Plant Secondary Metabolism Research Articles

Identification of R2R3-MYB family in blueberry and its potential involvement of anthocyanin biosynthesis in fruits

BackgroundBlueberries (Vaccinium corymbosum) are regarded as “superfoods” attributed to large amounts of anthocyanins, a group of flavonoid metabolites, which provide pigmentation in plant and beneficial effects for human health. MYB transcription factor is one of vital components in the regulation of plant secondary metabolism, which occupies a dominant position in the regulatory network of anthocyanin biosynthesis. However, the role of MYB family in blueberry responding to anthocyanin biosynthesis remains elusive.ResultsIn this study, we conducted a comprehensive analysis of VcMYBs in blueberry based on the genome data, including phylogenetic relationship, conserved motifs, identification of differentially expressed MYB genes during fruit development and their expression profiling, etc. A total of 437 unique MYB sequences with two SANT domains were identified in blueberry, which were divided into 3 phylogenetic trees. Noticeably, there are many trigenic and tetragenic VcMYBs pairs with more than 95% identity to each other. Meanwhile, the transcript accumulations of VcMYBs were surveyed underlying blueberry fruit development, and they showed diverse expression patterns, suggesting various functional roles in fruit ripening. More importantly, distinct transcript profiles between skin and pulp of ripe fruit were observed for several VcMYBs, such as VcMYB437, implying the potential roles in anthocyanin biosynthesis.ConclusionsTotally, 437 VcMYBs were identified and characterized. Subsequently, their transcriptional patterns were explored during fruit development and fruit tissues (skin and pulp) closely related to anthocyanin biosynthesis. These genome-wide data and findings will contribute to demonstrating the functional roles of VcMYBs and their regulatory mechanisms for anthocyanins production and accumulation in blueberry in the future study.

Use of Elicitors and Beneficial Bacteria to Induce and Prime the Stilbene Phytoalexin Response: Applications to Grapevine Disease Resistance

Phytoalexins are naturally occurring molecules with antimicrobial activity deriving from the secondary metabolism of plants; they are synthesized in response to physical agents or stresses and phytopathogenic agents (fungi, bacteria and viruses), as well as numerous chemical compounds and biological control agents. Among these, grapevine phytoalexins, which belong to the chemical group of stilbenes, exhibit biocidal activity against a large number and variety of plant pathogens. It is important to investigate whether induction of stilbene phytoalexin production can serve to protect this plant against its pathogens. Quite a few chemical compounds, derivatives of phytohormones bio-elicitors as well as biocontrol agents, have been used to induce the synthesis of stilbene phytoalexins with the aim of conferring protection to grapevine against its main diseases (gray mold, downy mildew, powdery mildew and esca). This article reviews the experiments that have been carried out in this direction during the last 30 years and shows that the observed protective effects towards pathogens are generally linked to induction and priming of the grapevine phytoalexin response, confirming the interest in using, in a more general way, stimulation of the production of phytoalexins in plants as a basis for crop protection.

Novel Finding on How Melatonin and Nanoselenium Alleviate 2,4-D Butylate Stress in Wheat Plants.

Nanoselenium (nano-Se) or melatonin (MT) foliar spray reduces pesticide stress by stimulating plant secondary metabolism and antioxidant capacity. However, the effects of nano-Se and MT biofortification on the interaction between plant secondary metabolic pathways and rhizosphere microbes in mitigating 2,4-D butyrate stress remain unknown. Compared to nano-Se or MT treatment alone, nano-Se and MT combined application increased the antioxidant enzyme activities and decreased the MDA (25.0%) and H2O2 (39.3%) contents with 2,4-D butylate exposure. Importantly, they enhance the soil enzymes (S-FDA by 53.1%), allelochemicals (luteolin by 164.1% and tricin by 147.3%), as well as plant secondary metabolites (JA by 63.3% and 193.3% in leaves and roots) levels. It also improved the beneficial microbial abundance of Comamonadaceae, Sphingomonadaceae, and Rhodobacteraceae in the rhizosphere soil. In conclusion, nano-Se and MT alleviate 2,4-D butylate stress in wheat plants by enabling the interaction between rhizosphere microorganisms, allelopathic substances, and secondary metabolites.

Effect of Ozone Stresses on Growth and Secondary Plant Metabolism of Brassica campestris L. ssp. chinensis

Determining plant responses to hazardous air pollutants is critical in predicting food security programs and challenges in the future. This study aimed to determine the effects of various ozone levels on plant growth responses (leaf area, dry matter, and number of leaves) and biochemical quality (photopigments and glucosinolates) on Brassica campestris L. ssp. chinensis (Pak-Choi). The experiment was conducted within test chambers under different ozone concentrations (60, 150, and 240 ppb for 2 h/day). Leaf area and dry matter were negatively correlated with increasing ozone concentrations, but the number of leaves was not affected by ozone treatment. Lycopene and chlorophylls also showed the same tendency. Even if the ambient ozone concentration was only elevated for a short time, various glucosnilates (GLS) have been diversely affected. The total aliphatic GLS content was reduced. In contrast, the total indole GLS increased at the highest ozone concentration, and the aromatic GLS significantly increased and then decreased as the ozone concentration level increased. These results provide evidence of the strong effect of ozone stress on the plant quality of Pak-Choi with respect to certain secondary plant metabolites. These findings provide an understanding of elevated ozone effects in urban horticulture sites on the growth and metabolite profiling of Brassica plants.

Uses of Multi-Objective Flux Analysis for Optimization of Microbial Production of Secondary Metabolites.

Secondary metabolites are not essential for the growth of microorganisms, but they play a critical role in how microbes interact with their surroundings. In addition to this important ecological role, secondary metabolites also have a variety of agricultural, medicinal, and industrial uses, and thus the examination of secondary metabolism of plants and microbes is a growing scientific field. While the chemical production of certain secondary metabolites is possible, industrial-scale microbial production is a green and economically attractive alternative. This is even more true, given the advances in bioengineering that allow us to alter the workings of microbes in order to increase their production of compounds of interest. This type of engineering requires detailed knowledge of the "chassis" organism's metabolism. Since the resources and the catalytic capacity of enzymes in microbes is finite, it is important to examine the tradeoffs between various bioprocesses in an engineered system and alter its working in a manner that minimally perturbs the robustness of the system while allowing for the maximum production of a product of interest. The in silico multi-objective analysis of metabolism using genome-scale models is an ideal method for such examinations.

Artificial Light Spectra and Its Impact on Plant Physiological Processes and Secondary Metabolism

Understanding the effects of artificial light spectra on plant physiological processes and secondary metabolism is critical for optimizing plant growth and productivity, particularly in controlled environment agriculture. This review synthesizes the current knowledge on this topic, exploring the fundamental principles of light spectra, their impacts on plant physiology, including photosynthesis and growth, as well as on secondary metabolism. Artificial light sources, such as light-emitting diodes (LEDs), have been shown to significantly influence these plant processes, owing to their controllable spectra and intensities. These artificial light spectra can enhance photosynthetic efficiency, manipulate growth and development, and stimulate the production of valuable secondary metabolites. The review further discusses the potential applications of this understanding in sectors like agriculture, pharmaceuticals, nutraceuticals, and even space agriculture. However, the interactions of artificial light spectra with other environmental factors, the development of custom light recipes for specific plant species or cultivars, and the need for long-term studies are identified as areas needing further research. This review contributes to the growing body of literature exploring the opportunities and challenges of utilizing artificial light spectra for improving plant performance and secondary metabolite production.

Simulated organic–inorganic nitrogen deposition changes the growth rate, leaf stoichiometry, and phenolic content of Cyclocarya paliurus

Atmospheric nitrogen (N) deposition is composed of both organic nitrogen (ON) and inorganic nitrogen (IN), and these sources of N affect plant growth, the balance of elements, and the accumulation of secondary metabolism substances; however, how these plant traits respond to ON–IN N deposition remains unclear. Here, we explored the effects of N addition with different ON:IN ratios on the growth rate, biomass allocation, leaf N and phosphorus (P) concentration, and leaf phenolic content of Cyclocarya paliurus in a short-term field experiment. Compared with the control, the growth rate (μ) and biomass accumulation of C. paliurus showed a decreasing trend in the 2 years after different N addition treatments. Higher ON:IN ratios not only resulted in higher leaf N content but also significantly increased the leaf P content. In addition, N addition with different ON:IN ratios induced more biomass accumulation allocated to the underground part of C. paliurus, which may be related to the nutrient acquisition strategy. Increased leaf N:P ratios indicated that stoichiometric imbalance occurred and that N and P limitation conditions of C. paliurus changed after different ON–IN N treatments. The growth rate (μ) of C. paliurus showed a trend of first decreasing (14 < leaf N:P ratios < 16) and then increasing (16 < leaf N:P ratios). However, compared with the growth rate, the leaf phenolic content showed an opposite trend to that of leaf stoichiometry, which indicated that leaf stoichiometry significantly affected both the primary growth and secondary metabolism of plants. Our results suggest that simulated N addition with different ON:IN ratios caused stoichiometric imbalance and changed the plant growth rate and accumulation of biomass and secondary metabolism substances. In addition, our study highlights that the type of nutrient limitation and the variation in N deposition components should be considered when predicting the future responses of plant functional traits to N deposition.

Interaction of plant polysaccharides (inulin, guar gum) with the 20-hydroxyecdysone from quinoa and spinach

The use of plant extracts rich in primary and secondary plant metabolites as biostimulants in agriculture is a modern approach for increasing the sustainability of crops. Quinoa seeds (Chenopodium quinoa Willd.) and spinach leaves (Spinacia oleracea L.) are a valuable source of biologically active compounds of plant secondary metabolism such as polyphenolic compounds and ecdysteroids. An important producers of primary plant metabolites – polysaccharides – are common chicory (Cichorium intybus L.), used to obtain inulin and cluster bean (Cyamopsis tetragonoloba (L.) Taub.), which accumulates guar gum. The study of the interaction of primary and secondary metabolites of plants is an essential component of research in order to increase their resistance to biodegradation and preserve the optimum of biological action. This paper presents data from a preliminary study of the interactions of components derived from plant raw materials in an in vitro model system. Evaluation of the sorption capacity of plant polysaccharides (inulin, guar gum) was carried out in relation to 20-hydroxyecdysone (20E) – a minor biologically active substance (BAS) of extracts from spinach leaves and quinoa seeds. The sorption ratio of 20E was 92.25-95.87% for the studied concentrations of inulin model solutions. Sorption ratio for a solution of guar gum with a concentration of 0.5% was 94.17-96.00%, in other cases, a complete sorption of 20E was observed. Thus, one should be guided by the optimal ratio of polysaccharides and extracts enriched with 20E to ensure the maximum physiological effect.

Evolutionary signatures of a trade-off in direct and indirect defenses across the wild grape genus Vitis.

Evolutionary correlations between chemical defense and protection by mutualist bodyguards have been long predicted, but tests of these pattern remain rare. We use a phylogenetic framework to test for evolutionary correlations indicative of trade-offs or synergisms between direct defense in the form of plant secondary metabolism, and indirect defense in the form of leaf domatia, across 33 species in the wild grape genus, Vitis. We also performed a bioassay with a generalist herbivore to associate our chemical phenotypes with herbivore palatability. Finally, we tested whether defensive traits correlate with the average abiotic characteristics of each species' contemporary range and whether these correlations were consistent with plant defense theory. We found a negative evolutionary correlation between domatia size and the diversity of secondary metabolites in Vitis leaf tissue across the genus, and also that leaves with a higher diversity and richness of secondary metabolites were less palatable to a generalist herbivore, consistent with a trade-off in chemical and mutualistic defense investment. Predictions from plant defense theory were not supported by associations between investment in defense phenotypes and abiotic variables. Our work demonstrates an evolutionary pattern indicative of a trade-off between indirect and direct defense strategies across the Vitis genus.

Salicylic acid regulates phenolic acid biosynthesis via SmNPR1-SmTGA2/SmNPR4 modules in Salvia miltiorrhiza.

Phenolic acids are the main active ingredients in Salvia miltiorrhiza, which can be used for the treatment of many diseases, particularly cardiovascular diseases. It is known that salicylic acid (SA) can enhance phenolic acid content, but the molecular mechanism of its regulation is still unclear. The nonexpresser of PR genes 1 (NPR1) plays a positive role in the SA signaling pathway. In this study, we identified a SmNPR1 gene that responds to SA induction and systematically investigated its function. We found that SmNPR1 positively affected phenolic acid biosynthesis. Then, we identified a novel TGA transcription factor, SmTGA2, which interacts with SmNPR1. SmTGA2 positively regulates phenolic acid biosynthesis by directly up-regulating SmCYP98A14 expression. After double-gene transgenic analysis and other biochemical assays, it was found that SmNPR1 and SmTGA2 work synergistically to regulate phenolic acid biosynthesis. In addition, SmNPR4 forms a heterodimer with SmNPR1 to inhibit the function of SmNPR1, and SA can alleviate this effect. Collectively, these findings elucidate the molecular mechanism underlying the regulation of phenolic acid biosynthesis by SmNPR1-SmTGA2/SmNPR4 modules and provide novel insights into the study of the SA signaling pathway regulating plant secondary metabolism.

Synthesis, spectroscopic characterization, and antibacterial activity of chalcone (2E)-1-(3'-aminophenyl)-3-(4-dimethylaminophenyl)-prop-2-en-1-one against multiresistant Staphylococcus aureus carrier of efflux pump mechanisms and β-lactamase.

The bacterium Staphylococcus aureus has stood out for presenting a high adaptability, acquiring resistance to multiple drugs. The search for natural or synthetic compounds with antibacterial properties capable of reversing the resistance of S. aureus is the main challenge to be overcome today. Natural products such as chalcones are substances present in the secondary metabolism of plants, presenting important biological activities such as antitumor, antidiabetic, and antimicrobial activity. In this context, the aim of this work was to synthesize the chalcone (2E)-1-(3'-aminophenyl)-3-(4-dimethylaminophenyl)-prop-2-en-1-one with nomenclature CMADMA, confirm its structure by nuclear magnetic resonance (NMR), and evaluate its antibacterial properties. The synthesis methodology used was that of Claisen-Schmidt, and spectroscopic characterization was performed by NMR. For microbiological assays, the broth microdilution methodology was adopted in order to analyze the antibacterial potential of chalcones and to analyze their ability to act as a possible inhibitor of β-lactamase and efflux pump resistance mechanisms, present in S. aureus strain K4100. The results obtained show that CMADMA does not show direct antibacterial activity, expressing a MIC of ≥1024 μg/mL, or on the enzymatic mechanism of β-lactamase; however, when associated with ethidium bromide in efflux pump inhibition assays, CMADMA showed promising activity by reducing the MIC of the bromide from 64 to 32 μg/mL. We conclude that the chalcone synthesized in this study is a promising substance to combat bacterial resistance, possibly acting in the inhibition of the QacC efflux pump present in S. aureus strain K4100, as evidenced by the reduction in the MIC of ethidium bromide.

Analysis of the effects of sulfamethoxazole on the secondary metabolites and antioxidants in oilseed rape (Brassica napus L.) and the underlying mechanisms

The secondary metabolism of plants is key for mediating responses to environmental stress, but few studies have examined how the relationship between secondary metabolism and the stress response of plants is affected by exposure to antibiotics. Here, we studied the effects of sulfamethoxazole (SMZ) on the secondary metabolism and antioxidant activity of oilseed rape (Brassica napus L.). SMZ significantly affected the growth of rape seedlings. Low and high concentrations of SMZ induced the production of a large number of reactive oxygen species (ROS) in rape seedlings, which damaged cells. SMZ stress altered the activity of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), as well as the content of malondialdehyde (MDA). SMZ promoted the activities of phenylalanine ammonia lyase (PAL), tyrosine ammonia lyase (TAL), cinnamic acid-4-hydroxylase (C4H), and 4-coumaric acid: coenzyme A ligase (4CL) by activating the phenylpropanoid pathway. The content of secondary metabolites changed. The content of phenolic acids and flavonoids increased, and the content of sinapine and anthocyanins was altered to cope with the oxidative damage induced by antibiotics. Transcriptomic and metabolomic analysis showed that differentially expressed genes and differentially expressed metabolites were mainly involved in Phenylpropanoid biosynthesis. SMZ alters the secondary metabolites of rapeseed, which mitigates the deleterious effects of stress, by modulating upstream secondary metabolism pathways and the production of plant hormones involved in signal transduction. In sum, these results provide a new perspective on the effects of SMZ on plants relative to secondary metabolites and improve our understanding of the toxicity of SMZ.

Biochar and Seed Priming Technique with Gallic Acid: An Approach toward Improving Morpho-Anatomical and Physiological Features of Solanum melongena L. under Induced NaCl and Boron Stresses.

Dynamic shifts in climatic patterns increase soil salinity and boron levels, which are the major abiotic factors that affect plant growth and secondary metabolism. The present study assessed the role of growth regulators, including biochar (5 g kg-1) and gallic acid (GA, 2 mM), in altering leaf morpho-anatomical and physiological responses of Solanum melongena L. exposed to boron (25 mg kg-1) and salinity stresses (150 mM NaCl). These growth regulators enhanced leaf fresh weight (LFW) (70%), leaf dry weight (LDW) (20%), leaf area (LA), leaf area index (LAI) (85%), leaf moisture content (LMC) (98%), and relative water content (RWC) (115%) under salinity and boron stresses. Physiological attributes were analyzed to determine the stress levels and antioxidant protection. Photosynthetic pigments were negatively affected by salinity and boron stresses along with a nonsignificant reduction in trehalose, GA, osmoprotectant, and catalase (CAT) and ascorbate peroxidase (APX) activity. These parameters were improved by biochar application to soil and presoaking seeds in GA (p < 0.05) in both varieties of S. melongena L. Scanning electron microscopy (SEM) and light microscopy revealed that application of biochar and GA improved the stomatal regulation, trichome density, epidermal vigor, stomata size (SS) (13 381 μm), stomata index (SI) (354 mm2), upper epidermis thickness (UET) (123 μm), lower epidermis thickness (LET) (153 μm), cuticle thickness (CT) (11.4 μm), trichome density (TD) (23 per mm2), vein islet number (VIN) (14 per mm2), vein termination number (VTN) (19 per mm2), midrib thickness (MT) (5546 μm), and TD (27.4 mm2) under salinity and boron stresses. These results indicate that the use of inexpensive and easily available biochar and seed priming with GA can improve morpho-anatomical and physiological responses of S. melongena L. under oxidative stress conditions.

Global proteome and lysine succinylation analyses provide insights into the secondary metabolism in Salvia miltiorrhiza

Danshen, belongs to the Lamiaceae family, and its scientific name is Salvia miltiorrhiza Bunge. It is a valuable medicinal plant to prevent and treat cardiovascular and cerebrovascular diseases. Lysine succinylation, a widespread modification found in various organisms, plays a critical role in regulating secondary metabolism in plants. The hairy roots of Salvia miltiorrhiza were subject to proteomic analysis to identify lysine succinylation sites using affinity purification and HPLC-MS/MS in this investigation. Our findings reveal 566 lysine succinylation sites in 348 protein sequences. We observed 110 succinylated proteins related to secondary metabolism, totaling 210 modification sites. Our analysis identified 53 types of enzymes among the succinylated proteins, including phenylalanine ammonia-lyase (PAL) and aldehyde dehydrogenase (ALDH). PAL, a crucial enzyme involved in the biosynthesis of rosmarinic acid and flavonoids, displayed succinylation at two sites. ALDH, which participates in the phenylpropane metabolic pathway, was succinylated at 8 eight sites. These observations suggest that lysine succinylation may play a vital role in regulating the production of secondary metabolites in Salvia miltiorrhiza. Our study may provide valuable insights for further investigation on plant succinylation, specifically as a reference point. SignificanceSalvia miltiorrhiza Bunge is a valuable medicinal plant that prevents and treats cardiovascular and cerebrovascular diseases. Lysine succinylation plays a critical role in regulating secondary metabolism in plants. The hairy roots of Salvia miltiorrhiza were subject to proteomic analysis to identify lysine succinylation sites using affinity purification and HPLC-MS/MS in this investigation. These observations suggest that lysine succinylation may act as a vital role in regulating the production of secondary metabolites in Salvia miltiorrhiza. Our study may provide valuable insights for further investigation on succinylation in plants, specifically as a reference point.

Phytochemical and Biological Properties of Domesticated Capsicum Species: A Review

America is the original home of the Capsicum genus (Solanaceae). It is now a significant agricultural crop grown all over the world, not only for its commercial significance but also for the fruits' high nutritional worth. Capsicum and its various variants have many beneficial qualities that set them apart from other vegetables. They are also used as a spice in many foods due to its potent, pungent flavour, which is created during the plant's secondary metabolism. Due to the presence of carotenoids, which can be utilised as a natural colouring agent and antioxidant, capsicum fruit displays a diverse colour profile. Capsaicinoids, one of their phytochemical components, give sharp-tasting cultivars their typical pungency. Capsicum and its capsaicinoids, particularly capsaicin, have also received a lot of research attention due to their health advantages. Additionally, the essential oils from capsicum are used in cosmetics as anti-aging ingredients. Thus, this study covers the scientific literature on Capsicum species and their phytochemicals, which have been shown to have protective effects against cancer, diabetes, gastrointestinal disorders, pain, and metabolic syndrome as well as having antibacterial and antioxidant properties. The chemical and functional characteristics of the bioactive chemicals derived from capsicum and their successful application in the pharmaceutical, food, agricultural, cosmetic, and textile sectors.

Ginkgo biloba GbbZIP08 transcription factor is involved in the regulation of flavonoid biosynthesis

Ginkgo biloba is the oldest relict plant on Earth and an economic plant resource derived from China. Flavonoids extracted from G. biloba are beneficial to the prevention and treatment of cardiovascular and cerebrovascular diseases. Basic leucine zipper (bZIP) transcription factors (TFs) have been recognized to play important roles in plant secondary metabolism. In this study, GbbZIP08 was isolated and characterized. It encodes a protein containing 154 amino acids, which belongs to hypocotyl 5 in group H of the bZIP family. Tobacco transient expression assay indicated that GbbZIP08 was localized in the plant nucleus. GbbZIP08 overexpression showed that the contents of total flavonoids, kaempferol, and anthocyanin in transgenic tobacco were significantly higher than those in the wild type. Transcriptome sequencing analysis revealed significant upregulation of structural genes in the flavonoid biosynthesis pathway. In addition, phytohormone signal transduction pathways, such as the abscisic acid, salicylic acid, auxin, and jasmonic acid pathways, were enriched with a large number of differentially expressed genes. TFs such as MYB, AP2, WRKY, NAC, bZIP, and bHLH, were also differentially expressed. The above results indicated that GbbZIP08 overexpression promoted flavonoid accumulation and increased the transcription levels of flavonoid-synthesis-related genes in plants.

Imidacloprid-induced stress affects the growth of pepper plants by disrupting rhizosphere-plant microbial and metabolite composition

Overusing imidacloprid (IMI) has been found to impede secondary metabolism and hinder plant growth. The impact of IMI stress on the interaction between metabolites, rhizosphere, and plant-microbe dispersion through various pathways in pepper plants has not been extensively studied. This study investigated the effects of IMI on plant signaling components, secondary metabolic pathways, and microbial communities in the rhizosphere and phyllosphere. Here, the distribution of IMI and its metabolites (6-chloronicotinic acid, IMI-desnitro, 5-hydroxy-IMI, IMI-urea, and IMI-olefin) was primarily observed in the pepper plant leaves. A rise in IMI concentration had a more significant inhibitive effect on the metabolism of pepper leaves than on pepper roots. The findings of non-target metabolomics indicated that IMI exposure primarily suppresses secondary metabolism in pepper plants, encompassing flavones, phenolic acids, and phytohormones. Notably, the IMI treatment disrupted the equilibrium between plants and microbes by decreasing the population of microorganisms such as Vicinamibacteria, Verrucomicrobiae, Gemmatimonadetes, and Gammaproteobacteria in the phyllosphere, as well as Vicinamibacteria, Gemmatimonadetes, Gammaproteobacteria, and Alphaproteobacteria in the rhizosphere of pepper plants. The study demonstrates that overexposure to IMI harms microbial composition and metabolite distribution in the rhizosphere soil and pepper seedlings, inhibiting plant growth.

Identification and Infrared Spectroscopic Study of Lapachol, β-Lapachone and Hydroxy-hydrolapachol

Metabolites of Brazilian Cerrado species are considered an immense font of biologically active compounds The diversity of organic compounds generated by the secondary metabolism of various Cerrado plants draws attention especially because many of these compounds have the capacity to be structurally modified and, consequently, produce other very interesting derivatives for pharmacological purposes. Despite this, little is described in the literature about fast, easy, and accessible identification methods for any laboratory, such as infrared spectroscopy. In this sense, this work demonstrates the synthesis and elucidation through spectroscopic techniques of lapachol and its synthetic derivatives. Through quick and simple extractions or reactions, lapachol, β-lapachone, and hydroxy-hydrolapachol were obtained with adequate yields. From this, the main FTIR absorptions of the mentioned naphthoquinones are described, which facilitates the identification of these metabolites with high biological potential. The present work contributes could become a simpler source of data for extraction, synthesis, and spectroscopic characterization by FTIR of the compounds.

Genome-wide identification of SrbHLH transcription factors highlights its potential role in rebaudioside A (RA) biosynthesis in Stevia rebaudiana

Stevia rebaudiana Bertoni is a valuable medicinal plant and an essential source of natural sweetener, steviol glycosides (SGs), with rebaudioside A (RA) being one of the main components of SGs. bHLH transcription factors play a crucial role in plant development and secondary metabolism. In this study, 159 SrbHLH genes were identified from the S. rebaudiana genome, and each gene was named based on its chromosome location. The SrbHLH proteins were then clustered into 18 subfamilies through phylogenetic analysis. The analysis of conserved motifs and gene structure further supported the classification of the SrbHLH family. Chromosomal location and gene duplication events of SrbHLH genes were also studied. Moreover, based on the RNA-Seq data of different tissues of S. rebaudiana, 28 SrbHLHs were co-expressed with structural genes involved in RA biosynthesis. The expression pattern of candidate SrbHLH genes were confirmed by qPCR. Finally, dual luciferase reporter assays (DLAs) and subcellular localization analysis verified SrbHLH22, SrbHLH111, SrbHLH126, SrbHLH142, and SrbHLH152 are critical regulators of RA biosynthesis. This study provides new insights into the function of SrbHLHs in regulating SGs biosynthesis and lays the foundation for future applications of SrbHLH genes in molecular breeding of S. rebaudiana.

Combined Small RNA and Degradome Sequencing Reveals Important Roles of Light-Responsive microRNAs in Wild Potato (Solanum chacoense)

The accumulation of chlorophyll and antinutritional glycoalkaloids in potato tubers resulting from exposure to light has been widely recognized as a cause of unpredictable quality loss of potato tuber. While transcriptional regulation of light-induced chlorophyll and glycoalkaloids accumulation has been extensively investigated, the mechanisms of post-transcriptional regulation through miRNA remain largely unexplored. An experimental model, the tubers of Solanum chacoense, were used to identify light-responsive miRNA–target interactions (MTIs) related to tuber greening and glycoalkaloid biosynthesis by employing multi-omics approaches (miRNA-seq and degradome-seq). A total of 732 unique mature miRNAs have been identified in S. chacoense. In total, 6335 unique target transcripts were cleaved by 489 known miRNAs and 153 novel miRNAs. The results revealed that light-responsive miRNAs can be grouped into eight temporally related clusters and play important roles in various physiological processes such as plant growth, stress responses, and primary and secondary metabolism. Multi-omics analyses have revealed that the modulation of transcript abundance of MYB59, HSPs, and EBF1/EBF2 by light-responsive miRNAs is pivotal for their function in cross-tolerance responses to both abiotic and biotic stresses. Furthermore, our findings suggest that many light-responsive miRNAs are crucial regulators in various biosynthetic pathways, including tetrapyrrole biosynthesis, suberin biosynthesis, and steroid biosynthesis. These findings highlight the significant role of light-responsive miRNAs in secondary metabolic pathways, particularly in isoprenoid, terpenoid, and glycoalkaloid biosynthesis, and have implications for the precise manipulation of metabolic pathways to produce new potato varieties with improved resistance to greening and lower glycoalkaloid levels.