Refine
Has Fulltext
- no (16)
Document Type
- Article (16) (remove)
Language
- English (16)
Is part of the Bibliography
- yes (16)
Keywords
- Carotenoids (4)
- carotenoids (4)
- Glucosinolates (3)
- Solanaceae (3)
- African indigenous vegetables (2)
- Pak choi (2)
- plant volatiles (2)
- 1-Methoxy-3-indolylmethyl glucosinolate (1)
- 7 macrophages (1)
- Aflatoxin B1 (1)
Institute
- Institut für Ernährungswissenschaft (16) (remove)
Tomato is susceptible to pest infestations by both spider mites and aphids. The effects of each individual pest on plants are known, whereas multiple-pest infestations have received little interest. We studied the effects of single-versus multiple-pest infestation by Tetranychus urticae and Myzus persicae on tomato biochemistry (Solanum lycopersicum) by combining a metabolomic approach and analyses of carotenoids using UHPLC-ToF-MS and volatiles using GC-MS. Plants responded differently to aphids and mites after 3 weeks of infestation, and a multiple infestation induced a specific metabolite composition in plants. In addition, we showed that volatiles emissions differed between the adaxial and abaxial leaf epidermes and identified compounds emitted particularly in response to a multiple infestation (cyclohexadecane, dodecane, aromadendrene, and beta-elemene). Finally, the carotenoid concentrations in leaves and stems were more affected by multiple than single infestations. Our study highlights and discusses the interplay of biotic stressors within the terpenoid metabolism.
The spider mite Tetranychus urticae Koch and the aphid Myzus persicae (Sulzer) both infest a number of economically significant crops, including tomato (Solanurn lycopersicum). Although used for decades to control pests, the impact of green lacewing larvae Chrysoperla carnea (Stephens) on plant biochemistry was not investigated. Here, we used profiling methods and targeted analyses to explore the impact of the predator and herbivore(s)-predator interactions on tomato biochemistry. Each pest and pest -predator combination induced a characteristic metabolite signature in the leaf and the fruit thus, the plant exhibited a systemic response. The treatments had a stronger impact on non-volatile metabolites including abscisic acid and amino acids in the leaves in comparison with the fruits. In contrast, the various biotic factors had a greater impact on the carotenoids in the fruits. We identified volatiles such as myrcene and alpha-terpinene which were induced by pest -predator interactions but not by single species, and we demonstrated the involvement of the phytohormone abscisic acid in tritrophic interactions for the first time. More importantly, C. carnea larvae alone impacted the plant metabolome, but the predator did not appear to elicit particular defense pathways on its own. Since the presence of both C. carnea larvae and pest individuals elicited volatiles which were shown to contribute to plant defense, C. carnea larvae could therefore contribute to the reduction of pest infestation, not only by its preying activity, but also by priming responses to generalist herbivores such as T urticae and M. persicae. On the other hand, the use of C. carnea larvae alone did not impact carotenoids thus, was not prejudicial to the fruit quality. The present piece of research highlights the specific impact of predator and tritrophic interactions with green lacewing larvae, spider mites, and aphids on different components of the tomato primary and secondary metabolism for the first time, and provides cues for further in-depth studies aiming to integrate entomological approaches and plant biochemistry.
Indigenous African leafy vegetables vary enormously in their secondary plant metabolites whereat genus and the species have a great impact. In African nightshade (Solanum scabrum), spiderplant (Cleome gynandra), amaranth (Amaranthus cruentus), cowpea (Vigna unguiculata), Ethiopian kale (Brassica carinata) and common kale (Brassica oleracea) the specific secondary metabolite profile was elucidated and gained detailed data about carotenoids, chlorophylls, glucosinolates and phenolic compounds all having an appropriate contribution to health beneficial properties of indigenous African leafy vegetables. Exemplarily, various quercetin glycosides such as quercetin-3-rutinoside occur in high concentrations in African nightshade, spiderplant, and amaranth between similar to 1400-3300 mu g/g DW. Additionally the extraordinary hydroxydnnamic acid derivatives such as glucaric isomers and isocitric acid isomers are found especially in amaranth (up to similar to 1250 mu g/g DW) and spiderplant (up to 120 mu g/g DW). Carotenoids concentrations are high in amaranth (up to 101.7 mu g/g DW) and spiderplants (up to 64.7 mu g/g DW) showing high concentrations of beta-carotene, the pro-vitamin A. In contrast to the ubiquitous occurring phenolics and carotenoids, glucosinolates are only present in the Brassicales species Ethiopian kale, common kale and spiderplant characterized by diverse glucosinolate profiles. Generally, the consumption of a variety of these indigenous African leafy vegetables can be recommended to contribute to different benefits such as antioxidant activity, increase pro-vitamin A and anticancerogenic compounds in a healthy diet. (C) 2017 Elsevier Ltd. All rights reserved.
Plant growth-promoting bacteria (PGPB) affect host physiological processes in various ways. This study aims at elucidating the dependence of bacterial-induced growth promotion on the plant genotype and characterizing plant metabolic adaptations to PGPB. Eighteen Arabidopsis thaliana accessions were inoculated with the PGPB strain Kosakonia radicincitans DSM 16656(T). Colonisation pattern was assessed by enhanced green fluorescent protein (eGFP)-tagged K. radicincitans in three A. thaliana accessions differing in their growth response. Metabolic impact of bacterial colonisation was determined for the best responding accession by profiling distinct classes of plant secondary metabolites and root exudates. Inoculation of 18 A. thaliana accessions resulted in a wide range of growth responses, from repression to enhancement. Testing the bacterial colonisation of three accessions did not reveal a differential pattern. Profiling of plant secondary metabolites showed a differential accumulation of glucosinolates, phenylpropanoids and carotenoids in roots. Analysis of root exudates demonstrated that primary and secondary metabolites were predominantly differentially depleted by bacterial inoculation. The plant genotype controls the bacterial growth promoting traits. Levels of lutein and beta-carotene were elevated in inoculated roots. Supplementing a bacterial suspension with beta-carotene increased bacterial growth, while this was not the case when lutein was applied, indicating that beta-carotene could be a positive regulator of plant growth promotion.
Intercropping is widespread in small-holder farming systems in tropical regions and is also practiced in the cultivation of indigenous vegetables, to alleviate the multiple burdens of malnutrition. Due to interspecific competition and/or complementation between intercrops, intercropping may lead to changes in plants accumulation of minerals and secondary metabolites and hence, alter nutritional quality for consumers. Intercropping aims to intensify land productivity, while ensuring that nutritional quality is not compromised. This study aimed to investigate changes in minerals and secondary plant metabolites in intercropped Brassica carinata and Solanum scabrum, two important African indigenous vegetables, and evaluated the suitability of this combination for dryer areas. B. carinata and S. scabrum were grown for 6 weeks under controlled conditions in a greenhouse trial. Large rootboxes (8000 cm(3) volume) were specifically designed for this experiment. Each rootbox was planted with two plants, either of the same plant species (mono) or one of each plant species (mixed). A quartz sand/soil substrate was used and fertilized adequately for optimal plant growth. During the last 4 weeks of the experiment, the plants were either supplied with optimal (65% WHC) or low (30% WHC) irrigation, to test the effect of a late-season drought. Intercropping increased total glucosinolate content in B. carinata, while maintaining biomass production and the contents of other health related minerals in both B. carinata and S. scabrum. Moreover, low irrigation led to an increase in carotene accumulation in both mono and intercropped S. scabrum, but not in B. carinata, while the majority of kaempferol glycosides and hydroxycinnamic acid derivatives of both species were decreased by intercropping and drought treatment. This study indicates that some health-related phytochemicals can be modified by intercropping or late-season drought, but field validation of these results is necessary before definite recommendation can be made to stakeholders.
Amaranth is presently an underutilized crop despite its high content of micronutrients/bioactive phytochemicals and its capacity to thrive in harsh environmental condition. The present study aimed at determining the health benefits of Amaranthus cruentus L. in terms of protection against DNA damage induced by the mycotoxin aflatoxin B1 (AFB1) and oxidative stress using comet assay. The antioxidant potential was further investigated using electron paramagnetic resonance spectroscopy (EPR) and an ARE/Nrf2 reporter gene assay in vitro in a human liver model using the HepG2 cell line. Ethanolic extracts from fresh leaves grown under controlled conditions were used and additionally analyzed for their phytochemical content using liquid chromatography-mass spectrometry (LC-MS). The extracts inhibited both AFB1- and oxidative stress-induced DNA damage in a concentration dependent way with a maximum effect of 57% and 81%, respectively. Oxidative stress triggered using ferrous sulfate was blocked by up to 38% (EPR); the potential to induce antioxidant enzymes using ARE/Nrf2-mediated gene expression was also confirmed. Based on these in vitro findings, further studies on the health-protecting effects of A. cruentus are encouraged to fully explore its health promoting potential and provide the scientific basis for encouraging its cultivation and consumption.
Plant cultivation and processing may impact nutrient and phytochemical content of vegetables. The present study aimed at determining the influence of cultivation and processing on the health promoting capacity of African nightshade (Solanum scabrum Mill.) leaves, an indigenous vegetable, rich in nutrients and phytochemicals. Anti-genotoxicity against the human liver carcinogen aflatoxin B1 (AFB(1)) as determined by the comet assay and radical oxygen species (ROS) scavenging capacity of ethanolic and aqueous extracts were investigated in human derived liver (HepG2) cells. ROS scavenging activity was assessed using electron paramagnetic spin resonance and quantification of ARE/Nrf2 mediated gene expression. The cultivation was done under different environmental conditions. The processing included fermentation and cooking; postharvest ultraviolet irradiation (UV-C) treatment was also investigated. Overall, S. scabrum extracts showed strong health promoting potential, the highest potential was observed with the fermented extract, which showed a 60% reduction of AFB(1) induced DNA damage and a 38% reduction in FeSO4 induced oxidative stress. The content of total polyphenols, carotenoids and chlorophylls was indeed affected by cultivation and processing. Based on the present in vitro findings consumption of S. scabrum leaves could be further encouraged, preferentially after cooking or fermentation of the plant.
Light quality-induced changes of carotenoid composition in pak choi Brassica rapa ssp. chinensis
(2019)
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 beta-carotene content which could be correlated to changes in the transcript levels of beta-carotene hydroxylase 1 (beta-OHASE1). Further investigations implied a redox controlled gene expression of beta-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.
Tea aroma is one of the most important factors affecting the character and quality of tea. Here we describe the practical application of methyl jasmonate (MeJA) to improve the aroma quality of teas. The changes of selected metabolites during crucial tea processing steps, namely, withering, fixing and rolling, and fermentation, were analyzed. MeJA treatment of tea leaves (12, 24, 48, and 168 h) greatly promotes the aroma quality of green, oolong, and black tea products when comparing with untreated ones (0 h) and as confirmed by sensory evaluation. MeJA modulates the aroma profiles before, during, and after processing. Benzyl alcohol, benzaldehyde, 2-phenylethyl alcohol, phenylacetaldehyde, and trans-2-hexenal increased 1.07- to 3-fold in MeJA-treated fresh leaves and the first two maintained at a higher level in black tea and the last two in green tea. This correlates with a decrease in aromatic amino acids by more than twofold indicating a direct relation to tryptophan- and phenylalanine-derived volatiles. MeJA-treated oolong tea was characterized by a more pleasant aroma. Especially the terpenoids linalool and oxides, geraniol, and carvenol increased by more than twofold.
Young kale and pea leaves are rich in secondary plant metabolites (SPMs) whose profile can be affected by ultraviolet B (UVB) radiation. Carotenoids and flavonoids in kale and pea exposed to narrow-banded UVB, produced by innovative light-emitting diodes (LEDs), and subsequently used for breadmaking were investigated for the first time, thus combining two important strategies to increase the SPMs intake. Breads were also fortified with protein-rich lentil flour. Antioxidant activity in the ‘vegetable breads’ indicated health-promoting effects. Lentil flour increased the antioxidant activity in all of the ‘vegetable breads’. While carotenoids and chlorophylls showed a minor response to UVB treatment, kaempferol glycosides decreased in favor of increasing quercetin glycosides, especially in kale. Additionally, breadmaking caused major decreases in carotenoids and a conversion of chlorophyll to bioactive degradation products. In ‘kale breads’ and ‘pea breads’, 20% and 84% of flavonoid glycosides were recovered. Thus, kale and pea leaves seem to be suitable natural ingredients for producing innovative Functional Foods.