Carotenoids as part of the photosystems are crucial for their assembly, light-harvesting, and photoprotection. Light of different wavelengths impacts the composition and structure of photosystems, ...thus offering the possibility to influence the carotenoid concentrations and composition in photosystems by illumination with specific narrow-banded light spectra. Key components involved in the regulation of gene transcription are still poorly characterized, particularly in leafy vegetables as compared to model plants. In particular, the effect of different light qualities and its connection to redox control mechanisms, which also determine the photosystem composition and structure, is not yet well understood. Furthermore, light quality effects are species-dependent, and thus, increase the need to perform research on individual vegetable species such as pak choi Brassica rapa ssp. chinensis.
Here, we investigated the carotenoid concentrations and composition of pak choi sprouts grown for 6 days under blue, red, or white light emitting diodes (LEDs) as light source. After 6 days, the total carotenoid content was the highest under white and slightly reduced under blue or red LEDs. Blue, red, and white light differently affected the carotenoid composition mainly due to variations of the β-carotene content which could be correlated to changes in the transcript levels of β-carotene hydroxylase 1 (β-OHASE1). Further investigations implied a redox controlled gene expression of β-OHASE1. In addition, transcription factors related to light signaling and the circadian clock differed in their transcriptional abundance after exposure to blue and red light. RNA-Seq analysis also revealed increased transcript levels of genes encoding the outer antenna complex of photosystem II under red compared to blue light, indicating an adjustment of the photosystems to the different light qualities which possibly contributed to the alternations in the carotenoid content and composition.
•Different narrow-banded light spectra affected the lutein/β-carotene ratio in pak choi.•The β-carotene content correlated with changes in the transcript levels of the β-carotene hydroxylase 1 (β-OHASE1).•The results suggest a redox control of the β-OHASE1 gene expression.•RNA-Seq revealed an adjustment of the outer antenna complex of the photosystem II in response to different light spectra.•Transcription factors related to light signaling/circadian clock differed after exposure to blue and red light.
New vegetable production systems, such as vertical farming, but also well-established in-door production methods led to the implementation of light emitting diodes (LEDs). LEDs are the most important ...light sources in modern indoor-production systems and offer the possibility for enhancing growth and specific metabolites in planta. Even though the number of studies investigating the effects of LED lighting on vegetable quality has increased, the knowledge about genus variability is limited. In the present study, the effect of different LED spectra on the metabolic and transcriptional level of the carotenoid metabolism in five different Brassica sprouts was investigated. Cruciferous vegetables are one of the main food crops worldwide. Pak choi (Brassica rapa ssp. chinensis), cauliflower (Brassica oleracea var. botrytis), Chinese cabbage (Brassica rapa ssp. pekinensis), green kale (Brassica oleracea ssp. sabellica) and turnip cabbage (Brassica oleracea spp. gongylodes) sprouts were grown under a combination of blue & white LEDs, red & white LEDs or only white LEDs to elucidate the genus-specific carotenoid metabolism.
Genus-specific changes in plant weight and on the photosynthetic pigment levels as well as transcript levels have been detected. Interestingly, the transcript levels of the three investigated carotenoid biosynthesis genes phytoene synthase (PSY), β-cyclase (βLCY) and β-carotene hydroxylase (βOHASE1) were increased under the combination of blue & white LEDs in the majority of the Brassica sprouts. However, only in pak choi, the combination of blue & white LEDs enhanced the carotenoid levels by 14% in comparison to only white LEDs and by ~ 19% in comparison to red & white LEDs.
The effects of light quality differ within a genus which leads to the conclusion that production strategies have to be developed for individual species and cultivars to fully benefit from LED technology.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In the face of a growing world population and limited land, there is an urgent demand for higher productivity of food crops, and cultivation systems must be adapted to future needs. Sustainable crop ...production should aim for not only high yields, but also high nutritional values. In particular, the consumption of bioactive compounds such as carotenoids and flavonoids is associated with a reduced incidence of non-transmissible diseases. Modulating environmental conditions by improving cultivation systems can lead to the adaption of plant metabolisms and the accumulation of bioactive compounds. The present study investigates the regulation of carotenoid and flavonoid metabolisms in lettuce (
L.) grown in a protected environment (polytunnels) compared to plants grown without polytunnels. Carotenoid, flavonoid and phytohormone (ABA) contents were determined using HPLC-MS and transcript levels of key metabolic genes were analyzed by RT-
PCR. In this study, we observed inverse contents of flavonoids and carotenoids in lettuce grown without or under polytunnels. Flavonoid contents on a total and individual level were significantly lower, while total carotenoid content was higher in lettuce plants grown under polytunnels compared to without. However, the adaptation was specific to the level of individual carotenoids. For instance, the accumulation of the main carotenoids lutein and neoxanthin was induced while the β-carotene content remained unchanged. In addition, our findings suggest that the flavonoid content of lettuce depends on transcript levels of the key biosynthetic enzyme, which is modulated by UV light. A regulatory influence can be assumed based on the relation between the concentration of the phytohormone ABA and the flavonoid content in lettuce. In contrast, the carotenoid content is not reflected in transcript levels of the key enzyme of either the biosynthetic or the degradation pathway. Nevertheless, the carotenoid metabolic flux determined using norflurazon was higher in lettuce grown under polytunnels, suggesting posttranscriptional regulation of carotenoid accumulation, which should be an integral part of future studies. Therefore, a balance needs to be found between the individual environmental factors, including light and temperature, in order to optimize the carotenoid or flavonoid contents and to obtain nutritionally highly valuable crops in protected cultivation.
Carotenoids and chlorophylls are among the most widely distributed pigments in nature that play essential roles in the photosynthetic apparatus and confer diverse colours in plants. Among all ...vegetables, cauliflower (Brassica oleracea L. ssp. var. botrytis) is rich in phytochemicals and is an important crop grown all over the world. This study investigates carotenoid and chlorophyll concentrations in differently pigmented cultivars and elucidates the role of transcriptional regulation of carotenoid accumulation including lutein and β-carotene. Here, we characterised changes in pigments by UHPLC-DAD-ToF-MS and changes in transcript levels of carotenoid metabolic genes by qRT-PCR in florets and leaves of orange (‘Jaffa’ and ‘Sunset’), purple (‘Di Sicilia Violetto’ and ‘Graffiti’), green (‘Trevi’) and white (‘Clapton’) cultivars. Transcript levels of all carotenoid metabolic genes showed different transcript level patterns in the leaves and florets. Compared to the other cultivars, the orange cultivars had the highest levels of β-carotene in the florets and lutein in the leaves resulting in changes lutein/β-carotene ratios. In the green cultivar, higher transcript levels were also found, especially for phytoene synthase and phytoene desaturase genes of the core biosynthesis pathway. However, no increased carotenoid concentrations were observed, possibly due to a higher carotenoid turnover induced by the carotenoid cleavage dioxygenase 4 in the green cultivar. In the white (‘Clapton’) and purple (‘Di Sicilia Violetto’ and ‘Graffiti’) cultivars the phytoene desaturase transcript levels as well as carotenoid concentrations were low. Chlorophyll concentrations changed in trend comparable to the carotenoid concentrations and were only significantly lower in the leaves of the orange cultivar ‘Jaffa’. Also, the chlorophyll a/b ratio changed in ‘Jaffa’. In florets the highest chlorophylls concentrations were observed for the green cultivar (‘Trevi’) and the purple cultivar (‘Di Sicilia Violetto’). Taken together, the study demonstrates the complex source-sink relationship of carotenoid accumulation in different coloured cauliflower.
•The influence of the type of emulsifier on stability of emulsion.•Combination of bioactive protein components in a concept of an emulsion.•The use of a food based emulsion system in combination with ...a cell culture medium.•The influence of the type of emulsifier with regard to cytotoxicity related issues.•The effect of emulsifiers on the absorption of lutein from emulsions by HT29 cells.
The carotenoid lutein can improve human health. Since only a fraction is absorbed from food, lutein supplementation might be recommended. Emulsions could be good carrier systems to improve the bioavailability of lutein. Six different emulsifier compositions were used in this study to prepare lutein-loaded emulsions: β-lactoglobulin, β-lactoglobulin/lecithin, Biozate 1, Biozate 1/lecithin, Tween 20 and Tween 20/lecithin. The droplet size, resistance to creaming, lutein stability, cytotoxicity and lutein uptake by HT29 cells were investigated. The whey protein β-lactoglobulin, the whey protein hydrolysate Biozate 1 and the combination with lecithin brought the most promising results. The small droplet sizes and resistance to creaming were an indication of physical stable emulsions. Furthermore, these emulsifiers prevented oxidation of lutein. The choice of emulsifier had a strong impact on the uptake by HT29 cells. The highest lutein absorption was observed with the combination of Biozate 1 and lecithin.
Carotenoids have the potential to improve the human health which leads to an increasing consumer demand for carotenoid-rich vegetables. The implementation of new, less energy-consuming vegetable ...production systems using artificial light such as light-emitting diodes (LEDs) is essential. In the present study, pak choi (
Brassica rapa
ssp.
chinensis
‘Black Behi’) sprouts were grown under a combination of blue and white LEDs, red and white LEDs or only white LEDs for 7 days. Total carotenoid levels of ~ 700 ng/mg DM were measured under white LEDs. The combination of blue and white LEDs increased the carotenoid levels by ~ 15% in comparison to only white LEDs, while red and white LEDs reduced them. The transcript levels of important carotenoid metabolism-related genes were enhanced under blue and white LEDs. Phytoene measurement after Norflurazon-treatment, a phytoene desaturase inhibitor, revealed that phytoene increased by 38% (37.5 µM Norflurazon) and by 56% (50.0 µM Norflurazon) after growth under blue and white LEDs in comparison to only white LEDs suggesting an up-regulation of the upper carotenoid biosynthetic pathway. Thus, the transcript levels and the enhanced phytoene levels correlated well with the higher accumulation of carotenoids under blue and white LEDs. Furthermore, a comparison to sprouts grown under blue LEDs without additional white LEDs showed that blue light alone does not increase the phytoene levels after Norflurazon-treatment. Overall, this study demonstrated a beneficial effect of a higher blue light percentage in growing carotenoid-rich pak choi sprouts, and implies that an increased biosynthesis within the upper carotenoid biosynthetic pathway is responsible for the enhanced carotenoid accumulation.
Graphical abstract
Large quantities of biological waste are generated at various steps within the food production chain and a great utilization potential for this solid biological waste exists apart from the current ...main usage for the feedstuff sector. It remains unclear how the usage of biological waste as compost modulates plant metabolites. We investigated the effect of biological waste of the processing of coffee, aronia, and hop added to soil on the plant metabolite profile by means of liquid chromatography in pak choi sprouts. Here we demonstrate that the solid biological waste composts induced specific changes in the metabolite profiles and the changes are depending on the type of the organic residues and its concentration in soil. The targeted analysis of selected plant metabolites, associated with health beneficial properties of the Brassicaceae family, revealed increased concentrations of carotenoids (up to 3.2-fold) and decreased amounts of glucosinolates (up to 4.7-fold) as well as phenolic compounds (up to 1.5-fold).
The degeneration of the retinal pigment epithelium caused by oxidative damage is a stage of development in age-related macular degeneration (AMD). The carotenoid lutein is a major macular pigment ...that may reduce the incidence and progression of AMD, but the underlying mechanism is currently not fully understood. Carotenoids are known to be direct antioxidants. However, carotenoids can also activate cellular pathways resulting in indirect antioxidant effects. Here, we investigate the influence of lutein on the activation of nuclear factor erythroid 2-related factor 2 (Nrf2) target genes in human retinal pigment epithelial cells (ARPE-19 cells) using lutein-loaded Tween40 micelles. The micelles were identified as a suitable delivery system since they were nontoxic in APRE-19 cells up to 0.04% Tween40 and led to a cellular lutein accumulation of 62 μM ± 14 μM after 24 h. Lutein significantly enhanced Nrf2 translocation to the nucleus 1.5 ± 0.4-fold compared to that of unloaded micelles after 4 h. Furthermore, lutein treatment for 24 h significantly increased the transcripts of NAD(P)H:quinone oxidoreductase 1 (NQO1) by 1.7 ± 0.1-fold, glutamate-cysteine ligase regulatory subunit (GCLm) by 1.4 ± 0.1-fold, and heme oxygenase-1 (HO-1) by 1.8 ± 0.3-fold. Moreover, we observed a significant enhancement of NQO1 activity by 1.2 ± 0.1-fold. Collectively, this study indicates that lutein not only serves as a direct antioxidant but also activates Nrf2 in ARPE-19 cells.
Hepatic steatosis is recognized as hepatic presentation of the metabolic syndrome. Hyperinsulinaemia, which shifts fatty acid oxidation to de novo lipogenesis and lipid storage in the liver, appears ...to be a principal elicitor particularly in the early stages of disease development. The impact of PGE2, which has previously been shown to attenuate insulin signaling and hence might reduce insulin-dependent lipid accumulation, on insulin-induced steatosis of hepatocytes was studied. The PGE2-generating capacity was enhanced in various obese mouse models by the induction of cyclooxygenase 2 and microsomal prostaglandin E-synthases (mPGES1, mPGES2). PGE2 attenuated the insulin-dependent induction of SREBP-1c and its target genes glucokinase and fatty acid synthase. Nevertheless, PGE2 enhanced incorporation of glucose into hepatic triglycerides synergistically with insulin. This was most likely due to a combination of a PGE2-dependent repression of (1) the key lipolytic enzyme adipose triglyceride lipase, (2) carnitine–palmitoyltransferase 1, a key regulator of mitochondrial β-oxidation, and (3) microsomal transfer protein, as well as (4) apolipoprotein B, key components of the VLDL synthesis. Repression of PGC1α, a common upstream regulator of these genes, was identified as a possible cause. In support of this hypothesis, overexpression of PGC1α completely blunted the PGE2-dependent fat accumulation. PGE2 enhanced lipid accumulation synergistically with insulin, despite attenuating insulin signaling and might thus contribute to the development of hepatic steatosis. Induction of enzymes involved in PGE2 synthesis in in vivo models of obesity imply a potential role of prostanoids in the development of NAFLD and NASH.
Hepatic steatosis is recognized as hepatic presentation of the metabolic syndrome. Hyperinsulinaemia, which shifts fatty acid oxidation to de novo lipogenesis and lipid storage in the liver, appears ...to be a principal elicitor particularly in the early stages of disease development. The impact of PGE, which has previously been shown to attenuate insulin signaling and hence might reduce insulin-dependent lipid accumulation, on insulin-induced steatosis of hepatocytes was studied. The PGE-generating capacity was enhanced in various obese mouse models by the induction of cyclooxygenase 2 and microsomal prostaglandin E-synthases (mPGES1, mPGES2). PGE attenuated the insulin-dependent induction of SREBP-1c and its target genes glucokinase and fatty acid synthase. Nevertheless, PGE enhanced incorporation of glucose into hepatic triglycerides synergistically with insulin. This was most likely due to a combination of a PGE-dependent repression of (1) the key lipolytic enzyme adipose triglyceride lipase, (2) carnitine-palmitoyltransferase 1, a key regulator of mitochondrial beta-oxidation, and (3) microsomal transfer protein, as well as (4) apolipoprotein B, key components of the VLDL synthesis. Repression of PGC1α, a common upstream regulator of these genes, was identified as a possible cause. In support of this hypothesis, overexpression of PGC1α completely blunted the PGE-dependent fat accumulation. PGE enhanced lipid accumulation synergistically with insulin, despite attenuating insulin signaling and might thus contribute to the development of hepatic steatosis. Induction of enzymes involved in PGE synthesis in in vivo models of obesity imply a potential role of prostanoids in the development of NAFLD and NASH.
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