Search

Abstract Ziziphi Spinosae Semen (ZSS) is the first choice for the treatment of insomnia. This research aimed to reveal the spatial distribution of identifying quality markers of ZSS and to illustrate the metabolite quality characteristics of this herbal medicine. Here, we performed a matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) in situ to detect and image 33 metabolites in ZSS, including three saponins, six flavonoids, four alkaloids, eight fatty acids, and 12 amino acids. The MALDI images of the metabolites clearly showed the heterogeneous spatial distribution in different regions of ZSS tissues, such as the cotyledon, endosperm, and radicle. The distribution area of two saponins, six flavonoids, and three alkaloids increased significantly after the fried processing of ZSS. Based on the ion images, samples with different processing technologies were distinguished unambiguously by the pattern recognition method of orthogonal partial least squares discrimination analysis (OPLS-DA). Simultaneously, 23 major influencing components exerting higher ion intensities were identified as the potential quality markers of ZSS. Results obtained in the current research demonstrate that the processing of ZSS changes its content and distribution of the medicinal components. The analysis of MALDI-MSI provides a novel MS-based molecular imaging approach to investigate and monitor traditional medicinal plants.

IntroductionEndophytic fungi can promote secondary metabolite accumulation in medicinal plants. Previously, we observed that the culture filtrate of Fusarium solani CL105 promoted flavonoid production in Scutellaria baicalensis calli. However, the active ingredients and mechanisms associated with this secondary metabolite accumulation remain unclear.MethodsThis study evaluates the effects of different elicitors from the culture filtrate of F. solani CL105 namely, exopolysaccharide (EPS), exoprotein (EP), and other parts (OP), on the flavonoid production in S. baicalensis calli by HPLC. Subsequently, the underlying mechanism of EPS induced flavonoid production in S. baicalensis calli was revealed by transcriptomics and RT-PCR.Results and discussionThe results indicated a significant increase in flavonoid production in S. baicalensis calli following treatment with EPS. Baicalin (1.40 fold), wogonoside (1.91 fold), and wogonin (2.76 fold) were most significantly up-regulated compared with the control. Transcriptome analysis further revealed up-regulation of key enzyme genes (CHS, CHI, FNS, and F6H) involved in flavonoid synthesis after 5 days of EPS treatment. Moreover, the expression of GA2ox and CYP707A—genes involved in gibberellin acid (GA) and abscisic acid biosynthesis (ABA), respectively—were significantly up-regulated. The expression levels of certain transcription factors, including MYB3, MYB8, and MYB13, were also significantly higher than in controls. Our results indicated that EPS was a main active elicitor involved in promoting flavonoid production in S. baicalensis calli. We postulated that EPS might stimulate the expression of MYB3, MYB8, MYB13, GA2ox, and CYP707A, leading to markedly upregulated CHS, CHI, FNS, and F6H expression levels, ultimately promoting flavonoid synthesis. This study provides a novel avenue for large-scale in vitro production of flavonoids in S. baicalensis.

Pinelliae Rhizoma (PR), a highly esteemed traditional Chinese medicinal herb, is widely applied in clinical settings due to its diverse pharmacological effects, including antitussive, expectorant, antiemetic, sedative-hypnotic, and antitumor activities. Pinellia ternata exhibits morphological variation in its leaves, with types resembling peach, bamboo, and willow leaves. However, the chemical composition differences among the corresponding rhizomes of these leaf phenotypes remain unelucidated. This pioneering research employed Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging (MALDI-MSI) to conduct the in situ identification and spatial profiling of 35 PR metabolites in PR, comprising 12 alkaloids, 4 organic acids, 12 amino acids, 5 flavonoids, 1 sterol, and 1 anthraquinone. Our findings revealed distinct spatial distribution patterns of secondary metabolites within the rhizome tissues of varying leaf types. Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA) effectively differentiated between rhizomes associated with different leaf morphologies. Furthermore, this study identified five potential differential biomarkers—methylophiopogonanone B, inosine, cytidine, adenine, and leucine/isoleucine—that elucidate the biochemical distinctions among leaf types. The precise tissue-specific localization of these secondary metabolites offers compelling insights into the specialized accumulation of bioactive compounds in medicinal plants, thereby enhancing our comprehension of PR’s therapeutic potential.

Bupleurum is a kind of medicinal plant that has made a great contribution to human health because of the presence of bioactive metabolites: Bupleurum saikosaponins and flavonoids. Despite their importance, it has been a challenge to visually characterize the spatial distribution of these metabolites in situ within the plant tissue, which is essential for assessing the quality of Bupleurum. The development of a new technology to identify and evaluate the quality of medicinal plants is therefore necessary. Here, the spatial distribution and quality characteristics of metabolites of three Bupleurum species: Bupleurum smithii (BS), Bupleurum marginatum var. stenophyllum (BM), and Bupleurum chinense (BC) were characterized by Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI). Twenty-nine metabolites, including saikosaponins, non-saikosaponins, and compounds from the saikosaponin synthesis pathway, were characterized. Some of these were successfully localized and visualized in the transverse section of roots. In these Bupleurum species, twelve saikosaponins, five non-saikosaponins, and five saikosaponin synthesis pathway compounds were detected. Twenty-two major influencing components, which exhibit higher ion intensities in higher quality samples, were identified as potential quality markers of Bupleurum. The final outcome indicates that BC has superior quality compared to BS and BM. MALDI-MSI has effectively distinguished the quality of these Bupleurum species, providing an intuitive and effective marker for the quality control of medicinal plants.

Apocynum venetum L. is a natural fiber and medicinal plant species with significant economic value. Jasmonic acid is an endogenous growth regulatory substance present in higher plants that participate in plant growth, development, and defense. As important endogenous single-stranded RNA molecules, microRNA (miRNA) plays an important role in the post-transcriptional regulation of plant genes. A combination of miRNA and mRNA sequencing techniques was used to systematically identify the methyl jasmonate miRNAs and mRNAs in A. venetum. Up to 135 conserved and 26 species-specific miRNAs have been identified in A. venetum. These miRNAs mainly target genes that encode transcription factors and enzymes. The expression levels of 23 miRNAs, including miR398 and miR482, significantly changed after MeJA treatment. A total of 1778 genes were differentially expressed under MeJA treatment, of which 825 were upregulated and 953 were downregulated. The main biological processes enriched in these differentially expressed genes were redox balance, secondary metabolism, photosynthesis, and plant hormone signal transduction. Joint analysis of the miRNAs and mRNA revealed that MeJA-responsive miRNAs function by forming regulatory modules, including miR398-CSD, miR482-NBS-LRR, miR156-SPL10, and miR164-NAC056, which further regulate multiple biological processes, including redox balance, disease resistance, and morphogenesis in A. venetum. This study provides important information to understand the biological roles of miRNAs in A. venetum.

R2R3-MYB transcription factors (TFs) participate in the modulation of plant development, secondary metabolism, and responses to environmental stresses. Ammopiptanthus nanus, a leguminous dryland shrub, tolerates a high degree of environmental stress, including drought and low-temperature stress. The systematic identification, structural analysis, evolutionary analysis, and gene profiling of R2R3-MYB TFs under cold and osmotic stress in A. nanus were performed. Up to 137 R2R3-MYB TFs were identified and clustered into nine clades, with most A. nanus R2R3-MYB members belonging to clade VIII. Tandem and segmental duplication events drove the expansion of the A. nanus R2R3-MYB family. Expression profiling revealed that multiple R2R3-MYB genes significantly changed under osmotic and cold stress conditions. MiR858 and miR159 targeted 88 R2R3-MYB genes. AnaMYB87, an miR858-targeted clade VIII R2R3-MYB TF, was up-regulated under both osmotic and cold stress. A transient expression assay in apples showed that the overexpression of AnaMYB87 promoted anthocyanin accumulation. A luciferase reporter assay in tobacco demonstrated that AnaMYB87 positively affected the transactivation of the dihydroflavonol reductase gene, indicating that the miR858-MYB87 module mediates anthocyanin accumulation under osmotic stress by regulating the dihydroflavonol reductase gene in A. nanus. This study provides new data to understand the roles of R2R3-MYB in plant stress responses.

Piptanthus nepalensis (Hooker) Sweet is a semi deciduous or deciduous shrub belonging to the genus Piptanthus, Leguminosae. P. nepalensis has been used as a folk medicinal herb in Nepal and was cultivated all over the world as an ornamental plant. In the present study, we sequenced the entire genome of the chloroplast of P. nepalensis. The total length of the chloroplast genome in P. nepalensis is 152,195 bp, including a large single-copy region of 82,048 bp, a small single-copy region of 17,675 bp, and a pair of inverted repeats regions of 26,236 bp. The overall guanine-cytosine (GC) content of the genome was 36.7%. There are 131 genes in the chloroplast genome of P. nepalensis, including 85 protein-coding genes, 8 rRNA genes and 38 tRNA genes. Phylogenetic analysis showed that P. nepalensis is closely related to Maackia floribunda.

Sophora davidii (Franch.) Pavol. is a deciduous or evergreen shrubs belonging to the genus Sophora, Fabaceae. The roots of S. davidii have been traditionally used as a medicinal herb in China to clear internal heat, relieve sore throat, and reduce swelling. Here we sequenced the whole genome of the chloroplast of S. davidii. The complete length of the chloroplast genome in S. davidii is 153,584 bp, containing a large single-copy region of 83,930 bp, a small single-copy region of 15,008 bp, and a pair of inverted repeats regions of 25,823 bp. The total guanine-cytosine (GC) percentage of the chloroplast genome was 36.7%. A total of 131 genes were annotated from the chloroplast genome of S. davidii, including 85 protein-coding genes, 8 rRNA genes and 38 tRNA genes. The phylogenetic analysis showed that S. davidii is closely related to the other three species of genus Sophora.

Astragalus membranaceus is an important medicinal plant widely cultivated in East Asia. MicroRNAs (miRNAs) are endogenous regulatory molecules that play essential roles in plant growth, development, and the response to environmental stresses. Cold is one of the key environmental factors affecting the yield and quality of A. membranaceus, and miRNAs may mediate the gene regulation network under cold stress in A. membranaceus. To identify miRNAs and reveal their functions in cold stress response in A. membranaceus, small RNA sequencing was conducted followed by bioinformatics analysis, and quantitative real time PCR (qRT-PCR) analysis was performed to profile the expression of miRNAs under cold stress. A total of 168 conserved miRNAs belonging to 34 families and 14 putative non-conserved miRNAs were identified. Many miRNA targets were predicted and these targets were involved in diversified regulatory and metabolic pathways. By using qRT-PCR, 27 miRNAs were found to be responsive to cold stress, including 4 cold stress-induced and 17 cold-repressed conserved miRNAs, and 6 cold-induced non-conserved miRNAs. These cold-responsive miRNAs probably mediate the response to cold stress by regulating development, hormone signaling, defense, redox homeostasis, and secondary metabolism in A. membranaceus. These cold-corresponsive miRNAs may be used as the candidate genes in further molecular breeding for improving cold tolerance of A. membranaceus.

Powdery mildew, caused by the biotrophic parasitic fungus Blumeria graminis f. sp. tritici (Bgt), is a prevalent disease in many wheat (Triticum aestivum L.)-producing regions throughout the world. To reduce yield losses and avoid environmental pollution caused by fungicide application, growing resistant cultivars is the preferred means for managing wheat powdery mildew. 'Zhongmai 155', a commercial winter wheat cultivar released in 2012, was resistant to 92 of the 115 Bgt isolates originating from northern China. Using segregating F2 and F2:3 populations derived from Zhongmai 155 × 'Han 4564' cross, genetic analysis indicated that a single dominant resistance gene, tentatively designated PmZ155, was responsible for the resistance of Zhongmai 155 to the Bgt isolate E09. The gene was subsequently localized on chromosome 5DS on the basis of the results of molecular marker analysis. The flanking markers SCAR203 and Xcfd8 are linked to gene PmZ155 at genetic distances of 0.3 and 4.9 cM, respectively, and were physically mapped to the deletion bin 5DS-1-0-0.63; therefore, PmZ155 is located in this region of chromosome 5DS and shares the same molecular markers as Pm2. However, Zhongmai 155 differed from Ulka/8*Cc (CI 14118), which carries gene Pm2 on chromosome 5DS, in its reactions to 26 of 111 commonly tested isolates, of which 18 isolates were avirulent on Zhongmai 155 but virulent on Ulka/8*Cc, while 8 isolates were virulent on Zhongmai 155 but avirulent on Ulka/8*Cc. Zhongmai 155 also differed from 'Tabasco' (carrying Pm48 on chromosome 5DS) in its reaction to 14 of 62 isolates. On the basis of its chromosome position, close linkage to the molecular markers Xcfd8 and SCAR203, but different responses to an array of Bgt isolates, it appears that PmZ155 is most likely an allele of locus Pm2. [ABSTRACT FROM AUTHOR]

This work aimed to identify the allelochemicals released by Glehnia littoralis Fr. Schmidt ex Miq. in soil and to study their allelopathic activity on Brassica pekinensis (Lour.) Rupr. In seedling tray assays, the rhizosphere soil from G. littoralis continuous monocropping drastically inhibited the growth of B. pekinensis. In Petri dish assays, Methanolic extracts from control soil (CK), soil under first G. littoralis cropping (FS), and continuous cropping (CS) were tested on germination and seedlings growth of B. pekinensis. These extracts inhibited the germination potential, germination rate, shoot height and root length of Brassica pekinensis. GC-MS analysis of the methanolic extracts revealed the presence of dibutyl phthalate (DBP) and 2,4-Di-tert-butylphenol (2,4-DTBP). These allelochemicals inhibited the seedling growth of B. pekinensis in Petri dish assays, and had deleterious effects on photosynthetic system and redox balance. Activities of peroxidase (POD) and catalase (CAT) increased, whereas, superoxide dismutase (SOD) decreased, chlorophyll content was lowered, but hydrogen peroxide (H2O2) and malondialdehyde (MDA) were increased. Our results suggested that under monocropping G. littoralis releases allelochemicals (DBP and 2,4-DTBP) into the soil. [ABSTRACT FROM AUTHOR]

Wheat powdery mildew (caused by Blumeria graminis f. sp. tritici) can be effectively managed by growing resistant cultivars. 'Liangxing 66' and 'Wennong 14' are the current winter wheat cultivars grown in northern China where powdery mildew is epidemic. Both cultivars have been demonstrated to carry single dominant genes for resistance to powdery mildew, tentatively designated PmLX66 and PmW14, on chromosome 5DS and share common linked markers with Pm2. Allelism tests were performed using a total of 15,657 plants of F2 segregating populations to determine the relationship between PmLX66, PmW14, and Pm2. All progeny from the crosses Liangxing 66 × 'Ulka/8*Chancellor' (Ulka/8*Cc), Wennong 14 × Ulka/8*Cc, and Liangxing 66 × Wennong 14 were resistant when tested with B. graminis f. sp. tritici isolate E20, indicating that PmLX66 and PmW14 are allelic to Pm2 and to each other. Liangxing 66 was resistant to 76.7% of the 60 B. graminis f. sp. tritici isolates from northern China, a slightly smaller proportion than Ulka/8*Cc (78.3%). However, Wennong 14 (85.0%) was more resistant against this set of B. graminis f. sp. tritici isolates than Ulka/8*Cc and Liangxing 66. Liangxing 66 and Wennong 14 differed from Ulka/8*Cc in respect to a number of B. graminis f. sp. tritici isolates. Based on these findings, PmLX66 and PmW14 are new alleles at the Pm2 locus. [ABSTRACT FROM AUTHOR]