Screening and validation of reference genes in Dracaena cochinchinensis using quantitative real-time PCR.

Dragon's blood, the red resin derived from the wounded Dracaena, is a precious traditional medicine used by different culture. Dracaena cochinchinensis is one of the main species of Dracaena, and is the endangered medicinal plants in China. The vulnerable status severely limits the medicinal value and wide application of dragon's blood. Therefore, it's essential to analyze the mechanisms that form dragon's blood in order to increase artificial production. To clarify the mechanisms forming dragon's blood, understanding gene expression in the flavonoid biosynthesis pathway is the foundation. However, reference genes of D. cochinchinensis haven't been analyzed. In this study, expression profiles of seven commonly used housekeeping genes (Actin, α-EF, UBC, ß-tubulin, 18S, GAPDH, His) were evaluated by using quantitative real-time PCR combined with the algorithms geNorm, NormFinder, BestKeeper, and RefFinder. On the basis of overall stability ranking, the best reference genes were the combinations ß-tubulin +UBC for wounded stems and α-EF +18S + Actin for different organs. Reliability of the recommended reference genes was validated by normalizing relative expression of two key enzyme genes PAL1 and CHI1 in the flavonoid biosynthesis pathway. The results provide a foundation to study gene expression in future research on D. cochinchinensis or other Dracaena.

First Report of Sclerotinia Rot Caused by Sclerotinia sclerotiorum on Artemisia capillaris in China.

Artemisia capillaris (Asteraceae) is an annual herb found in ˃10 provinces in China. It is cultivated on ˃670 ha, with annual production around 2,500 tons. Its shoot is used in traditional Chinese medicine (Liu et al. 2021). From April to May 2023, Sclerotinia rot symptoms were seen at the Institute of Medicinal Plant Development (40.04°N, 116.28°E), Beijing, China. Disease incidence was up to 10% in the field through investigation of 300 plants. Initial symptoms were irregular tan-brown lesions (0.5 to 5.0 mm) that expended to circumferential necrosis on the roots and basal stem, aerial mycelia and sclerotia were developed on them. The leaves and stem tips were withered and droopy in severe cases. Twelve symptomatic primary roots of 12 plants from two sites were cut into 5 × 5 mm pieces, surface sterilized with 75% ethanol for 30 s and 5% NaClO for 60 s, rinsed with distilled water for three times, dried with sterile filter paper, put on potato dextrose agar (PDA), and incubated at 25°C in the dark for 2 days. Two Sclerotinia-like isolates were obtained using the hyphaltip method. White aerial mycelia were sparse and appressed for isolate YC1-3 and dense for isolate YC1-7. After incubated at 25°C in the dark for 15 days, 10 to 25 sclerotia were developed near the colony margin. Sclerotia of isolate YC1-3 were 1.0 to 3.9 × 1.2 to 4.5 (mean 1.8 × 2.2) mm (n = 60), ovoid or arc-shaped. Sclerotia of isolate YC1-7 were 1.5 to 3.4 × 2.7 to 9.2 (mean 2.3 × 4.3) mm (n = 60), ovoid, dumbbell shaped or curved. The isolates were identified as Sclerotinia sclerotiorum based on morphology (Maas 1998). To further identify the pathogens, molecular identification was performed with isolates YC1-3 and YC1-7. DNA of the two isolates were extracted by the cetyltrimethylammonium bromide (CTAB) method. Polymerase chain reaction was performed with primers ITS1/ITS4 for the internal transcribed spacer (ITS) region (Choi et al. 2020; White et al. 1990) and primers G3PDHfor/G3PDHrev for the glyceraldehyde 3-phosphate dehydrogenase (G3PDH) gene (Garfinkel. 2021). BLAST search analysis revealed that the ITS sequence (GenBank OR229758 and OR229762) was ≥99% similar to S. sclerotiorum (MN099281, MZ379265, KX781301, etc.), and the G3PDH sequence (OR778388 and OR761975) was too (MZ493894, JQ036048, OQ790148, etc.). Phylogenetic trees were computed with ITS and G3PDH sequences using the Maximum Likelihood in MEGA 11. Nine two-month-old seedlings of A. capillaris were used to test pathogenicity. The epidermis layer of each primary root was slightly wounded (2 × 2 mm, 1 mm deep) using a sterile dissecting blade. Three plants were inoculated with mycelial plugs (5 mm in diameter) of YC1-3 and YC1-7 that cultured on PDA for 7 days. Control plants were inoculated with sterile PDA plugs. All seedlings were then incubated at 25oC and 90% relative humidity. After isolate YC1-7 inoculation 3 days and isolate YC1-3 inoculation 5 days, inoculated roots had symptoms like those in the field, controls had no symptoms. S. sclerotiorum was consistently re-isolated from diseased roots, fulfilling Koch's postulates. Diseases caused by S. sclerotiorum have been reported threatens several important economical crops (Marin and Peres 2020; Guan et al. 2022). To our knowledge, this is the first report of S. sclerotiorum causes Sclerotinia rot on A. capillaris. To avoid of significant economic losses, it is urgent to establish an effective disease-management strategy.

Biosynthesis and Pharmacological Activities of Flavonoids, Triterpene Saponins and Polysaccharides Derived from Astragalus membranaceus.

Astragalus membranaceus (A. membranaceus), a well-known traditional herbal medicine, has been widely used in ailments for more than 2000 years. The main bioactive compounds including flavonoids, triterpene saponins and polysaccharides obtained from A. membranaceus have shown a wide range of biological activities and pharmacological effects. These bioactive compounds have a significant role in protecting the liver, immunomodulation, anticancer, antidiabetic, antiviral, antiinflammatory, antioxidant and anti-cardiovascular activities. The flavonoids are initially synthesized through the phenylpropanoid pathway, followed by catalysis with corresponding enzymes, while the triterpenoid saponins, especially astragalosides, are synthesized through the universal upstream pathways of mevalonate (MVA) and methylerythritol phosphate (MEP), and the downstream pathway of triterpenoid skeleton formation and modification. Moreover, the Astragalus polysaccharide (APS) possesses multiple pharmacological activities. In this review, we comprehensively discussed the biosynthesis pathway of flavonoids and triterpenoid saponins, and the structural features of polysaccharides in A. membranaceus. We further systematically summarized the pharmacological effects of bioactive ingredients in A. membranaceus, which laid the foundation for the development of clinical candidate agents. Finally, we proposed potential strategies of heterologous biosynthesis to improve the industrialized production and sustainable supply of natural products with pharmacological activities from A. membranaceus, thereby providing an important guide for their future development trend.

Apiaceae Medicinal Plants in China: A Review of Traditional Uses, Phytochemistry, Bolting and Flowering (BF), and BF Control Methods.

Apiaceae plants have been widely used in traditional Chinese medicine (TCM) for the removing dampness, relieving superficies, and dispelling cold, etc. In order to exploit potential applications as well as improve the yield and quality of Apiaceae medicinal plants (AMPs), the traditional use, modern pharmacological use, phytochemistry, effect of bolting and flowering (BF), and approaches for controlling BF were summarized. Currently, about 228 AMPs have been recorded as TCMs, with 6 medicinal parts, 79 traditional uses, 62 modern pharmacological uses, and 5 main kinds of metabolites. Three different degrees (i.e., significantly affected, affected to some extent, and not significantly affected) could be classed based on the yield and quality. Although the BF of some plants (e.g., Angelica sinensis) could be effectively controlled by standard cultivation techniques, the mechanism of BF has not yet been systemically revealed. This review will provide useful references for the reasonable exploration and high-quality production of AMPs.

Combined Metabolome and Transcriptome Analysis Highlights the Host's Influence on Cistanche deserticola Metabolite Accumulation.

The medicinal plant Cistanche deserticola Ma (Orobanchaceae) is a holoparasitic angiosperm that takes life-essential materials from Haloxylon ammodendron (C. A. Mey.) Bunge (Amaranthaceae) roots. Although many experiments have been conducted to improve the quality of C. deserticola, little attention has been paid to the host's influence on metabolite accumulation. In this study, transcriptomic and metabolomic analyses were performed to unveil the host's role in C. deserticola's metabolite accumulation, especially of phenylethanoid glycosides (PhGs). The results indicate that parasitism by C. deserticola causes significant changes in H. ammodendron roots in relation to metabolites and genes linked to phenylalanine metabolism, tryptophan metabolism and phenylpropanoid biosynthesis pathways, which provide precursors for PhGs. Correlation analysis of genes and metabolites further confirms that C. deserticola's parasitism affects PhG biosynthesis in H. ammodendron roots. Then we found specific upregulation of glycosyltransferases in haustoria which connect the parasites and hosts. It was shown that C. deserticola absorbs PhG precursors from the host and that glycosylation takes place in the haustorium. We mainly discuss how the host resists C. deserticola parasitism and how this medicinal parasite exploits its unfavorable position and takes advantage of host-derived metabolites. Our study highlights that the status of the host plant affects not only the production but also the quality of Cistanches Herba, which provides a practical direction for medicinal plant cultivation.

[Anxiolytic and antidepressant effects of agarwood inhalation and its mechanism].

This study used m-chloropheniperazine(MCPP) and chronic unforeseeable mild stress(CUMS) to induce the rat models of anxiety and depression, respectively. The behaviors of rats were observed by the open field test(OFT), light-dark exploration test(LDE), tail suspension test(TST), and forced swimming test(FST), and the antidepressant and anxiolytic effects of agarwood essential oil(AEO), agarwood fragrant powder(AFP), and agarwood line incense(ALI) were explored. The enzyme-linked immunosorbent assay(ELISA) was used to determine the levels of 5-hydroxytryptamine(5-HT), glutamic acid(Glu), and γ-aminobutyric acid(GABA_A) in the hippocampal area. The Western blot assay was used to determine the protein expression levels of glutamate receptor 1(GluR1) and vesicular glutamate transporter type 1(VGluT1), exploring the anxiolytic and antidepressant mechanism of agarwood inhalation. The results showed that compared with the anxiety model group, the AEO, AFP, and ALI groups decreased the total distance(P<0.05), decreased the velocity of movements(P<0.05), prolonged the immobile time(P<0.05), and reduced the distance and velocity of the rat model of anxiety in the dark box(P<0.05). Compared with the depression model group, the AEO, AFP, and ALI groups increased the total distance and average velocity(P<0.05), reduced the immobile time(P<0.05), and reduced the forced swimming and tail suspension time(P<0.05). In terms of transmitter regulation, the AEO, AFP, and ALI groups decreased the level of Glu in the rat model of anxiety(P<0.05) and increased the levels of GABA_A and 5-HT(P<0.05), while the AEO, AFP, and ALI groups all increased the level of 5-HT in the rat model of depression(P<0.05) and decreased the levels of GABA_A and Glu(P<0.05). At the same time, the AEO, AFP, and ALI groups all increased the protein expression levels of GluR1 and VGluT1 in the hippocampus of the rat models of anxiety and depression(P<0.05). In conclusion, AEO, AFP, and ALI exert anxiolytic and antidepressant effects, and the mechanism might be related to the regulation of the neurotransmitter and the protein expression of GluR1 and VGluT1 in the hippocampus.

Bupleurum chinense exerts a mild antipyretic effect on LPS-induced pyrexia rats involving inhibition of peripheral TNF-α production.

ETHNOPHARMACOLOGICAL RELEVANCE: Bupleuri Radix, the dried roots of Bupleurum chinense DC. (BC) or Bupleurum scorzonerifolium Willd., is one of the most frequently used traditional Chinese medicines. As the species in Xiao-Chai-Hu decoction, BC has been used as an antipyretic medicine with a long history. However, its antipyretic characteristics and underlying mechanism(s) remain unclear. AIM OF THE STUDY: To elucidate the antipyretic characteristics and mechanism(s) of BC used in its traditional way. METHODS: The water extract of BC (BCE) was prepared according to the traditional decocting mode. Murine fever and endotoxemia models were induced by intravenous injection of lipopolysaccharide (LPS). In vitro complement activation assay and the levels of TNF-α, IL-6, IL-1ß, and C5a were determined by ELISA. RESULTS: BCE exerted a confirmed but mild antipyretic effect on LPS-induced fever of rat. In vitro, it significantly lowered LPS-elevated TNF-α in the supernatant of rat complete blood cells and THP-1 cells, but failed to decrease IL-6 and IL-1ß. In murine endotoxemia models, BCE markedly decreased serum TNF-α, but had no impact on IL-6 and IL-1ß. BCE also restricted complement activation in vitro and in vivo. Nevertheless, the mixture of saikosaponin A and D could not suppress supernatant TNF-α of monocytes and serum TNF-α of endotoxemia mice. CONCLUSIONS: The present study dissects the peripheral mechanism for the antipyretic effect of BC used in the traditional way. Our findings indicate that BCE directly suppresses monocyte-produced TNF-α, thus decreasing circulating TNF-α, which may be responsible for its mild but confirmed antipyretic action.

Structure and histochemistry of the stem of Dracaena cambodiana Pierre ex Gagnep.

Dracaena cambodiana Pierre ex Gagnep is an important plant resource for producing dragon's blood and one of most popular ornamental trees in China. For a better understanding of the physiological function of the stem, the structural characteristics and main substance histological location of the stems of D. cambodiana were studied. The structural characteristics of the different developmental stages of stems of D. cambodiana were observed and described detailly. And then a schematic diagram of the mature stem was created. Histochemical staining showed that two kinds of polysaccharides distributed in parenchymal cells. Saponins distributed mainly in ground tissue and phenolic compounds distributed mainly in the thick cell walls. An abundant of calcium oxalate raphide bundles were identified in cortex and primary tissue. Finally, the role of the above results in the taxonomy of Dracaena species and in their strong adaptability was discussed.

Agarwood essential oil inhalation exerts antianxiety and antidepressant effects via the regulation of Glu/GABA system homeostasis.

Depression and anxiety are common diseases that endanger the physical and mental health of individuals. Agarwood incense inhalation has been used as a traditional Chinese medicine for relaxation and to improve sleep for centuries. In a previous study by the authors it was demonstrated that agarwood essential oil (AEO) injection exerted anxiolytic and antidepressant effects. Therefore the present study further investigated the anxiolytic and antidepressant effects of AEO inhalation on anxiolytic mice induced by M-chlorophenylpiperazine and depressive mice induced by chronic unpredictable mild stress. The results demonstrated that AEO exerted a significant anxiolytic effect, whereby autonomous movements were inhibited during the light dark exploration test and open field test. Furthermore, the tail suspension test and the forced swimming test demonstrated that AEO also exerted an antidepressant effect, whereby the immobility times were decreased. Moreover, AEO was determined to increase the levels of 5-hydroxytryptamine, γ-aminobutyric acid (GABA) A receptor (GABAA) and glutamate (Glu) in anxiolytic mice and inhibit the levels of GABAA and Glu in depressive mice. Further investigations into how AEO affected the Glu/GABA system demonstrated that AEO markedly increased the protein expression levels of GABA transaminase (GABAT), glutamate metabotropic receptor 5 (GRM5), glutamate ionotropic receptor AMPA type subunit 1 (GluR1) and vesicular glutamate transporter 1 (VGluT1). Furthermore, AEO reduced the expression levels of GABAT, glutamate ionotropic receptor NMDA type subunit 2B and GRM5, and enhanced the expression levels of GluR1 and VGluT1. These results demonstrated that AEO potentially possesses antianxiety and antidepressant properties. The present study determined that the mechanism was related to the regulation of Glu/GABA neurotransmitter system homeostasis.

A comprehensive review on traditional and modern research of the genus Bupleurum (Bupleurum L., Apiaceae) in recent 10 years.

ETHNOPHARMACOLOGICAL RELEVANCE: The genus Bupleurum (family Apiaceae), comprising approximately 248 accepted species, is widely distributed and used in China, Japan, India, Central Asia, North Africa and some European countries as traditional herbal medicines. Certain species have been reported to have significant therapeutic effects in fever, inflammatory disorders, cancer, gastric ulcer, virus infection and other diseases. AIM OF THE REVIEW: we performed a comprehensive review of the ten-year research progress in phytochemistry, pharmacology, toxicity, along with bibliometrics research of the genus Bupleurum, aiming to identify knowledge gaps for future research. MATERIALS AND METHODS: All the literatures are retrieved from library and electronic sources including Web of Science, PubMed, Elsevier, Google Scholar, CNKI and Baidu Scholar. These papers cover studies of the traditional use, phytochemistry, pharmacology, and toxicology of the genus Bupleurum. RESULTS: There is a long history of using the genus Bupleurum in traditional herbal medicine that dated back to over 2000 years ago. Twenty-five species and 8 varieties with 3 variants within this genus have been reported to be effective to treat fever, pain, liver disease, inflammation, thoracolumbar pain, irregular menstruation and rectal prolapse. The main phytochemicals found in these plants are triterpene saponins, volatile oil, flavonoid, lignans, and polysaccharides. Many of these compounds have also been shown to have anti-inflammatory, anti-tumor, antimicrobial, immunoregulation, neuroregulation, hepatoprotective and antidiabetic activities. Meanwhile, improper usage of Bupleurum may induce cytotoxic effects, and polyacetylenes may be the main poisonous compounds. CONCLUSIONS: This article summarized recent findings about Bupleurum research from many different aspects. While a small number of Bupleurum species have been investigated through modern pharmacology methods, there are still major knowledge gaps due to inadequate studies and ambiguous findings. Future research could focus on more specific phytochemistry studies combined with mechanistic analysis to provide better guidance to utilize Bupleurum as medicinal resources.

Identification and characterization of a novel Cytorhabdovirus associated with goji berry (Lycium barbarum L.) crinkle disease.

Goji berry (Lycium barbarum L.) is a traditional Chinese herbal medicinal plant that is extensively cultivated in the arid and semiarid regions of northwest China. In this study, a novel cytorhabdovirus, tentatively named "goji cytorhabdovirus A (GCVA)," was identified from the goji berry plant exhibiting leaf crinkle symptoms through high-throughput sequencing (HTS). GCVA contains a linear, negative sense single-stranded RNA genome of 14,812 nucleotides and encodes six open reading frames in the order of 3' leader-N-P-P4-M-G-L-5' trailer. The genome of GCVA shares the highest nucleotide (nt) identity of 65.80% (16% query coverage) with yerba mate virus A (YmVA) (NC_076472). The N and L proteins also share low amino acid (aa) identities (<35.42 and < 41.23%, respectively) with known cytorhabdoviruses. Typical features of the viruses in the genus Cytorhabdovirus include a highly conserved consensus sequence in the intergenic regions and extensive complementation of the 5' non-coding trailer and the 3' leader. These features were also found in GCVA. These data in combination with a phylogenetic analysis that was based on the aa sequences of the N and L proteins support the proposal that GCVA is a new species in the genus Cytorhabdovirus.

[Two new sesquiterpenes in Qi-nan Aquilariae Lignum Resinatum].

This study aimed to investigate the chemical constituents of supercritical extract from Qi-nan Aquilariae Lignum Resinatum by silica gel column chromatography, thin-layer chromatography, and semi-preparative high-performance liquid chromatography. One new elemane-type and one new eudesmane-type sesquiterpene compounds were isolated from the extract, and their structures were identified by MS, UV, IR, NMR, and ECD spectroscopic techniques, and named aquqinanol C(1) and aquqinanol D(2). Both compounds are novel compounds. The neuroprotective effect of the compounds on CORT-induced PC12 cell damage was determined in vitro. The results showed that compounds 1 and 2 exhibited a certain protective effect against CORT-induced damage in PC12 cells.

Integrated metabolomics and transcriptomics analysis of roots of Bupleurum chinense and B. scorzonerifolium, two sources of medicinal Chaihu.

Radix Bupleuri (Chaihu in Chinese) is a traditional Chinese medicine commonly used to treat colds and fevers. The root metabolome and transcriptome of two cultivars of B. chinense (BCYC and BCZC) and one of B. scorzonerifolium (BSHC) were determined and analyzed. Compared with BSHC, 135 and 194 differential metabolites were identified in BCYC and BCZC, respectively, which were mainly fatty acyls, organooxygen metabolites. A total of 163 differential metabolites were obtained between BCYC and BCZC, including phenolic acids and lipids. Compared with BSHC, 6557 and 5621 differential expression genes (DEGs) were found in BCYC and BSHC, respectively, which were annotated into biosynthesis of unsaturated fatty acid and fatty acid metabolism. A total of 4,880 DEGs existed between the two cultivars of B. chinense. The abundance of flavonoids in B. scorzonerifolium was higher than that of B. chinense, with the latter having higher saikosaponin A and saikosaponin D than the former. Pinobanksin was the most major flavonoid which differ between the two cultivars of B. chinense. The expression of chalcone synthase gene was dramatically differential, which had a positive correlation with the biosynthesis of pinobanksin. The present study laid a foundation for further research on biosynthesis of flavonoids and terpenoids of Bupleurum L.

A chromosome-level genome assembly for Dracaena cochinchinensis reveals the molecular basis of its longevity and formation of dragon's blood.

Dracaena, a remarkably long-lived and slowly maturing species of plant, is world famous for its ability to produce dragon's blood, a precious traditional medicine used by different cultures since ancient times. However, there is no detailed and high-quality genome available for this species at present; thus, the molecular mechanisms that underlie its important traits are largely unknown. These factors seriously limit the protection and regeneration of this rare and endangered plant resource. Here, we sequenced and assembled the genome of Dracaena cochinchinensis at the chromosome level. The D. cochinchinensis genome covers 1.21 Gb with a scaffold N50 of 50.06 Mb and encodes 31 619 predicted protein-coding genes. Analysis showed that D. cochinchinensis has undergone two whole-genome duplications and two bursts of long terminal repeat insertions. The expansion of two gene classes, cis-zeatin O-glucosyltransferase and small auxin upregulated RNA, were found to account for its longevity and slow growth. Two transcription factors (bHLH and MYB) were found to be core regulators of the flavonoid biosynthesis pathway, and reactive oxygen species were identified as the specific signaling molecules responsible for the injury-induced formation of dragon's blood. Our study provides high-quality genomic information relating to D. cochinchinensis and significant insight into the molecular mechanisms responsible for its longevity and formation of dragon's blood. These findings will facilitate resource protection and sustainable utilization of Dracaena.

Comparative transcriptome analysis reveals different defence responses during the early stage of wounding stress in Chi-Nan germplasm and ordinary Aquilaria sinensis.

BACKGROUND: Agarwood is a valuable Chinese medicinal herb and spice that is produced from wounded Aquilaria spp., is widely used in Southeast Asia and is highly traded on the market. The lack of highly responsive Aquilaria lines has seriously restricted agarwood yield and the development of its industry. In this article, a comparative transcriptome analysis was carried out between ordinary A. sinensis and Chi-Nan germplasm, which is a kind of A. sinensis tree with high agarwood-producing capacity in response to wounding stress, to elucidate the molecular mechanism underlying wounding stress in different A. sinensis germplasm resources and to help identify and breed high agarwood-producing strains. RESULTS: A total of 2427 and 1153 differentially expressed genes (DEGs) were detected in wounded ordinary A. sinensis and Chi-Nan germplasm compared with the control groups, respectively. KEGG enrichment analysis revealed that genes participating in starch metabolism, secondary metabolism and plant hormone signal transduction might play major roles in the early regulation of wound stress. 86 DEGs related to oxygen metabolism, JA pathway and sesquiterpene biosynthesis were identified. The majority of the expression of these genes was differentially induced between two germplasm resources under wounding stress. 13 candidate genes related to defence and sesquiterpene biosynthesis were obtained by WGCNA. Furthermore, the expression pattern of genes were verified by qRT-PCR. The candidate genes expression levels were higher in Chi-Nan germplasm than that in ordinary A. sinensis during early stage of wounding stress, which may play important roles in regulating high agarwood-producing capacity in Chi-Nan germplasm. CONCLUSIONS: Compared with A. sinensis, Chi-Nan germplasm invoked different biological processes in response to wounding stress. The genes related to defence signals and sesquiterepene biosynthesis pathway were induced to expression differentially between two germplasm resources. A total of 13 candidate genes were identified, which may correlate with high agarwood-producting capacity in Chi-Nan germplasm during the early stage of wounding stress. These genes will contribute to the development of functional molecular markers and the rapid breeding highly of responsive Aquilaria lines.

Chemical Composition and Potential Properties in Mental Illness (Anxiety, Depression and Insomnia) of Agarwood Essential Oil: A Review.

As a valuable medicinal herb and spice, agarwood is widely used in the fields of daily chemistry, traditional medicine, religion and literary collection. It mainly contains sesquiterpenes and 2-(2-phenylethyl)chromones, which are often used to soothe the body and mind, relieve anxiety, act as an antidepressant and treat insomnia and other mental disorders, presenting a good calming effect. This paper reviews the chemical composition of the essential oils of different sources of agarwood, as well as the progress of research on the sedative and tranquilizing pharmacological activity and mechanism of action of agarwood essential oil (AEO), and then analyzes the current problems of AEO research and its application prospects in the treatment of mental diseases.

Genome-wide investigation and expression analysis of the AP2/ERF family for selection of agarwood-related genes in Aquilaria sinensis (Lour.) Gilg.

Aquilaria sinensis is an important non-timber tree species for producing high-value agarwood, which is widely used as a traditional medicine and incense. Agarwood is the product of Aquilaria trees in response to injury and fungal infection. The APETALA2/ethylene responsive factor (AP2/ERF) transcription factors (TFs) play important roles in plant stress responses and metabolite biosynthesis. In this study, 119 AsAP2/ERF genes were identified from the A. sinensis genome and divided into ERF, AP2, RAV, and Soloist subfamilies. Their conserved motif, gene structure, chromosomal localization, and subcellular localization were characterized. A stress/defense-related ERF-associated amphiphilic repression (EAR) motif and an EDLL motif were identified. Moreover, 11 genes that were highly expressed in the agarwood layer in response to whole-tree agarwood induction technique (Agar-Wit) treatment were chosen, and their expression levels in response to methyl jasmonate (MeJA), salicylic acid (SA), or salt treatment were further analyzed using the quantitative real time PCR (qRT-PCR). Among the 11 genes, eight belonged to subgroup B-3. All 11 genes were significantly upregulated under salt treatment, while eight genes were significantly induced by both MeJA and SA. In addition, the gene clusters containing these upregulated genes on chromosomes were observed. The results obtained from this research not only provide useful information for understanding the functions of AP2/ERF genes in A. sinensis but also identify candidate genes and gene clusters to dissect their regulatory roles in agarwood formation for future research.

Genetic relationship and source species identification of 58 Qi-Nan germplasms of Aquilaria species in China that easily form agarwood.

Recently, Qi-Nan germplasm, the germplasm of Aquilaria species that easily forms agarwood, has been widely cultivated in Guangdong and Hainan Provinces in China. Since the morphological characteristics of Qi-Nan germplasm are similar to those of Aquilaria species and germplasm is bred by grafting, it is difficult to determine the source species of this germplasm by traditional taxonomic characteristics. In this study, we performed a DNA barcoding analysis of 58 major Qi-Nan germplasms as well as Aquilaria sinensis, A. yunnanensis, A. crassna, A. malaccensis and A. hirta with 5 primers (nuclear gene internal transcribed spacer 2 (ITS2) and the chloroplast genes matK, trnH-psbA, rbcL and trnL-trnF). This field survey in the Qi-Nan germplasm plantations in Guangdong and Hainan Provinces aimed to accurately identify the source species of Qi-Nan germplasm. According to the results, ITS2 and matK showed the most variability and the highest divergence at all genetic distances. This ITS2+matK combination, screened for with TaxonDNA analysis, showed the highest success rate in species identification of the Qi-Nan germplasm. Clustering in the phylogenetic trees constructed with Bayesian inference and maximum likelihood indicated that the Qi-Nan germplasm was most closely related to A. sinensis and more distantly related to A. yunnanensis, A. crassna, A. malaccensis and A. hirta. Therefore, this study determined that the source species of the Qi-Nan germplasm is A. sinensis.

Programmed cell death might involve in progress of wounding induced agarwood formation in stems of Aquilaria sinensis.

Agarwood, a non-timber fragrant wood, is derived from wounded Aquilaria trees (Thymelaeaceae) and is widely used in traditional medicine, incense and perfume. Agarwood-like substances and programmed cell death (PCD) can be induced by wounding signals in the suspension cells and aerial roots of Aquilaria sinensis. In this study, the dynamic process of wound-induced agarwood formation in stems of A. sinensis was observed, and the occurrence of PCD was synchronously detected using techniques such as 4',6-diamidino-2-phenylindole and dUTP nick-end labeling staining. The results showed that the wounding was a induce signal for agarwood resin formation, meanwhile might induce PCD. Interxylary phloem and xylem ray were the main sites of agarwood resin formation and PCD occurrence. There might be a relationship between the spatiotemporal pattern of PCD and agarwood resin formation: more severe PCD corresponded to a higher rate of resin formation but a shorter resin formation time; conversely, slower PCD progression corresponded to a lower rate of resin formation but a longer resin formation time. Our findings are the first to demonstrate that PCD might occur in the process of wound-induced agarwood formation at the tree level, and the spatiotemporal pattern is closely related to the formation of agarwood resin. This study provides valuable insight for further studies on the relationship between PCD and agarwood formation. HIGHLIGHTS: Programmed cell death (PCD) might occur in the process of wound-induced agarwood formation at the tree level. Interxylary phloem and xylem ray were the main sites of agarwood resin formation and PCD occurrence. Spatiotemporal pattern of PCD might have a strong impact on agarwood resin formation.

Temporal Dynamics of Rhizosphere Communities Across the Life Cycle of Panax notoginseng.

Rhizosphere microbiome promotes plant growth; however, the succession of rhizosphere microbial community during the growth stages of perennial medicinal plant Panax notoginseng (P. notoginseng) is still unclear. Here, amplicon sequencing was performed to assess the succession characteristics of rhizosphere microbiomes during developmental stages. Results showed that bacterial and fungal communities were mainly shaped by the development stages. The microbial α-diversities first increased and then decreased with plant growth and the variation in microbial composition was active at the 3-year root growth (3YR) stage. The variation trend of cross-domain co-occurrence network complexity was similar to that of α-diversities. Cross-domain nodes decreased at the 3YR stage and fungal nodes increased at the 3YR stage. This study provided a detailed and systematic survey of rhizosphere microbiomes during the growth stages of P. notoginseng. The findings revealed that the development stages of P. notoginseng drove the temporal dynamics of rhizosphere communities. This study helps in harnessing the power of microbiomes to evaluate herbal medicine growth and provides valuable information to guide the microbial breeding of medical plants.