Chalcone Isomerase Research Articles

Transcriptional regulatory mechanisms of flavonoid metabolism from flower bud to flower in Hemerocallis citrina

The flower buds of Hemerocallis citrina are well-known functional foods in East Asian countries for their promoting intelligence and forgetting worries, in which their nutrients, especially flavonoids, play an important role. However, they will be discarded when the buds develop into flowers, part of the reason is the type and content of flavonoids change considerably. At present, the developmental mechanism responsible for these differences is still unclear. Based on "multi-omics" technologies, the results of this study revealed that 18 flavonoids were significantly differential, including five flavonoids, eight flavonols and three flavanones, one isoflavone and one anthocyanin, and their biosynthesis involved 50 differential genes and 25 differential enzyme proteins. Among them, nine genes encoding four key enzymes (chalcone isomerase, isoflavone 2′-hydroxylase, flavonol-3-O-l-rhamnoside-7-O-glucosyltransferase and phlorizin synthase) were targeted by seven conserved miRNA (microRNA) families, covering miR394, miR477, miR396, miR528, miR164, miR395 and miR447. Furthermore, 10 genes encoding five transcription factor families (bZIP (basic leucine zipper), NAC (NAM, ATAF1/2 and CUC2), GRAS (GAI, RGA and SCR), TCP (TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTOR) and MADS (MCM1/AGAMOUS/DEFICIENS/SRF)) were targeted by seven conserved miRNA families, including miR393, miR166, miR171, miR477, miR164, miR528 and miR447. They are jointly involved in the metabolic regulation of flavone and flavonol biosynthesis, isoflavonoid biosynthesis, and flavonoid biosynthesis from flower buds to flowering development of H. citrina.

An Overview of Biosynthetic Pathway and Therapeutic Potential of Naringin

Abstract: Naringin is a naturally obtained chemical from plants that is formed as a secondary metabolite in them. It possesses significant properties that are useful to humans. The primary sources of naringin extract include fruits of the citrus family which are Citrus reticulata, Citrus bergamia, Citrus aurantium, and Citrus paradisi. It belongs to a class of alcohols primarily consisting of a fused ring system which is responsible for its different medicinal properties, as a consequence, it is widely used in the nutraceutical market nowadays. Nutraceuticals are a part of food that provides health benefits by giving supplements to the body; their final extract form is white in color having crystalline properties with a melting point of 83oC and solubility of 1 mg/ml at 40oC. The absorption of nutraceuticals occurs inside the stomach as it requires a specific pH range between 3.5-4.2. After absorption, it gets converted into naringenin in the liver via a cascade of reactions like dehydrogenation, acetylation, and hydrolysis. Several enzymes are responsible for its conversion into an active form which includes cytochrome P-450, and chalcone isomerase. Its bioavailability depends on a variety of factors including disease condition, gastric moiety, pH of absorption site, the presence of other drugs, and many more. It gets metabolized in the liver itself and finally excreted in the urine. It can be tolerated by the body at high doses, but other conditions can cause its toxicity inside the human body. Its primary properties include anti-inflammatory actions, anti-aging properties, antibacterial properties, anti-cancer properties, and obesity issues.

UV-C radiation promoted flavonoid synthesis during early healing in potato tuber wounds with the possible involvement of ABA and related transcription factor regulation

UV-C radiation has been widely proven to promote flavonoid synthesis in fruit and vegetables as an environmentally friendly treatment. However, it is unknown whether UV-C promotes flavonoid synthesis in potato tuber wounds during early healing and its possible regulatory mechanism. In this study, UV-C radiation increased the gene expression and activities of zeaxanthin epoxidase (ZEP) and 9-cis-epoxycarotenoid dioxygenase (NCED), and increased ABA levels. Meanwhile, UV-C upregulated the expression levels of StPYR1, StPYR2, StPYR3, StPP2C, SnRK2.1 and StABF, and promoted ABA signaling in tuber wounds. In addition, UV-C upregulated the expression levels of related transcription factors, including StMYB12, StMYB308, StbHLH93 and StbHLH143. Furthermore, UV-C regulated the gene expression and activities of chalcone synthase (CHS), chalcone isomerase (CHI), flavanone 3-hydroxylase (F3H) and flavonol synthase (FLS), and promoted the accumulation and synthesis of flavonoids in tuber wounds. It is suggested that ABA and related transcription factors, including StMYB12, StMYB308, StbHLH93 and StbHLH143, may be involved in the regulation of UV-C radiation-driven flavonoid synthesis in potato tuber wounds during early healing.

Metabolic Profiling and Molecular Mechanisms Underlying Melatonin-Induced Secondary Metabolism of Postharvest Goji Berry (Lycium barbarum L.).

Postharvest decay of goji berries, mainly caused by Alternaria alternata, results in significant economic losses. To investigate the effects of melatonin (MLT) on resistance to Alternaria rot in goji berries, the fruits were immersed in the MLT solutions with varying concentrations (0, 25, 50, and 75 μmol L-1) and then inoculated with A. alternata. The results showed that the fruits treated with 50 μmol L-1 MLT exhibited the lowest disease incidence and least lesion diameter. Meanwhile, endogenous MLT in the fruits treated with 50 μmol L-1 MLT showed higher levels than in the control fruits during storage at 4 ± 0.5 °C. Further, the enzymatic activities and expressions of genes encoding peroxidase, phenylalanine ammonia-lyase, cinnamate 4-hydroxylase, 4-coumarate-CoA ligase, chalcone synthase, chalcone isomerase, and cinnamyl alcohol dehydrogenase were induced in the treated fruit during storage. UPLC-ESI-MS/MS revealed that secondary metabolites in the fruits on day 0, in order of highest to lowest levels, were rutin, p-coumaric acid, chlorogenic acid, ferulic acid, caffeic acid, naringenin, quercetin, kaempferol, and protocatechuic acid. MLT-treated fruits exhibited higher levels of secondary metabolites than the control. In conclusion, MLT treatment contributed to controlling the postharvest decay of goji fruit during storage by boosting endogenous MLT levels, thus activating the antioxidant system and secondary metabolism.

Integrative metabolome and transcriptome analyses reveal the mechanism by which white light increases apple phenolics

Apple is a photophilic fruit and the nutrients content such as phenolics loss is a major problem during fruit storage. Light can affect the yield, appearance and quality of apples. However, the molecular mechanism behind how white light induces phenolics accumulation to improve quality in fruits remains unclear. In this study, we discovered that white light with an intensity of 4 w/m2 can enhance the total phenolic and flavonoid content in postharvest apple fruits. To investigate the specific phenolics that undergo changes during this process, we analyzed the metabolomes of apples exposed to white light for 5 days after harvesting. We identified a total of 97 differentially accumulated metabolites (DAMs), including 15 phenolics. Isorhamnetin-O-hexos, tangereti, phloretin, cis-p-coumaroyltartaric acid and cis-p-coumaroyltartaric acid contents decreased in white light. While myricetin 3-O-galactoside, astilbin, sieboldin 2′-hydroxygenistein, syringaresinol, pinoresino, maleoyl-caffeoylquinic acid, rosmarinyl glucosid, coniferyl alcohol, p-coumaryl alcoho, and feruloylferuloyltartaric acid contents increased in white light. Additionally, RNA-seq analysis allowed us to identify 1988 differentially expressed genes (DEGs), which included three key enzymes (phenylalanine ammonia-lyase [MdPAL-1], chalcone isomerase [MdCHI-like], and 4-coumarate: -CoA ligase [Md4CL-1]) involved in the phenolic synthesis pathway, as well as a basic leucine zipper domain (bZIP) transcription factor known as MdbZIP67. Further investigations revealed that white light can regulate the transcription of MdPAL-1, Md4CL-1, and MdCHI-like genes through MdbZIP67, resulting in an increase in phenolic content during fruit storage. Here, we have identified a new method to enhance the phenolic content in apple fruits with characteristics of easy to use and low cost. And we have elucidated the mechanism by which white light affects phenolic content during the fruit's shelf life.

The challenge of breeding for reduced off-flavor in faba bean ingredients.

The growing interest in plant protein sources, such as pulses, is driven by the necessity for sustainable food production and climate change mitigation strategies. Faba bean (Vicia faba L.) is a promising protein crop for temperate climates, owing to its remarkable yield potential (up to 8 tonnes ha-1 in favourable growing conditions) and high protein content (~29% dry matter basis). Nevertheless, the adoption of faba bean protein in plant-based products that aim to resemble animal-derived counterparts is hindered by its distinctive taste and aroma, regarded as "off-flavors". In this review, we propose to introduce off-flavor as a trait in breeding programs by identifying molecules involved in sensory perception and defining key breeding targets. We discuss the role of lipid oxidation in producing volatile and non-volatile compounds responsible for the beany aroma and bitter taste, respectively. We further investigate the contribution of saponin, tannin, and other polyphenols to bitterness and astringency. To develop faba bean varieties with diminished off-flavors, we suggest targeting genes to reduce lipid oxidation, such as lipoxygenases (lox) and fatty acid desaturases (fad), and genes involved in phenylpropanoid and saponin biosynthesis, such as zero-tannin (zt), chalcone isomerase (chi), chalcone synthase (chs), β-amyrin (bas1). Additionally, we address potential challenges, including the need for high-throughput phenotyping and possible limitations that could arise during the genetic improvement process. The breeding approach can facilitate the use of faba bean protein in plant-based food such as meat and dairy analogues more extensively, fostering a transition toward more sustainable and climate-resilient diets.

Multi-omics analysis reveals the molecular basis of flavonoid accumulation in fructus of Gardenia (Gardenia jasminoides Ellis)

BackgroundThe fruits of Gardenia are rich in flavonoids and geniposides, which have various pharmacological effects such as antioxidant, anti-inflammatory and anticancer. In this study, we analyzed the transcriptome and metabolome of gardenia peel and kernel at different growth stages, revealed the regulatory network related to flavonoid synthesis, and identified the key regulatory genes.ResultsThe results showed that in terms of flavonoid metabolic pathways, gardenia fruits mainly synthesized cinnamic acid through the phenylpropanoid pathway, and then synthesized flavonoids through the action of catalytic enzymes such as 4-coumaroyl-CoA ligase, chalcone synthase, chalcone isomerase and flavanol synthase, respectively. In addition, we found that the metabolomics data showed a certain spatial and temporal pattern in the expression of genes related to the flavonoid metabolism pathway and the relative content of metabolites, which was related to the development and ripening process of the fruit.ConclusionsIn summary, this study successfully screened out the key genes related to the biosynthesis metabolism of flavonoids in gardenia through the joint analysis of transcriptome and metabolome. This is of certain significance to the in-depth study of the formation mechanism of gardenia efficacy components and the improvement of quality.

Genetic Channelization Mechanism of Four Chalcone Isomerase Homologous Genes for Synergistic Resistance to Fusarium wilt in Gossypium barbadense L.

Duplication events occur very frequently during plant evolution. The genes in the duplicated pathway or network can evolve new functions through neofunctionalization and subfunctionalization. Flavonoids are secondary metabolites involved in plant development and defense. Our previous transcriptomic analysis of F6 recombinant inbred lines (RILs) and the parent lines after Fusarium oxysporum f. sp. vasinfectum (Fov) infection showed that CHI genes have important functions in cotton. However, there are few reports on the possible neofunctionalization differences of CHI family paralogous genes involved in Fusarium wilt resistance in cotton. In this study, the resistance to Fusarium wilt, expression of metabolic pathway-related genes, metabolite content, endogenous hormone content, reactive oxygen species (ROS) content and subcellular localization of four paralogous CHI family genes in cotton were investigated. The results show that the four paralogous CHI family genes may play a synergistic role in Fusarium wilt resistance. These results revealed a genetic channelization mechanism that can regulate the metabolic flux homeostasis of flavonoids under the mediation of endogenous salicylic acid (SA) and methyl jasmonate (MeJA) via the four paralogous CHI genes, thereby achieving disease resistance. Our study provides a theoretical basis for studying the evolutionary patterns of homologous plant genes and using homologous genes for molecular breeding.

Analysis of the transcriptome and metabolome reveals phenylpropanoid mechanism in common bean (Phaseolus vulgaris) responding to salt stress at sprout stage

AbstractCommon bean (Phaseolus vulgaris) seeds are important legume crops and an important source of dietary proteins and carbohydrates. Therefore, it is important to develop strategies to improve salt tolerance in common beans. In this study, transcriptome and metabolome analyses were conducted on local common bean variety under salt stress at the sprout stage for a period of 0, 12, and 24 h. Results showed that phenylpropanoid pathways (including phenylpropanoid biosynthesis and phenylalanine metabolism) and flavonoid pathways (including flavonoid biosynthesis and flavone and flavonol biosynthesis) played an important role in controlling responses to salt stress as evidenced by analysis of differentially expression genes, common expression patterns, WCGNA, and differentially altered metabolites (DAMs) analyses. In addition, exploration of the activities of 4‐coumarate‐CoA ligase (4CL), caffeoyl‐CoA O‐methyltransferase (CCoAOMT), peroxidase (POD), chalcone isomerase (CHI), dihydroflavonol‐4‐reductase (DFR), and flavonol synthase (FLS) further showed that phenylpropanoid and flavonoid pathways participate in plant responses to salt stress. Moreover, the phenylpropanoid pathways and flavonoid pathways were found to be potential pathways regulating plant response to salt stress based on transcriptome and metabolome analysis. The activities of 4CL, CCoAOMT, POD, CHI, DFR, and FLS revealed that these pathways are crucial to the regulation of plant responses to salt stress. These findings provided theoretical basis for further improvement of salt tolerance in common bean.

Integrated Transcriptomics and Metabolomics Analysis Reveal Anthocyanin Biosynthesis for Petal Color Formation in Catharanthus roseus

Catharanthus roseus exhibits vibrant petals and displays robust resistance to disease and drought, making it highly valuable for ornamental and gardening applications. While the application of C. roseus as a source of anticancer drugs has gained considerable attention in recent years, there has been limited investigation into the regulatory mechanism underlying anthocyanin accumulation in the petals of C. roseus. This study comprehensively analyzed the metabolome and transcriptome of three distinct C. roseus varieties exhibiting different petal colors. Out of the 39 identified flavonoids, 10 anthocyanins exhibited significant variations in accumulation, directly contributing to the diverse coloration of C. roseus petals. Among them, malvidin 3-O-glucoside and petunidin 3-O-glucoside were identified as primary contributors to the purple petal phenotype, while peonidin 3-O-glucoside and delphinidin 3-O-glucoside exhibited the highest contribution rates to the red petals. Additionally, the variation content of cyanidin 3-O-rutinoside, delphinidin 3-O-glucoside, and petunidin 3-O-rutinoside also influenced the color transformation of C. roseus petals. RNA sequencing identified a total of 4173 differentially expressed genes (DEGs), including 1003 overlapping DEGs. A combined transcriptome and metabolome analysis showed that the coordinately regulated anthocyanin biosynthetic genes including chalcone isomerase (CHS), flavonoid 3′-hydroxylase (F3′H), and dihydroflavonol 4-reductase (DFR) played critical roles in the formation of the anthocyanins. MYB and bHLH transcription factors were also found to be significantly correlated with differences in flower color. These results serve as a foundation for future investigations into anthocyanin biosynthesis and regulatory mechanisms in C. roseus.

Phenolic Compounds of the Medicinal Plants in an Anthropogenically Transformed Environment.

In this article, the impact of an anthropogenically transformed environment on the content of pharmaceutically valuable biologically active compounds in medicinal plants is analyzed. The studied biologically active substances included phenolic compounds (flavonoids, anthocyanins, tannins, and phenolic acids). The number of transmissible forms of heavy metals (HMs), including cadmium, lead, and mercury, were discharged from factories that are present in the soil. Plants uptake these toxic metals from the soil. HM causes changes in the activity of the several enzymes such as phenylalanine ammonia lyase (PAL), chalcone synthase (CHS), chalcone isomerase (CHI) and other enzymes. These enzymes play an important role in biosynthesis of phenolic compounds in medicinal plants. It has been demonstrated that plant materials possess high antioxidant potential due to their high phenolic content. As a result, the present review discusses a thorough investigation of anthropogenically transformed environment effects on the quantity of pharmaceutically valuable phenolic compounds in medicinal plants.

Effects of salicylic acid-grafted bamboo hemicellulose on gray mold control in blueberry fruit: The phenylpropanoid pathway and peel microbial community composition

Bamboo hemicellulose (HC) is a natural plant polysaccharide with good biocompatibility and biodegradability. But its poor antibacterial activity limits its application in fruits preservation. In this study, based on the good inducer of salicylic acid (SA) for plant diseases resistance, a novel antibacterial coating material was synthesized by grafting SA onto HC. The study aimed to investigate the synergistic effect of HC-g-SA on antibacterial ability, induces diseases resistance and microbial community composition of postharvest fruit. The graft copolymer treatment significantly reduced the incidence of gray mold caused by Botrytis cinerea in blueberries during storage (P < 0.05), and significantly stimulated the activity of key enzymes, including phenylalanine ammonia-lyase, chalcone isomerase, laccase, and polyphenol oxidase, leading to an increase in fungicidal compounds such as flavonoids, lignin, and total phenolics produced by the phenylpropanoid pathway in blueberries (P < 0.05). Moreover, the HC-g-SA coating altered bacterial and fungal community composition such that the abundance of postharvest fruit-peel pathogens was significantly reduced. After 8 days storage, the blueberry fruits treated by HC-g-SA had a weight loss rate of 12.42 ± 0.85 %. Therefore, the HC-g-SA graft copolymer had a positive impact on the control of gray mold in blueberry fruit during postharvest storage.

De novo transcriptome analysis of Dysoxylum binectariferum to unravel the biosynthesis of pharmaceutically relevant specialized metabolites.

The tropical tree, D. binectariferum, is a prominent source of chromone alkaloid rohitukine, which is used in the semi-syntheses of anticancer molecules such as flavopiridol and P-276-00. The biosynthetic pathway of rohitukine or its derivatives is currently unknown in plants. Here, we explored chromone alkaloid biosynthesis in D. binectariferum through targeted transcriptome sequencing. Illumina sequencing of leaves and roots of a year-old D. binectariferum seedling generated, 42.43 and 38.74 million paired-end short reads, respectively. Quality filtering and de novo assembly of the transcriptome generated 274,970 contigs and 126,788 unigenes with an N50 contig length of 1560 bp. The assembly generated 117,619 translated unigene protein sequences and 51,598 non-redundant sequences. Nearly 80% of these non-redundant sequences were annotated to publicly available protein and nucleotide databases, suggesting the completeness and effectiveness of the transcriptome assembly. Using the assembly, we identified a chalcone synthase (CHS) and three type III polyketide synthases (PKS-III; non-CHS type) that are likely to be involved in the biosynthesis of chromone ring/noreugenin moiety of rohitukine. We also identified key enzymes like lysine decarboxylase in the piperidine pathway that make the piperidine moiety of rohitukine. Besides these, the upstream enzymes in flavonoid biosynthesis like phenylalanine ammonia-lyase (PAL), trans-cinnamate 4-hydroxylase (C4H),4-coumarate-CoA ligase (4CL), and chalcone isomerase (CHI) have also been identified. Also, terpene synthases that are likely to be involved in the biosynthesis of various terpenoid scaffolds have been identified. Together, the D. binectariferum transcriptome resource forms a basis for further exploration of biosynthetic pathways of these valuable compounds through functional validation of the candidate genes and metabolic engineering in heterologous hosts. Additionally, the transcriptome dataset generated will serve as an important resource for research on functional genomics and enzyme discovery in D. binectariferum and comparative analysis with other Meliaceae family members.

Genomic-wide identification and expression analysis of R2R3-MYB transcription factors related to flavonol biosynthesis in Morinda officinalis

BackgroundThe R2R3-MYB transcription factors are a crucial and extensive gene family in plants, which participate in diverse processes, including development, metabolism, defense, differentiation, and stress response. In the Lingnan region of China, Morinda officinalis is extensively grown and is renowned for its use as both a medicinal herb and food source. However, there are relatively few reports on the R2R3-MYB transcription factor family in M.officinalis.ResultsIn this study, we identified 97 R2R3-MYB genes in the genome of Morinda officinalis and classified them into 32 subgroups based on phylogenetic comparison with Arabidopsis thaliana. The lack of recent whole-genome duplication events in M.officinalis may be the reason for the relatively few members of the R2R3-MYB family. We also further analyzed the physical and chemical characteristics, conserved motifs, gene structure, and chromosomal location. Gene duplication events found 21 fragment duplication pairs and five tandem duplication event R2R3-MYB genes in M.officinalis may also affect gene family expansion. Based on phylogenetic analysis, cis-element analysis, co-expression analysis and RT-qPCR, we concluded that MoMYB33 might modulate flavonol levels by regulating the expression of 4-coumarate-CoA ligase Mo4CL2, chalcone isomerase MoCHI3, and flavonol synthase MoFLS4/11/12. MoMYB33 and AtMYB111 showed the highest similarity of 79% and may be involved in flavonol synthase networks by the STRING database. Moreover, we also identified MoMYB genes that respond to methyl Jasmonate (MeJA) and abscisic acid (ABA) stress by RT-qPCR.ConclusionsThis study offers a thorough comprehension of R2R3-MYB in M.officinalis, which lays the foundation for the regulation of flavonol synthesis and the response of MoMYB genes to phytohormones in M.officinalis.

Drought stress-responsive abscisic acid and salicylic acid crosstalk with the phenylpropanoid pathway in soybean seeds.

Crosstalk between hormones and secondary metabolites regulates the interactions between plants and stress. However, little is known about the effects of hormone crosstalk on the concentration of flavonoids in seeds. In this study, we identified abscisic acid (ABA) as a negative regulator of flavonoid accumulation in soybean seeds under drought-stress conditions. Alterations in flavonoid accumulation at several intensities of water stress, followed by a recovery period, were measured during the soybean seed-filling stage. Low soil moisture (SM 10%) significantly decreased the total flavonoid content in seeds. The decline in flavonoid content was proportional to the severity of drought stress and was dependent on the activities of phenylalanine ammonia-lyase (PAL) and chalcone synthase (CHS), two key phenylpropanoid pathway enzymes. The expression of phenylalanine ammonia-lyase 1 (GmPAL1), chalcone isomerase 1A (GmCHI1A), and chalcone synthase 8 (GmCHS8) was associated with phenolic and flavonoid accumulation in soybean seeds of plants subjected to drought stress. Interestingly, the expression levels of GmCHS8 were highly correlated with flavonoid levels under drought stress and water recovery conditions. Cinnamic acid, which is a biosynthesis precursor shared by both phenylpropanoid metabolism and salicylic acid (SA) biosynthesis, decreased under drought stress conditions. Notably, exogenous ABA suppressed the expression of GmPAL1, which encodes the first rate-limiting enzyme in the phenylpropanoid biosynthesis pathway and affects downstream products such as SA and flavonoids. In conclusion, drought stress altered the phenylpropanoid-derived compounds, at least with regard to flavonoid and SA accumulation in seeds, which was regulated by antagonistic interactions with ABA.

Effects of 5-Aminolevulinic Acid (5-ALA) on Physicochemical Characteristics and Growth of Pomegranate (Punica granatum L.)

The pomegranate is one of the most essential crop fruits in the world. 5-Aminolevulinic acid (ALA) regulates the growth and development of 5-year-old pomegranate. However, for plenty of pome crops, conventional information on the physio-chemical characteristics underlying 5-ALA is limited. Therefore, in this study, we applied four different concentrations of 5-ALA treatments (0 mg L−1, 10 mg L−1, 20 mg L−1, 50 mg L−1, and 100 mg L−1), where 0 mg L−1 was considered as a control group, to evaluate the effects of 5-ALA on the physiochemical characteristics of pomegranates. Our results showed that maximal photochemical efficiency (FV/FM), photosystem (ΦPSII), and photochemical quenching (qP) increased at concentrations of 50 mg L−1 and 100 mg L−1 compared with controls. Anthocyanin contents were elevated by 2.27% and 1.33% at the 5-ALA concentrations of 50 mg L−1 and 100 mg L−1. Furthermore, qRT-PCRs of the DEGs, such as punica granatum chalcone synthase (PgCHS), chalcone isomerase (PgCHI), flavanone 3-hydroxylase (PgF3H), dihydroflavonol 4-reductase (PgDFR), anthocyanidin synthase (PgANS), and ultrafine-grained (PgUFG), showed up-regulations, except for chalcone isomerase (PgCHI), after 5-ALA treatments. The fresh weight of the fruit and the weight of the grains were elevated under 50 mg L−1 and 100 mg L−1 concentrations, and both the fresh weight of the fruit and the grain weight were higher than controls. Total sugar (TS) increased by 8.49% and 24.99%, total soluble solids (TSS) increased by 2.02% and 6.07%, soluble proteins increased by 1.16% and 1.15%, and the pH level of juice increased by 0.12% and 0.19%, respectively. In addition, the contents of ascorbic acid, total phenols, and total flavonoids increased by 24.18%, 2.53%, and 1.29%, respectively, compared with controls. Taken together, the antioxidant activities of SOD and POD also increased by 13.33% and 11.95% at concentrations of 100 mg L−1. Our results show that concentrations of 5-ALA treatments at 50 mg L−1 and 100 mg L−1 will be beneficial for crop cultivation.

Elicitation of flavonoid biosynthesis in cell suspension cultures of Haplophyllum virgatum by sodium nitroprusside

Plant cell suspension culture, along with elicitor application, is a suitable technique to obtain large amounts of bioactive compounds. Haplophyllum virgatum is an Iranian endemic plant species. Sodium nitroprusside (SNP) is widely used as a nitric oxide (NO) donor in studies on plants to investigate the physiological roles of NO. Here, the physiological responses were investigated in cell suspension cultures of H. virgatum in the presence of different concentrations of SNP (0, 100, 150, and 200 µM) at various time points (0, 8, 12, 24, 48, 72, and 168 h). The transcript levels of two flavonoid biosynthetic enzymes, including chalcone synthase (CHS) and chalcone isomerase (CHI), and an important transcription factor (R2R3-MYB), were measured in the SNP-treated cells. The content of rutin (the main flavonoid in the Rutaceae family) was also evaluated. Nitric oxide significantly decreased the hydrogen peroxide and malondialdehyde contents by increasing the proline and enzymatic and non-enzymatic antioxidants in the treated cells. Meanwhile, NO significantly elicited flavonoid production, including rutin. These results highlight the effects of NO on flavonoid biosynthesis in H. virgatum suspension cells, probably through gene expression regulation in and upstream of the flavonoid biosynthetic pathway.

Cloning, Identification, and Functional Analysis of the Chalcone Isomerase Gene from Astragalus sinicus.

Astragalus sinicus is an important winter-growing cover crop. It is widely utilized, not only as a cover crop for its benefits in fertilizing the soil but also as a landscape ground cover plant. Anthocyanins are involved in the pigmentation of plants in leaves and flowers, which is a crucial characteristic trait for A. sinicus. The formation of anthocyanins depends significantly on the enzyme chalcone isomerase (CHI). However, research on the CHI gene of A. sinicus remains unexplored. The rapid amplification of cDNA ends (RACE) approach was used in this research to clone the CHI sequence from A. sinicus (AsiCHI). The expression profiles of the AsiCHI gene in multiple tissues of A. sinicus were subsequently examined by qRT-PCR (Quantitative Real-Time PCR). Furthermore, the function of the AsiCHI was identified by the performance of ectopic expression in Arabidopsis (Arabidopsis thaliana). The outcomes revealed that the full-length cDNA of the AsiCHI gene (GeneBank: OQ870547) measured 972 bp in length and included an open reading frame of 660 bp. The encoded protein contains 219 amino acids with a molecular weight of 24.14 kDa and a theoretical isoelectric point of 5.11. In addition, the remarkable similarity between the AsiCHI protein and the CHI proteins of other Astragalus species was demonstrated by the sequence alignment and phylogenetic analysis. Moreover, the highest expression level of AsiCHI was observed in leaves and showed a positive correlation with anthocyanin content. The functional analysis further revealed that the overexpression of AsiCHI enhanced the anthocyanidin accumulation in the transgenic lines. This study provided a better understanding of AsiCHI and elucidated its role in anthocyanin production.

Full-length transcriptome analysis provides insights into flavonoid biosynthesis in Ranunculus japonicus.

Ranunculus japonicus Thunb. is a traditional Chinese herb. Plants in the genus Ranunculus are generally rich in flavonoids, which have antibacterial, anti-infective, and other pharmacological effects. However, owing to the lack of reference genomes, little is known about the flavonoid biosynthetic pathway in R. japonicus. In this study, PacBio isoform sequencing (PacBio iso-seq) and DNA nanoball sequencing (DNB-seq) were combined to build a full-length transcriptome database for three different tissues of R. japonicus. A total of 395,402 full-length transcripts were obtained, of which 308,474 were successfully annotated. A Kyoto Encyclopedia of Genes and Genomes analysis identified 29 differentially expressed genes encoding nine key enzymes for flavonoid biosynthesis. Correlation analysis indicated that flavanone 3-hydroxylase and flavonol synthase genes might have key roles in the accumulation of flavonoid substances in the different tissues of R. japonicus. The structures of chalcone synthase and chalcone isomerase enzymes were spatially modeled. Reverse-transcription quantitative PCR was used to verify gene expression levels of key enzymes associated with flavonoid biosynthesis. In addition, 22 MYB transcription factors involved in flavonoid biosynthesis and phenylpropanoid biosynthesis were discovered. The reliable transcriptomic data from this study provide genetic information about R. japonicus as well as insights into the molecular mechanism of flavonoid biosynthesis. The results also provide a basis for developing the medicinal value R. japonicus. This article is protected by copyright. All rights reserved.

The temporal changes of pigments content and key enzyme activities during autumnal turning period of Pistacia chinensis bunge

In this study, the temporal regularity of pigments and key enzyme intermediates of Pistacia chinensis Bunge in the color-changing period was investigated to provide a theoretical basis for exploring the mechanism of leaf discoloration. The pigment content and activities of key enzymes of P. chinensis during leaf discoloration were investigated. The correlation between leaf discoloration and environmental factors (temperature, relative humidity, light) was also analyzed. During the color change, the chlorophyll content decreased, while no significant change in the carotenoid content was observed. The anthocyanin content significantly increased in the middle of the period of color change. The ratios of carotenoids/chlorophyll and anthocyanins/chlorophyll showed an upward trend during the period of color change. The lightness parameter (L) and hue parameter (B) of P. chinensis Bunge leaves showed a fluctuating tendency, reaching the highest value at the beginning of color conversion. The hue parameter (A) showed an upward trend at the color conversion stage. The 5-aminolevulinic acid (ALA) and porphobilinogen (PBG) values showed an upward-downward-upward trend. The contents of ALA and PBG at the end of the color transformation were 2.01 times and 2.88 times higher than those at the beginning. The activity of phenylalaninammo-nialyase increased during the color change period. Chalcone isomerase and chalcone synthase first increased, then declined, reaching their highest level in the middle of color conversion, 261.0 u/g and 157.3 u/g, respectively. Although the activities of both enzymes declined at the end of the color conversion, they were higher than at the beginning of the color change. Anthocyanin content was negatively correlated with temperature, relative humidity, day length, and chalcone isomerase, whereas it was positively correlated with phenylalaninammo-nialyase. The results revealed the reasons for the discoloration of P. chinensis leaves in autumn and thus should be considered when exploring the mechanism of color-changing plants and performing color-changing plant applications.