Effects of Light on Secondary Metabolite Biosynthesis in Medicinal Plants

Exploration and genetic analyses of canopy leaf pigmentation changes in soybean (Glycine max L.): unveiling a novel phenotype

KEY MESSAGE

Pigmentation changes in canopy leaves were first reported, and subsequent genetic analyses identified a major QTL associated with levels of pigmentation changes, suggesting Glyma.06G202300 as a candidate gene. An unexpected reddish-purple pigmentation in upper canopy leaves was discovered during the late reproductive stages in soybean (Glycine max L.) genotypes. Two sensitive genotypes, 'Uram' and PI 96983, exhibited anomalous canopy leaf pigmentation changes (CLPC), while 'Daepung' did not. The objectives of this study were to: (i) characterize the physiological features of pigmented canopy leaves compared with non-pigmented leaves, (ii) evaluate phenotypic variation in a combined recombinant inbred line (RIL) population (N = 169 RILs) under field conditions, and (iii) genetically identify quantitative trait loci (QTL) for CLPC via joint population linkage analysis. Comparison between pigmented and normal leaves revealed different Fv/Fm of photosystem II, hyperspectral reflectance, and cellular properties, suggesting the pigmentation changes occur in response to an undefined abiotic stress. A highly significant QTL was identified on chromosome 6, explaining ~ 62.8% of phenotypic variance. Based on the QTL result, Glyma.06G202300 encoding flavonoid 3'-hydroxylase (F3'H) was identified as a candidate gene. In both Uram and PI 96983, a 1-bp deletion was confirmed in the third exon of Glyma.06G202300 that results in a premature stop codon in both Uram and PI 96983 and a truncated F3'H protein lacking important domains. Additionally, gene expression analyses uncovered significant differences between pigmented and non-pigmented leaves. This is the first report of a novel symptom and an associated major QTL. These results will provide soybean geneticists and breeders with valuable knowledge regarding physiological changes that may affect soybean production. Further studies are required to elucidate the causal environmental stress and the underlying molecular mechanisms.

Phytochemical characterisation of dichloromethane and methanolic extracts of the Ziziphora tenuior leaves and evaluation of their antioxidant and antibacterial activities

Medicinal plants, known for their antibacterial phytocompounds and secondary metabolites, offer promising potential in combating antibiotic-resistant bacteria. This study aimed to perform a phytochemical analysis of the methanol and dichloromethane extracts obtained from Ziziphora tenuior leaves using GC-MS. Furthermore, the antioxidant activity of the extracts was evaluated through the DPPH assay. And, their antibacterial activity was assessed against S. aureus, E. coli, methicillin-resistant S. aureus, and vancomycin-resistant enterococcus (VRE) bacterial strains. Based on the results 90-92% of these extracts consisted of phytocompounds with pharmaceutical properties. Of these, 5-methyl- 2-(1-methylethylidele), Cyclohexanone (Pulegone; C10H16O) comprised the highest percentage of the extracts, constituting 62% of methanolic extract and 81% of dichloromethane extract. Also, both methanolic and dichloromethane extracts showed potent antioxidant activity with IC50 of 277.6 µg/ml and 49.6 µg/ml, respectively. Moreover, these extracts demonstrated considerable antibacterial activity against the tested pathogens, especially against S. aureus and VRE.

Variations in photoperiods and their impact on yield, photosynthesis and secondary metabolite production in basil microgreens

BACKGROUND

The effects of different photoperiods on plant phytochemical synthesis can be improved by adjusting the daily light integral. Photoperiod is one of the most important environmental factors that control growth, plant's internal rhythm and the synthesis of secondary metabolites. Information about the appropriate standard in terms of photoperiod for growing basil microgreens as one of the most important medicinal plants is limited. In this study, the effects of five different photoperiods, 6 (6 h × 3 cycles), 8 (8 h × 2 cycles), 16, 18, and 24 h day- 1 on the yield, photosynthesis and synthesis of secondary metabolites of three cultivars and one genotype of basil microgreens in floating system were evaluated. The purpose of this research was to determine the feasibility of using permanent light in growing basil microgreens and to create the best balance between beneficial secondary metabolites and performance.

RESULTS

The results showed that the effects of photoperiod and cultivar on all investigated traits and their interaction on photosynthetic pigments, antioxidant capacity, total phenolic compounds, proline content and net photosynthesis rate were significantly different at the 1% level. The highest levels of vitamin C, flavonoids, anthocyanins, yield and antioxidant potential composite index (APCI) were obtained under the 24-h photoperiod. The highest antioxidant capacity was obtained for the Kapoor cultivar, and the highest total phenolic compound and proline contents were measured for the Ablagh genotype under a 24-h photoperiod. The highest yield (4.36 kg m- 2) and APCI (70.44) were obtained for the Ablagh genotype. The highest nitrate content was obtained with a photoperiod of 18 h for the Kapoor cultivar. The highest net photosynthesis rate was related to the Violeto cultivar under a 24-hour photoperiod (7.89 μmol CO2 m- 2 s- 1). Antioxidant capacity and flavonoids had a positive correlation with phenolic compounds and vitamin C. Yield had a positive correlation with antioxidant capacity, flavonoids, vitamin C, APCI, and proline.

CONCLUSIONS

Under continuous light conditions, basil microgreens resistance to light stress by increasing the synthesis of secondary metabolites and the increase of these biochemical compounds made basil microgreens increase their performance along with the increase of these health-promoting compounds. The best balance between antioxidant compounds and performance was achieved in continuous red + blue light. Based on these results, the use of continuous artificial LED lighting, due to the increase in plant biochemical with antioxidant properties and yield, can be a suitable strategy for growing basil microgreens in floating systems.

Analysis of lettuce transcriptome reveals the mechanism of different light/dark cycle in promoting the growth and quality

Light/dark (L/D) cycle plays a crucial role in controlling the production and quality of vegetables. However, the mechanism of L/D cycle on vegetable growth and quality is scarce studied. To investigate the impact of L/D cycle on lettuce growth and quality, we designed three diel scenarios, including 16 hours of light and 8 hours of darkness (L16/D8), 12 hours of light and 6 hours of darkness (L12/D6), and 8 hours of light and 4 hours of darkness (L8/D4). By phenotypic analysis, we found that lettuce grew taller under the L8/D4 scenario than under L16/D8 light cycle scenarios. The physiological indexes showed that the lettuce leaves grown in the L8/D4 scenario exhibited greater enhancements in the levels of soluble protein, soluble sugar, and carotenoid content compared to the other scenarios. By comparing the expression levels under different diel scenarios (L16/D8 vs L12/D6, L16/D8 vs L8/D4, and L12/D6 vs L8/D4), we identified 7,209 differentially expressed genes (DEGs). Additionally, 3 gene modules that were closely related to L/D cycle of lettuce were selected by WGCNA analysis. The eigengenes of three gene modules were enriched in plant hormone signal transduction, sphingolipid metabolism, and nucleocytoplasmic transport pathways. Through network analysis, we identified six hub genes (CIP1, SCL34, ROPGEF1, ACD6, CcmB, and Rps4) in the three gene modules, which were dominant in plant circadian rhythms and greatly affected lettuce growth. qRT-PCR analysis confirmed the diurnal response patterns of the 6 hub genes in different treatments were significant. This study intensively enhanced our comprehension of the L/D cycle in the growth morphology, nutritional quality, and metabolic pathways of lettuce.

Transcriptome and metabolome analysis reveals mechanism of light intensity modulating iridoid biosynthesis in Gentiana macrophylla Pall

Light intensity is a key factor affecting the synthesis of secondary metabolites in plants. However, the response mechanisms of metabolites and genes in Gentiana macrophylla under different light intensities have not been determined. In the present study, G. macrophylla seedlings were treated with LED light intensities of 15 µmol/m2/s (low light, LL), 90 µmol/m2/s (medium light, ML), and 200 µmol/m2/s (high light, HL), and leaves were collected on the 5th day for further investigation. A total of 2162 metabolites were detected, in which, the most abundant metabolites were identified as flavonoids, carbohydrates, terpenoids and amino acids. A total of 3313 and 613 differentially expressed genes (DEGs) were identified in the LL and HL groups compared with the ML group, respectively, mainly enriched in KEGG pathways such as carotenoid biosynthesis, carbon metabolism, glycolysis/gluconeogenesis, amino acids biosynthesis, plant MAPK pathway and plant hormone signaling. Besides, the transcription factors of GmMYB5 and GmbHLH20 were determined to be significantly correlated with loganic acid biosynthesis; the expression of photosystem-related enzyme genes was altered under different light intensities, regulating the expression of enzyme genes involved in the carotenoid, chlorophyll, glycolysis and amino acids pathway, then affecting their metabolic biosynthesis. As a result, low light inhibited photosynthesis, delayed glycolysis, thus, increased certain amino acids and decreased loganic acid production, while high light got an opposite trend. Our research contributed significantly to understand the molecular mechanism of light intensity in controlling metabolic accumulation in G. macrophylla.

Photoperiod-Dependent Nutrient Accumulation in Rice Cultivated in Plant Factories: A Comparative Metabolomic Analysis

Plant factories offer a promising solution to some of the challenges facing traditional agriculture, allowing for year-round rapid production of plant-derived foods. However, the effects of conditions in plant factories on metabolic nutrients remain to be explored. In this study, we used three rice accessions (KongYu131, HuangHuaZhan, and Kam Sweet Rice) as objectives, which were planted in a plant factory with strict photoperiods that are long-day (12 h light/12 h dark) or short-day (8 h light/16 h dark). A total of 438 metabolites were detected in the harvested rice grains. The difference in photoperiod leads to a different accumulation of metabolites in rice grains. Most metabolites accumulated significantly higher levels under the short-day condition than the long-day condition. Differentially accumulated metabolites were enriched in the amino acids and vitamin B6 pathway. Asparagine, pyridoxamine, and pyridoxine are key metabolites that accumulate at higher levels in rice grains harvested from the short-day photoperiod. This study reveals the photoperiod-dependent metabolomic differences in rice cultivated in plant factories, especially the metabolic profiling of taste- and nutrition-related compounds.

Ménage à trois: light, terpenoids, and quality of plants

In controlled environment agriculture (CEA), light is used to impact terpenoid production and improve plant quality. In this review we discuss various aspects of light as important regulators of terpenoid production in different plant organs. Spectral quality primarily modifies terpenoid profiles, while intensity and photoperiod influence abundances. The central regulator of light signal transduction elongated hypocotyl 5 (HY5) controls transcriptional regulation of terpenoids under UV, red (R), and blue (B) light. The larger the fraction of R and green (G) light, the more beneficial the effect on monoterpenoid and sesquiterpenoid biosynthesis, and such an effect may depend on the presence of B light. A large fraction of R light is mostly detrimental to tetraterpenoid production. We conclude that light is a promising tool to steer terpenoid production and potentially tailor the quality of plants.

Prediction of Historical, Current, and Future Configuration of Tibetan Medicinal Herb Gymnadenia orchidis Based on the Optimized MaxEnt in the Qinghai-Tibet Plateau

Climate change plays a pivotal role in shaping the shifting patterns of plant distribution, and gaining insights into how medicinal plants in the plateau region adapt to climate change will be instrumental in safeguarding the rich biodiversity of the highlands. Gymnosia orchidis Lindl. (G. orchidis) is a valuable Tibetan medicinal resource with significant medicinal, ecological, and economic value. However, the growth of G. orchidis is severely constrained by stringent natural conditions, leading to a drastic decline in its resources. Therefore, it is crucial to study the suitable habitat areas of G. orchidis to facilitate future artificial cultivation and maintain ecological balance. In this study, we investigated the suitable zones of G. orchidis based on 79 occurrence points in the Qinghai-Tibet Plateau (QTP) and 23 major environmental variables, including climate, topography, and soil type. We employed the Maximum Entropy model (MaxEnt) to simulate and predict the spatial distribution and configuration changes in G. orchidis during different time periods, including the last interglacial (LIG), the Last Glacial Maximum (LGM), the Mid-Holocene (MH), the present, and future scenarios (2041-2060 and 2061-2080) under three different climate scenarios (SSP126, SSP370, and SSP585). Our results indicated that annual precipitation (Bio12, 613-2466 mm) and mean temperature of the coldest quarter (Bio11, -5.8-8.5 °C) were the primary factors influencing the suitable habitat of G. orchidis, with a cumulative contribution of 78.5%. The precipitation and temperature during the driest season had the most significant overall impact. Under current climate conditions, the suitable areas of G. orchidis covered approximately 63.72 × 104/km2, encompassing Yunnan, Gansu, Sichuan, and parts of Xizang provinces, with the highest suitability observed in the Hengduan, Yunlin, and Himalayan mountain regions. In the past, the suitable area of G. orchidis experienced significant changes during the Mid-Holocene, including variations in the total area and centroid migration direction. In future scenarios, the suitable habitat of G. orchidis is projected to expand significantly under SSP370 (30.33-46.19%), followed by SSP585 (1.41-22.3%), while contraction is expected under SSP126. Moreover, the centroids of suitable areas exhibited multidirectional movement, with the most extensive displacement observed under SSP585 (100.38 km2). This study provides a theoretical foundation for the conservation of biodiversity and endangered medicinal plants in the QTP.

A study of volatiles of young citrus fruits from four areas based on GC-MS and flash GC e-nose combined with multivariate algorithms

The present study has successfully established a scientific and precise approach for distinguishing the geographical origins of young citrus fruits (Qingpi) from four primary production regions in China, using gas chromatography-mass spectrometry (GC-MS) and flash gas chromatography electronic nose (flash GC e-nose) to analyze the volatile composition and odor characteristics. Through the application of chemometric analysis, a clear differentiation among Qingpi samples was established using GC-MS. Additionally, the application of flash GC e-nose facilitated the extraction of flavor information, which enabled the discrimination of geographical origins. Several flavor components were identified as significant factors for origin certification. Furthermore, two pattern recognition algorithms were employed to achieve high accuracy in regional identification. The results of this investigation demonstrate that the amalgamation of multivariate chemometrics and algorithms can proficiently discern the sources of those young citrus fruits. The findings of this research can provide a reference for the assessment of quality control in food and other agricultural commodities in the times ahead.

Integrated Metabolomics Approach Reveals the Dynamic Variations of Metabolites and Bioactivities in Paeonia ostii 'Feng Dan' Leaves during Development

Paeonia ostii 'Feng Dan' is widely cultivated in China for its ornamental, medicinal, and edible properties. The whole plant of tree peony is rich in bioactive substances, while the comprehensive understanding of metabolites in the leaves is limited. In this study, an untargeted metabolomics strategy based on UPLC-ESI-TOF-MS was conducted to analyze the dynamic variations of bioactive metabolites in P. ostii 'Feng Dan' leaves during development. A total of 321 metabolites were rapidly annotated based on the GNPS platform, in-house database, and publications. To accurately quantify the selected metabolites, a targeted method of HPLC-ESI-QQQ-MS was used. Albiflorin, paeoniflorin, pentagalloylglucose, luteolin 7-glucoside, and benzoylpaeoniflorin were recognized as the dominant bioactive compounds with significant content variations during leaf development. Metabolite variations during the development of P. ostii 'Feng Dan' leaves are greatly attributed to the variations in antioxidant activities. Among all tested bacteria, the leaf extract exhibited exceptional inhibitory effects against Streptococcus hemolytis-β. This research firstly provides new insights into tree peony leaves during development. The stages of S1-S2 may be the most promising harvesting time for potential use in food or pharmaceutical purposes.

AaABI5 transcription factor mediates light and abscisic acid signaling to promote anti-malarial drug artemisinin biosynthesis in Artemisia annua

Artemisia annua, a member of the Asteraceae family, remains the primary source of artemisinin. However, the artemisinin content in the existing varieties of this plant is very low. In this study, we found that the environmental factors light and phytohormone abscisic acid (ABA) could synergistically promote the expression of artemisinin biosynthetic genes. Notably, the increased expression levels of those genes regulated by ABA depended on light. Gene expression analysis found that AaABI5, a transcription factor belonging to the basic leucine zipper (bZIP) family, was inducible by the light and ABA treatment. Analysis of AaABI5-overexpressing and -suppressing lines suggested that AaABI5 could enhance artemisinin biosynthesis and activate the expression of four core biosynthetic genes. In addition, the key regulator of light-induced artemisinin biosynthesis, AaHY5, could bind to the promoter of AaABI5 and activate its expression. In conclusion, our results demonstrated that AaABI5 acts as an important molecular junction for the synergistic promotion of artemisinin biosynthesis by light and ABA signals, which provides a candidate gene for developing new germplasms of high-quality A. annua.

Altitudinal Variation on Metabolites, Elements, and Antioxidant Activities of Medicinal Plant Asarum

Asarum (Asarum sieboldii Miq. f. seoulense (Nakai) C. Y. Cheng et C. S. Yang) is a medicinal plant that contains asarinin and sesamin, which possess extensive medicinal value. The adaptation and distribution of Asarum's plant growth are significantly affected by altitude. Although most studies on Asarum have concentrated on its pharmacological activities, little is known about its growth and metabolites with respect to altitude. In this study, the physiology, ionomics, and metabolomics were investigated and conducted on the leaves and roots of Asarum along an altitude gradient, and the content of its medicinal components was determined. The results showed that soil pH and temperature both decreased along the altitude, which restricts the growth of Asarum. The accumulation of TOC, Cu, Mg, and other mineral elements enhanced the photosynthetic capacity and leaf plasticity of Asarum in high-altitude areas. A metabolomics analysis revealed that, at high altitude, nitrogen metabolism in leaves was enhanced, while carbon metabolism in roots was enhanced. Furthermore, the metabolic pathways of some phenolic substances, including syringic acid, vanillic acid, and ferulic acid, were altered to enhance the metabolism of organic acids. The study uncovered the growth and metabolic responses of Asarum to varying altitudes, providing a theoretical foundation for the utilization and cultivation of Asarum.

Light spectra manipulation stimulates growth, specialized metabolites and nutritional quality in Anethum graveolens

Light-Emitting Diodes (LED) play a major role in manipulating light spectra that helps in regulating the growth and specialized metabolite synthesis relevant to the plant defence system. In this study, we assessed photosynthetic performance, phytonutrients, and anatomical variations of an aromatic herb Anethum graveolens (also known as dill), grown under various combinations of LED lights viz. red (100R:0B), red:blue (50R:50B); blue (0R:100B) and warm white (WW, served as control). Exposure to 0R:100B LED lights led to the tallest stem height, whereas, the number of leaves were highest under 50R:50B LED lights. The photosynthetic performance was observed to be highest under 50R:50B LED lights. HPLC analysis revealed chlorogenic acid and rosmarinic acid as the major phenolic compounds accumulated under different spectral irradiations. The highest chlorogenic acid content was observed in 50R:50B LED treated dill plants, while 100R:0B light showed the highest accumulation of rosmarinic acid. Dill plants grown under 50R:50B light displayed a relatively higher content of volatile compounds including, myristicin (phenylpropene), psi-limonene, and α-phellandrene (monoterpenoids). Expression analyses of candidate genes of phenylpropanoid and monoterpenoid biosynthetic pathways showed good correlations with the enhanced phenolic compounds and monoterpenes detected under appropriate light treatments. Further, the stem anatomy revealed higher vascularization under the influence of 0R:100B LED lights, whereas, intense histochemical localization of specialized metabolites could be correlated with enhanced accumulation of phenolic compounds and terpenoids observed in this study. Taken together, these studies suggest that proper combinations of blue and red spectra of light could play important role to augment the growth and phytochemical characteristics of dill, thus improving its value addition in the food industry.

Light regulation of the biosynthesis of phenolics, terpenoids, and alkaloids in plants

Biosynthesis of specialized metabolites (SM), including phenolics, terpenoids, and alkaloids, is stimulated by many environmental factors including light. In recent years, significant progress has been made in understanding the regulatory mechanisms involved in light-stimulated SM biosynthesis at the transcriptional, posttranscriptional, and posttranslational levels of regulation. While several excellent recent reviews have primarily focused on the impacts of general environmental factors, including light, on biosynthesis of an individual class of SM, here we highlight the regulation of three major SM biosynthesis pathways by light-responsive gene expression, microRNA regulation, and posttranslational modification of regulatory proteins. In addition, we present our future perspectives on this topic.

Factors Affecting the Bioproduction of Resveratrol by Grapevine Cell Cultures under Elicitation

Here we present a study of the characterization and optimization of the production of trans-Resveratrol (t-R) in grape (Vitis vinifera cv. Gamay) cell cultures elicited with methyl jasmonate (MeJA) and dimethyl-β-cyclodextrin (DIMEB). The aim of this study was to determine the influence of a number of factors of the grapevine cell culture on t-R production level in 250 mL shaken flasks that would enable the better control of this bioproduction system when it is upscaled to a 2 L stirred bioreactor. The factors included the optimal growth phase for elicitation, the concentration of elicitors and of biomass, the order of addition of elicitors, and the illumination regime and ageing of cells. We found out that the optimal biomass density for the production of t-R was 19% (w/v) with an optimal ratio of 0.5 g DIMEB/g biomass. The most productive concentrations of the elicitors tested were 50 mM DIMEB and 100 µM MeJA, reaching maximum values of 4.18 mg·mL-1 and 16.3 mg·g biomass-1 of t-R concentration and specific production, respectively. We found that the order of elicitor addition matters since, as compared with the simultaneous addition of both elicitors, the addition of MeJA 48 h before DIMEB results in ca. 40% less t-R production, whilst there is no significant difference when MeJA is added 48 h after DIMEB. Upon upscaling, the better conditions tested for t-R production were aeration at 1.7 vol/vol/min without agitation, 24 °C, and 30 g·L-1 sucrose, achieving production rates similar to those obtained in shaken flasks.

Unlocking secrets of nature's chemists: Potential of CRISPR/Cas-based tools in plant metabolic engineering for customized nutraceutical and medicinal profiles

Plant species have evolved diverse metabolic pathways to effectively respond to internal and external signals throughout their life cycle, allowing adaptation to their sessile and phototropic nature. These pathways selectively activate specific metabolic processes, producing plant secondary metabolites (PSMs) governed by genetic and environmental factors. Humans have utilized PSM-enriched plant sources for millennia in medicine and nutraceuticals. Recent technological advances have significantly contributed to discovering metabolic pathways and related genes involved in the biosynthesis of specific PSM in different food crops and medicinal plants. Consequently, there is a growing demand for plant materials rich in nutrients and bioactive compounds, marketed as "superfoods". To meet the industrial demand for superfoods and therapeutic PSMs, modern methods such as system biology, omics, synthetic biology, and genome editing (GE) play a crucial role in identifying the molecular players, limiting steps, and regulatory circuitry involved in PSM production. Among these methods, clustered regularly interspaced short palindromic repeats-CRISPR associated protein (CRISPR/Cas) is the most widely used system for plant GE due to its simple design, flexibility, precision, and multiplexing capabilities. Utilizing the CRISPR-based toolbox for metabolic engineering (ME) offers an ideal solution for developing plants with tailored preventive (nutraceuticals) and curative (therapeutic) metabolic profiles in an ecofriendly way. This review discusses recent advances in understanding the multifactorial regulation of metabolic pathways, the application of CRISPR-based tools for plant ME, and the potential research areas for enhancing plant metabolic profiles.

Succession of endophytic fungi and rhizosphere soil fungi and their correlation with secondary metabolites in Fagopyrum dibotrys

Golden buckwheat (Fagopyrum dibotrys, also known as F. acutatum) is a traditional edible herbal medicinal plant with a large number of secondary metabolites and is considered to be a source of therapeutic compounds. Different ecological environments have a significant impact on their compound content and medicinal effects. However, little is known about the interactions between soil physicochemical properties, the rhizosphere, endophytic fungal communities, and secondary metabolites in F. dibotrys. In this study, the rhizosphere soil and endophytic fungal communities of F. dibotrys in five different ecological regions in China were identified based on high-throughput sequencing methods. The correlations between soil physicochemical properties, active components (total saponins, total flavonoids, proanthocyanidin, and epicatechin), and endophytic and rhizosphere soil fungi of F. dibotrys were analyzed. The results showed that soil pH, soil N, OM, and P were significantly correlated with the active components of F. dibotrys. Among them, epicatechin, proanthocyanidin, and total saponins were significantly positively correlated with soil pH, while proanthocyanidin content was significantly positively correlated with STN, SAN, and OM in soil, and total flavone content was significantly positively correlated with P in soil. In soil microbes, Mortierella, Trechispora, Exophiala, Ascomycota_unclassified, Auricularia, Plectosphaerella, Mycena, Fungi_unclassified, Agaricomycetes_unclassified, Coprinellus, and Pseudaleuria were significantly related to key secondary metabolites of F. dibotrys. Diaporthe and Meripilaceae_unclassified were significantly related to key secondary metabolites in the rhizome. This study presents a new opportunity to deeply understand soil-plant-fungal symbioses and secondary metabolites in F. dibotrys, as well as provides a scientific basis for using biological fertilization strategies to improve the quality of F. dibotrys.

Investigating the Physiological and Molecular Responses of Solanum lycopersicum hp Mutants to Light of Different Quality for Biotechnological Applications

The effect of the light of different spectral compositions, white fluorescent light (WFL), red light (RL, 660 nm), blue light (BL, 450 nm), green light (GL, 525 nm), and white LED light (WL, 450 + 580 nm), on the physiological parameters of Solanum lycopersicum 3005 hp-2 (defective for a DET1 gene) and 4012 hp-1w; 3538 hp-1; 0279 hp-1.2 (defective for a DDB1a gene) photomorphogenetic mutants was studied. The parameters of the primary photochemical processes of photosynthesis, photosynthetic and transpiration rates, the antioxidant capacity of low-molecular weight antioxidants, the content of the total phenolic compounds, including flavonoids, and the expression of the genes involved in light signaling and biosynthesis of secondary metabolites were determined. Under BL, the 3005 hp-2 mutant showed the highest nonenzymatic antioxidant activity, which occurred to a greater extent due to the increase in flavonoid content. At the same time, under BL, the number of secretory trichomes on the surface of the leaves of all mutants increased equally. This suggests the accumulation of flavonoids inside leaf cells rather than in trichomes on the leaf surface. The data obtained indicate the possibility of using the hp-2 mutant for biotechnology to increase its nutritional value by enhancing the content of flavonoids and other antioxidants by modulating the spectral composition of light.

Phenolic Acids and Amaryllidaceae Alkaloids Profiles in Leucojum aestivum L. In Vitro Plants Grown under Different Light Conditions

Light-emitting diodes (LEDs) have emerged as efficient light sources for promoting in vitro plant growth and primary and secondary metabolite biosynthesis. This study investigated the effects of blue, red, and white-red LED lights on plant biomass growth, photosynthetic pigments, soluble sugars, phenolic compounds, the production of Amaryllidaceae alkaloids, and the activities of antioxidant enzymes in Leucojum aestivum L. cultures. A white fluorescent light was used as a control. The plants that were grown under white-red and red light showed the highest fresh biomass increments. The blue light stimulated chlorophyll a, carotenoid, and flavonoid production. The white-red and blue lights were favourable for phenolic acid biosynthesis. Chlorogenic, p-hydroxybenzoic, caffeic, syringic, p-coumaric, ferulic, sinapic, and benzoic acids were identified in plant materials, with ferulic acid dominating. The blue light had a significant beneficial effect both on galanthamine (4.67 µg/g of dry weight (DW)) and lycorine (115 µg/g DW) biosynthesis. Red light treatment increased catalase and superoxide dismutase activities, and high catalase activity was also observed in plants treated with white-red and blue light. This is the first report to provide evidence of the effects of LED light on the biosynthesis of phenolic acid and Amaryllidaceae alkaloids in L. aestivum cultures, which is of pharmacological importance and can propose new strategies for their production.

Integration of high-throughput omics technologies in medicinal plant research: The new era of natural drug discovery

Medicinal plants are natural sources to unravel novel bioactive compounds to satisfy human pharmacological potentials. The world's demand for herbal medicines is increasing year by year; however, large-scale production of medicinal plants and their derivatives is still limited. The rapid development of modern technology has stimulated multi-omics research in medicinal plants, leading to a series of breakthroughs on key genes, metabolites, enzymes involved in biosynthesis and regulation of active compounds. Here, we summarize the latest research progress on the molecular intricacy of medicinal plants, including the comparison of genomics to demonstrate variation and evolution among species, the application of transcriptomics, proteomics and metabolomics to explore dynamic changes of molecular compounds, and the utilization of potential resources for natural drug discovery. These multi-omics research provide the theoretical basis for environmental adaptation of medicinal plants and allow us to understand the chemical diversity and composition of bioactive compounds. Many medicinal herbs' phytochemical constituents and their potential health benefits are not fully explored. Given their large diversity and global distribution as well as the impacts of growth duration and environmental factors on bioactive phytochemicals in medicinal plants, it is crucial to emphasize the research needs of using multi-omics technologies to address basic and applied problems in medicinal plants to aid in developing new and improved medicinal plant resources and discovering novel medicinal ingredients.

Evaluation of antibacterial, antioxidant, and anti-inflammatory properties of GC/MS characterized methanol leaf extract of Terminalia superba (Combretaceae, Engl. & Diels)

Background

Terminalia superba is a well-known medicinal plant used in folk medicine for the management of various diseases and swelling. Validation of its efficacy in standardized scientific models is lacking. This gap needs to be filled as a way of enhancing modern drug discovery. The aim is to evaluate the antibacterial, antioxidant, and anti-inflammatory properties of T. superba in known and established models. Also, to establish and possibly correlate the established activity with the phytochemicals identified using GC/MS and qualitative methods.

Results

The result showed a dose-dependent percentage inhibition of DPPH, HO•, and Fe3+ reducing activity. The antibacterial activity showed dose-dependent significant (p < 0.05) inhibition against all the organisms used. The anti-inflammatory activity of METS was confirmed in the carrageenan model with significant (p < 0.05) inhibition of paw volume when compared to control while significantly decreasing (p < 0.05) weight of xylene-induced ear. For instance, after 6 h, there was  a reduction of 42%, 33%, and 22% for diclofenac, 200 mg, and 100 mg, respectively, as against 4% in control. The significant (p < 0.05) increase in MDA was attenuated by the treatment with METS dose dependently. Phytochemical assay and GC/MS characterization showed that alkaloids, saponins, phenols, quinone, tannins, coumarins, proteins, flavonoids, and amino acids were dominant with fatty acids accounting for 53%. Others are esters (23%), organic compounds (12%), alkanes (9%), and carboxylic acids (3%).

Conclusions

T. superba possesses antioxidant, antibacterial, and anti-inflammatory properties which are believed to arise from the secondary metabolites observed in the GC–MS characterization.

Graphical Abstract

Transcriptome analysis provides insights into light condition effect on paclitaxel biosynthesis in yew saplings

BACKGROUND

Taxus is a rare gymnosperm plant that is the sole producer of the anticancer drug paclitaxel. The growth and development of Taxus is affected by environmental factors such as light. However, little is known about how light conditions affect growth and metabolic processes, especially paclitaxel biosynthesis.

RESULTS

In this study, we applied three different light conditions to Taxus chinensis young saplings and investigated the physiological response and gene expression. Our observations showed that exposure to high light led to oxidative stress, caused photoinhibition, and damaged the photosynthetic systems in T. chinensis. The paclitaxel content in T. chinensis leaves was significantly decreased after the light intensity increased. Transcriptomic analysis revealed that numerous genes involved in paclitaxel biosynthesis and phenylpropanoid metabolic pathways were downregulated under high light. We also analyzed the expression of JA signaling genes, bHLH, MYB, AP2/ERF transcription factors, and the CYP450 families that are potentially related to paclitaxel biosynthesis. We found that several CYP450s, MYB and AP2/ERF genes were induced by high light. These genes may play an important role in tolerance to excessive light or heat stress in T. chinensis.

CONCLUSIONS

Our study elucidates the molecular mechanism of the effects of light conditions on the growth and development of T. chinensis and paclitaxel biosynthesis, thus facilitating the artificial regeneration of Taxus and enhancing paclitaxel production.

Antioxidant, Antimicrobial, Cytotoxicity, and Larvicidal Activities of Selected Synthetic Bis-Chalcones

Plants are known to have numerous phytochemicals and other secondary metabolites with numerous pharmacological and biological properties. Among the various compounds, polyphenols, flavonoids, anthocyanins, alkaloids, and terpenoids are the predominant ones that have been explored for their biological potential. Among these, chalcones and bis-chalcones are less explored for their biological potential under in vitro experiments, cell culture models, and animal studies. In the present study, we evaluated six synthetic bis-chalcones that were different in terms of their aromatic cores, functional group substitution, and position of substitutions. The results indicated a strong antioxidant property in terms of DPPH and ABTS radical-scavenging potentials and ferric-reducing properties. In addition, compounds 1, 2, and 4 exhibited strong antibacterial activities against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Salmonella enteritidis. The disc diffusion assay values were indicative of the antibacterial properties of these compounds. Overall, the study indicated the antioxidant and antimicrobial properties of the compounds. Our preliminary studies point to the potential of this class of compounds for further in vivo investigation.

Integrated metabolomic and transcriptomic analyses reveal molecular response of anthocyanins biosynthesis in perilla to light intensity

The perilla anthocyanins have important medicinal and ornamental value, and their contents are significantly affected by light intensity. In view of their molecular mechanisms were not well understood, we integrated the metabolomic and transcriptomic analyses of the light-sensitive perilla variety under different light intensity. The perilla leave color were obviously affected under different treatments. Totally 140 flavonoid metabolites and 2461 genes showed steady change, among which 60 flavonoid metabolites were increased accumulation and 983 genes were upregulated expression under elevated light intensity treatment. Light treatment prominently affected the expression of genes involved in the main anthocyanin metabolites accumulation in perilla leaves. Using WGCNA analysis, we identified 4 key genes in anthocyanin biosynthesis pathway (CHI, DFR, and ANS) and 147 transcription factors (MYB, bHLH, bZIP, ERF, and NAC) involved in malonylshisonin biosynthesis. Among them, 6 MYBs and 4 bZIPs were predicted to play important roles in light regulation of malonylshisonin biosynthesis based on phylogenetic construction, correlation analysis, cis-acting element identification and qPCR verification. The identified key genes and regulatory factors will help us to understand the potential mechanism of photo-regulated anthocyanin accumulation in perilla.

Acclimation Strategy of Masson Pine (Pinus massoniana) by Limiting Flavonoid and Terpenoid Production under Low Light and Drought

Low light and drought often limit the growth and performance of Masson pines (Pinus massoniana) in the subtropical forest ecosystem of China. We speculated that stress-induced defensive secondary metabolites, such as flavonoids and terpenoids, might influence the growth of Masson pines, considering the existence of tradeoffs between growth and defense. However, the mechanisms of Masson pines responsive to low light and drought at the levels of these two metabolites remain unclear. In the present work, the compositions of flavonoids and terpenoids, as well as their biosynthetic pathways, were revealed through metabolome and transcriptome analyses, respectively, coupled with a study on carbon allocation using a ¹³CO₂-pulse-labeling experiment in two-year-old seedlings under low light (LL), drought (DR), and their combined stress (DL) compared to a control (CK). A total of 35 flavonoids and derivatives (LL vs. CK: 18; DR vs. CK: 20; and DL vs. CK: 18), as well as 29 terpenoids and derivatives (LL vs. CK: 23; DR vs. CK: 13; and DL vs. CK: 7), were differentially identified in the leaves. Surprisingly, most of them were decreased under all three stress regimes. At the transcriptomic level, most or all of the detected DEGs (differentially expressed genes) involved in the biosynthetic pathways of flavonoids and terpenoids were downregulated in phloem and xylem under stress treatments. This indicated that stress treatments limited the production of flavonoids and terpenoids. The reduction in the ¹³C allocation to stems might suggest that it is necessary for maintaining the growth of Masson pine seedlings at the whole-plant level by attenuating energetic resources to the biosynthetic pathways of flavonoids and terpenoids when facing the occurrence of adverse environments. Our results provide new insight into understanding the acclimation strategy of Masson pines or other conifers in adverse environments.

Effects of Laser Irradiation at 488, 514, 532, 552, 660, and 785 nm on the Aqueous Extracts of Plantago lanceolata L.: A Comparison on Chemical Content, Antioxidant Activity and Caco-2 Viability

In this study, six laser radiation (488 nm/40 mW, 514 nm/15 mW, 532 nm/20 mW, 552 nm/15 mW, 660 nm/ 75 mW, and at 785 nm/70 mW) were tested on the aqueous extracts of leaves of Plantago lanceolata L. to compare extraction efficacy and antioxidant and cell viability effects in vitro. Briefly, in comparison with the control extract, laser extracts at 488, 514, 532, and 552 nm revealed small acquisitions of total extractible compounds in samples (up to 6.52%; laser extracts at 488 and 532 nm also revealed minerals and micro-elements increases (up to 6.49%); the most prominent results were obtained upon Fe (up to 38%, 488 nm), Cr (up to 307%, 660 nm), and Zn (up to 465%, 532 nm). Laser extracts at 488, 514, 552, and 785 nm proved more intense antioxidant capacity than the control sample, while laser extract at 660 nm indicated clear pro-oxidant effects. Caco-2 cells study indicated stimulatory activity for the extracts at 488 nm, no effects at 532 nm, and the decrease of the cell viability in the case of extracts at 660 nm respectively. Further studies are necessary to understand the pro-oxidant effects observed in the case of extracts exposed to laser radiation at 660 nm.

Environmental and Genetic Factors Involved in Plant Protection-Associated Secondary Metabolite Biosynthesis Pathways

Plant specialized metabolites (PSMs) play essential roles in the adaptation to harsh environments and function in plant defense responses. PSMs act as key components of defense-related signaling pathways and trigger the extensive expression of defense-related genes. In addition, PSMs serve as antioxidants, participating in the scavenging of rapidly rising reactive oxygen species, and as chelators, participating in the chelation of toxins under stress conditions. PSMs include nitrogen-containing chemical compounds, terpenoids/isoprenoids, and phenolics. Each category of secondary metabolites has a specific biosynthetic pathway, including precursors, intermediates, and end products. The basic biosynthetic pathways of representative PSMs are summarized, providing potential target enzymes of stress-mediated regulation and responses. Multiple metabolic pathways share the same origin, and the common enzymes are frequently to be the targets of metabolic regulation. Most biosynthetic pathways are controlled by different environmental and genetic factors. Here, we summarized the effects of environmental factors, including abiotic and biotic stresses, on PSM biosynthesis in various plants. We also discuss the positive and negative transcription factors involved in various PSM biosynthetic pathways. The potential target genes of the stress-related transcription factors were also summarized. We further found that the downstream targets of these Transcription factors (TFs) are frequently enriched in the synthesis pathway of precursors, suggesting an effective role of precursors in enhancing of terminal products. The present review provides valuable insights regarding screening targets and regulators involved in PSM-mediated plant protection in non-model plants.