Engineered nanomaterials (ENMs) possess remarkable physicochemical characteristics suitable for different applications in medicine, pharmaceuticals, biotechnology, energy, cosmetics and electronics. ...Because of their ultrafine size and high surface reactivity, ENMs can enter plant cells and interact with intracellular structures and metabolic pathways which may produce toxicity or promote plant growth and development by diverse mechanisms. Depending on their type and concentration, ENMs can have positive or negative effects on photosynthesis, photochemical fluorescence and quantum yield as well as photosynthetic pigments status of the plants. Some studies have shown that ENMs can improve photosynthetic efficiency via increasing chlorophyll content and light absorption and also broadening the spectrum of captured light, suggesting that photosynthesis can be nano-engineered for harnessing more solar energy. Both up- and down-regulation of primary metabolites such as proteins and carbohydrates have been observed following exposure of plants to various ENMs. The potential capacity of ENMs for changing the rate of primary metabolites lies in their close relationship with activation and biosynthesis of the key enzymes. Several classes of secondary metabolites such as phenolics, flavonoids, and alkaloids have been shown to be induced (mostly accompanied by stress-related factors) in plants exposed to different ENMs, highlighting their great potential as elicitors to enhance both quantity and quality of biologically active secondary metabolites. Considering reports on both positive and negative effects of ENMs on plant metabolism, in-depth studies are warranted to figure out the most appropriate ENMs (type, size and optimal concentration) in order to achieve the desirable effect on specific metabolites in a given plant species. In this review, we summarize the studies performed on the impacts of ENMs on biosynthesis of plant primary and secondary metabolites and mention the research gaps that currently exist in this field.
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•Engineered nanomaterials (ENMs) can enter plant cells through different pathways.•They interact with intracellular structures and metabolic pathways.•ENMs can have diverse effects on photosynthesis, photochemical fluorescence and quantum yield.•Several classes of primary and secondary metabolites have been shown to be elicited.
The survival of extreme water deficit stress by tolerant organisms requires a coordinated series of responses, including those at cellular, transcriptional, translational and metabolic levels. Small ...molecules play a pivotal role in creating the proper chemical environment for the preservation of cellular integrity and homeostasis during dehydration. This review surveys recent insights in the importance of primary and specialised metabolites in the response to drying of angiosperms with vegetative desiccation tolerance, i.e. the ability to survive near total loss of water. Important metabolites include sugars such as sucrose, trehalose and raffinose family of oligosaccharides, amino acids and organic acids, as well as antioxidants, representing a common core mechanism of desiccation tolerance. Additional metabolites are discussed in the context of species specificity and adaptation.
Plants defend themselves from most microbial attacks via mechanisms including cell wall fortification, production of antimicrobial compounds, and generation of reactive oxygen species. Successful ...pathogens overcome these host defenses, as well as obtain nutrients from the host. Perturbations of plant metabolism play a central role in determining the outcome of attempted infections. Metabolomic analyses, for example between healthy, newly infected and diseased or resistant plants, have the potential to reveal perturbations to signaling or output pathways with key roles in determining the outcome of a plant-microbe interaction. However, application of this -omic and its tools in plant pathology studies is lagging relative to genomic and transcriptomic methods. Thus, it is imperative to bring the power of metabolomics to bear on the study of plant resistance/susceptibility. This review discusses metabolomics studies that link changes in primary or specialized metabolism to the defense responses of plants against bacterial, fungal, nematode, and viral pathogens. Also examined are cases where metabolomics unveils virulence mechanisms used by pathogens. Finally, how integrating metabolomics with other -omics can advance plant pathology research is discussed.
Plants stimulate microbial enzyme production in the rhizosphere, regulating soil organic matter decomposition and nutrient cycling. The availability of labile organic compounds (i.e. exudates) and ...water is the main prerequisite for such microbial activity and enzyme production, thus shaping the rhizosphere. Root morphology (i.e., root hairs) and exudate composition define the spatial distribution of properties and functions in the rhizosphere. However, the role of root architecture and exudate composition in this spatial self-organization of the rhizosphere remains unknown.
We coupled three in situ imaging approaches: 14C imaging to localize exudates, soil zymography to analyze enzyme activity distribution, and neutron radiography for water fluxes to trace the spatial structure of the rhizosphere of three maize genotypes (wild-type, mutant with defective root-hair prolongation rth3, and mutant with reduced benzoxazinoid content in root exudates bx1). The co-localization of these three soil images revealed the pivotal role of both optimal water content (neutron radiography) and root exudation (14C imaging) for β-glucosidase production by the rhizosphere microbiome and its hydrolytic activity (zymography). Root hairs increased the exudate release and enlarged the spatial extent of increased β-glucosidase activity around the root axis by 35%, leading to a two-fold faster decomposition of 14C exudates compared to the mutant with defective root hairs. In contrast, benzoxazinoids suppressed β-glucosidase activity by 30%, reflecting decreased microbial activity, whereas their absence broadened the rhizosphere. Overall, root hairs in wild-type maize increased microbial activity (i.e. β-glucosidase production), whereas the benzoxazinoids in root exudates suppressed microorganisms.
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•Zymography, 14C imaging, and neutron radiography were coupled to localize rhizosphere processes.•Exudates are released at root tip in wild-type maize, but along the whole root in rth3 and bx1 mutants.•Root hairs enlarged the spatial extent of increased β-glucosidase activity around the root by 35%.•Benzoxazinoids (secondary metabolites) suppressed β-glucosidase activity in the rhizosphere by 30%.•Hotspot co-localization revealed that exudates and water increased β-glucosidase activity.
Seaweeds have received huge interest in recent years given their promising potentialities. Their antioxidant, anti-inflammatory, antitumor, hypolipemic, and anticoagulant effects are among the most ...renowned and studied bioactivities so far, and these effects have been increasingly associated with their content and richness in both primary and secondary metabolites. Although primary metabolites have a pivotal importance such as their content in polysaccharides (fucoidans, agars, carragenans, ulvans, alginates, and laminarin), recent data have shown that the content in some secondary metabolites largely determines the effective bioactive potential of seaweeds. Among these secondary metabolites, phenolic compounds feature prominently. The present review provides the most remarkable insights into seaweed research, specifically addressing its chemical composition, phytopharmacology, and cosmetic applications.
Metabolic regulation is the key mechanism implicated in plants maintaining cell osmotic potential under drought stress. Understanding drought stress tolerance in plants will have a significant impact ...on food security in the face of increasingly harsh climatic conditions. Plant primary and secondary metabolites and metabolic genes are key factors in drought tolerance through their involvement in diverse metabolic pathways. Physio-biochemical and molecular strategies involved in plant tolerance mechanisms could be exploited to increase plant survival under drought stress. This review summarizes the most updated findings on primary and secondary metabolites involved in drought stress. We also examine the application of useful metabolic genes and their molecular responses to drought tolerance in plants and discuss possible strategies to help plants to counteract unfavorable drought periods.
Response surface methodology (RSM) was effectively used for the optimization and modelling of a wide variety of microbial products. This method is a combination of statistical and mathematical ...technique for model construction, assessing the effect of several independent variables and getting optimum values of variables. The purpose of this paper is to review recent research on the utilization of response surface methodology in the fermentation process to optimize microbial activities and products. In addition to discussing the usefulness of using this method, this article also reviews the current information and the hypothetical concepts as well as the main steps for the application of RSM in microbial cultures. Furthermore, this paper attempts to show the recent implementing studies as well as the challenges that may occur on using response surface methodology as an effective technique to develop the performance of industrial microbial strains.
Microalgae have many commercial applications including biofuel production, use in human and animal nutrition, as pharmaceuticals and therapeutic compounds, in beauty-related products and as ...biofertilizers in the agricultural sector. However, more research needs to be directed to reducing production costs in an environmentally friendly way before their commercial potential can be fully realized. This review discusses the current knowledge on the occurrence and physiological roles of phytohormones in microalgae and explores the potential of phytohormone treatments to improve cultivation practices, including increasing lipid content and productivity for biofuel production. Microalgae synthesize a wide array of phytohormones and are able to regulate the levels of active phytohormones. Biosynthetic and conversion pathways share some key components but are more rudimentary compared to vascular plants and are likely to have some unidentified conjugation mechanisms. Phytohormones have a dual function in microalgae. Specific phytohormones are involved in the regulation of the cell cycle and other metabolic processes, influencing biomass and primary metabolite accumulation. They are also involved in responses to abiotic stresses, allowing microalgae to adapt to the prevailing conditions. Phytohormones provide a promising strategy to improve mass culture biotechnology due to their intrinsic role in microalgal growth and survival, increasing lipid productivity and improving their tolerance to more extreme environmental changes. This makes them less susceptible to environmental fluctuations. This improves the productivity of the cultures for biofuel production and would be beneficial in a biorefinery approach. Overall, phytohormones provide an exciting and promising avenue of research to improve microalgae cultivation, taking it a step closer to successful commercialization.
•The potential use of phytohormones to improve microalgae productivity is explored.•Microalgae synthesize an array of phytohormones in response to environmental cues.•Phytohormones stimulate microalgae growth, lipid accumulation and metabolite content.•They also activate antioxidant defense mechanisms in response to stress.•Phytohormones provide a novel strategy to enhance large-scale microalgae cultivation.
•Salinity at 40 mM or 80 mM of show deleterious effects of Egletes viscosa.•SA was able to increase conductance and photosynthesis under salinity.•Both SA and salt change leaf metabolite profile.
...Plant responses to salinity have been long investigated. Nevertheless, how leaf metabolism is affected, and what is the role of salicylic acid (SA) during salt stress remains elusive. Here we evaluated the influence of exogenous SA on the growth, primary and secondary metabolism of the medicinal plant Egletes viscosa under salt stress. Salinity decreased plant biomass, leaf gas exchange, and photosynthetic pigment content. The principal component analysis revealed that both SA and salt altered leaf metabolite profile when analyzed isolated or in combination. Salinity increased several amino acids contents. In contrast, slight changes in the level of organic acids and sugars were observed. Exogenous SA also increased the content of almost all volatile organic compounds (VOCs) identified. The integrative effect of salt and exogenous SA did not reverse the effects of salinity on the plant biomass, nor did it restore VOCs profile. However, SA was able to increase K+ levels, and decrease H2O2 overproduction in salt-stressed plants by increasing key metabolites, which leads to a higher net photosynthetic rate. Taken together, our results suggest that SA increased several metabolites which may contribute to the portioning of Na+ and K+ among roots and shoots alleviating salt stress-induced photosynthesis impairment by modulating key primary and volatile metabolites.
Broccoli sprouts have attracted considerable attention because of their abundant phytochemicals and high selenium accumulation capacity, which reportedly reduce the risks of different cancers and ...cardiovascular diseases. In this study, an untargeted metabolomics approach was developed to investigate the effect of 5 days of treatment with 100 μmol/L selenate on the metabolome of broccoli sprouts. Results showed that the total sulfur content was slightly lower and the total selenium content was significantly higher in the selenate-treated sprouts. The multivariate statistical analyses showed that serine, d-erythronolactone, melezitose and tyrosine were obviously up-regulated, but d-glyceric acid, succinic acid and citric acid were down-regulated after selenate treatment. Moreover, metabolite pathway analyses were used to support the identification of subtle but significant changes among groups of related metabolites that cannot be observed with conventional approaches. Selenate treatment influenced the metabolism of β-alanine and glutathione, as well as the biosynthesis of plant metabolite related to the precursors of glucosinolate. These results could explain why the total glucosinolate decreased after selenate treatment.
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•Effects of Se treatment on GSL metabolism was treated by 100 μmol/L selenate.•The selenate treatment influence the total S content slightly.•Parts of primary metabolites were significantly influenced such as serine, D-erythronolactone.•Selenate treatment mainly influenced the metabolism of β-alanine and glutathione.
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