Mature-Green” fruits. Application of an ethylene precursor (ACC) or of an auxin antagonist (PCIB) to tomato fruits accelerated the color shift, the accumulation of lycopene, α-, β-, and δ-carotenes and the disappearance of β-xanthophylls and chlorophyll b. By contrast, application of auxin (IAA) delayed the color shift, the lycopene accumulation and the decrease of chlorophyll a. Combined application of IAA + ACC led to an intermediate phenotype. The levels of transcripts coding for carotenoid biosynthesis enzymes, for the ripening regulator Rin, for chlorophyllase, and the levels of ethylene and abscisic acid (ABA) were monitored in the treated fruits. Correlation network analyses suggest that ABA, may also be a key regulator of several responses to auxin and ethylene treatments.
Conclusions
The results suggest that IAA retards tomato ripening by affecting a set of (i) key regulators, such as Rin, ethylene and ABA, and (ii) key effectors, such as genes for lycopene and β-xanthophyll biosynthesis and for chlorophyll degradation.
The response of plants to stress such as UV-radiation or drought highly depends on the species, cultivar, plant organ, developmental stage, and furthermore, is influenced by ecophysiological interactions. Drought stress as well as UV irradiation are the most adverse factors for plant growth and productivity. In the present study, the interactive effect of UV-B and drought stress on biomass, primary and secondary metabolites, and mediated enzyme activity of phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) was investigated in lettuce (Lactuca sativa L.). It was found that biomass production decreased in response to both stressors, while dry matter, total phenolic contents and the flavonol quercetin were not significantly affected by UV-B and drought stress, neither solely nor in combination. In contrast, anthocyanins and luteolin accumulated only in response to drought stress. However, the precursor amino acid proline as well as the activity of PAL increased under conditions of increased UV-B and water deficit. Thus, the present results deduce that both stressors acted either synergistically or to some extent antagonistically in terms of inducing plant protective mechanisms.
Prostate cancer (PCa) is the second leading cause of cancer-related deaths in U.S. men. PCa is a slow-growing cancer; therefore, identifying dietary interventions to reduce the risk or progression of PCa could greatly impact public health. A growing body of evidence has identified several foods that may reduce the risk of PCa. Mechanistic studies have investigated individual bioactives from foods to identify their anticarcinogenic properties; however, it is also important to study the whole food. In rodent models of PCa, we have shown that consumption of whole tomato powder was more effective than lycopene alone in reducing PCa progression. In a transgenic mouse model of PCa, broccoli consumption significantly altered expression of genes involved in the epithelial-mesenchymal transition, which may be a mechanism by which broccoli intake has been associated with a reduced risk of aggressive PCa. Combinations of foods may be more protective than individual foods, but this should not be assumed, as antagonistic activity between bioactives has been suggested. We have investigated the combinations of tomato and broccoli and tomato and soy germ. Future diet and cancer research should continue to focus on whole foods and combinations of foods for better translation into recommendations for the public.
With the purpose of increasing the concentration of bioactive compounds and evaluating the influence of climatic factors on the tomato, cultivar 'Liberto', fruits were exposed to physical stress in a glasshouse in Berlin before harvesting through the application of moderate doses of UV-B radiation in November, 2007 and in May, 2008. The objective was to investigate whether its use had an eliciting effect on the secondary metabolism that resulted in a change in the concentration of bioactive compounds. Two UV-B radiation doses were used: a) range between 0.075 and 0.105 Wh m-2 and b) 0.15 Wh m-2. The mean photosynthetic photon flux density (PPDF) was 18.8 mol m-2 d-1 in May and 5.9 mol m-2 d-1 in November. After 22 hours of adaptation time, the ripe tomato fruits were harvested to determine the lycopene and ß-carotene contents. The results showed that the exposure of ripe fruits to UV-B caused ß-carotene accumulation in the November-treatment. Temperature and PPDF showed a strong influence on ß-carotene and lycopene accumulation, as well as on the dry matter content. The May- and November-treatments differed significantly with respect to carotenoid content between the non-treated fruits and those treated with UV-B radiation.
The combined effect of increasing concentrations of NaCl in the irrigation water and fertilization with different nitrogen sources on the chemical composition of tomato (Lycopersicon esculentum Mill.) fruit was investigated. Increasing water salinity from 0.5 dS m-1 (non-salinized control) to 15.7 dS m-1 resulted in both reduced fruit size and fruit water content, whereas it caused an increase in soluble solids, carbohydrates, sodium and chloride concentrations. Titratable acidity increased upon irrigation with saline water, whereas the fruit redness significantly decreased. In addition, salinity reduced P, K+, Mg2+ and NO3- fruit concentrations. Total carotenoids and lycopene concentrations expressed on both fresh- and dry-weight basis gradually increased from the non-salinized control to the 4.4 dS m-1 treatment (approximately 0.25% NaCl w/v) and they decreased at electrical conductivities of the irrigation water higher than 4.4 dS m-1. Overall these data show that it is possible to improve carotenoid content and antioxidative activity of tomato, with an acceptable yield reduction, by irrigating with saline water containing NaCl up to 0.25% (w/v).
We show that phytochromes modulate differentially various facets of light-induced ripening of tomato fruit (Solanum lycopersicum L.). Northern analysis demonstrated that phytochrome A mRNA in fruit accumulates 11.4-fold during ripening. Spectroradiometric measurement of pericarp tissues revealed that the red to far-red ratio increases 4-fold in pericarp tissues during ripening from the immature-green to the red-ripe stage. Brief red-light treatment of harvested mature-green fruit stimulated lycopene accumulation 2.3-fold during fruit development. This red-light-induced lycopene accumulation was reversed by subsequent treatment with far-red light, establishing that light-induced accumulation of lycopene in tomato is regulated by fruit-localized phytochromes. Red-light and red-light/far-red-light treatments during ripening did not influence ethylene production, indicating that the biosynthesis of this ripening hormone in these tissues is not regulated by fruit-localized phytochromes. Compression analysis of fruit treated with red light or red/far-red light indicated that phytochromes do not regulate the rate or extent of pericarp softening during ripening. Moreover, treatments with red or red/far-red light did not alter the concentrations of citrate, malate, fructose, glucose, or sucrose in fruit. These results are consistent with two conclusions: (a) fruit-localized phytochromes regulate light-induced lycopene accumulation independently of ethylene biosynthesis; and (b) fruit-localized phytochromes are not global regulators of ripening, but instead regulate one or more specific components of this developmental process.