Stem-leaf saponins from Panax notoginseng (SLSP) comprise numerous PPD-type saponins with diverse pharmacological properties; however, their role in Parkinson's disease (PD), characterized by microglia-mediated neuroinflammation, remains unclear. This study evaluated the effects of SLSP on suppressing microglia-driven neuroinflammation in experimental PD models, including the 1-methyl-4-phenylpyridinium (MPTP)-induced mouse model and lipopolysaccharide (LPS)-stimulated BV-2 microglia. Our findings revealed that SLSP mitigated behavioral impairments and excessive microglial activation in models of PD, including MPTP-treated mice. Additionally, SLSP inhibited the upregulation of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX2) and attenuated the phosphorylation of PI3K, protein kinase B (AKT), nuclear factor-κB (NFκB), and inhibitor of NFκB protein α (IκBα) both in vivo and in vitro. Moreover, SLSP suppressed the production of inflammatory markers such as interleukin (IL)-1β, IL-6, and tumor necrosis factor alpha (TNF-α) in LPS-stimulated BV-2 cells. Notably, the P2Y2R agonist partially reversed the inhibitory effects of SLSP in LPS-treated BV-2 cells. These results suggest that SLSP inhibit microglia-mediated neuroinflammation in experimental PD models, likely through the P2Y2R/PI3K/AKT/NFκB signaling pathway. These novel findings indicate that SLSP may offer therapeutic potential for PD by attenuating microglia-mediated neuroinflammation.
Animals ; Panax notoginseng/chemistry* ; Saponins/pharmacology* ; Microglia/immunology* ; Mice ; NF-kappa B/immunology* ; Signal Transduction/drug effects* ; Proto-Oncogene Proteins c-akt/immunology* ; Phosphatidylinositol 3-Kinases/genetics* ; Male ; Parkinson Disease/immunology* ; Mice, Inbred C57BL ; Disease Models, Animal ; Plant Leaves/chemistry* ; Neuroinflammatory Diseases/drug therapy* ; Humans

Benzylisoquinoline alkaloids (BIAs) are a structurally diverse group of plant metabolites renowned for their pharmacological properties. However, sustainable sources for these compounds remain limited. Consequently, researchers are focusing on elucidating BIA biosynthetic pathways and genes to explore alternative sources using synthetic biology approaches. CYP80B, a family of cytochrome P450 (CYP450) enzymes, plays a crucial role in BIA biosynthesis. Previously reported CYP80Bs are known to catalyze the 3'-hydroxylation of (S)-N-methylcoclaurine, with the N-methyl group essential for catalytic activity. In this study, we successfully cloned a full-length CYP80B gene (StCYP80B) from Stephania tetrandra (S. tetrandra) and identified its function using a yeast heterologous expression system. Both in vivo yeast feeding and in vitro enzyme analysis demonstrated that StCYP80B could catalyze N-methylcoclaurine and coclaurine into their respective 3'-hydroxylated products. Notably, StCYP80B exhibited an expanded substrate selectivity compared to previously reported wild-type CYP80Bs, as it did not require an N-methyl group for hydroxylase activity. Furthermore, StCYP80B displayed a clear preference for the (S)-configuration. Co-expression of StCYP80B with the CYP450 reductases (CPRs, StCPR1, and StCPR2), also cloned from S. tetrandra, significantly enhanced the catalytic activity towards (S)-coclaurine. Site-directed mutagenesis of StCYP80B revealed that the residue H205 is crucial for coclaurine catalysis. Additionally, StCYP80B exhibited tissue-specific expression in plants. This study provides new genetic resources for the biosynthesis of BIAs and further elucidates their synthetic pathway in natural plant systems.
Cytochrome P-450 Enzyme System/chemistry* ; Benzylisoquinolines/chemistry* ; Hydroxylation ; Plant Proteins/chemistry* ; Alkaloids/metabolism* ; Stephania tetrandra/genetics*

Sjögren's syndrome (SS) is an autoimmune disease characterized primarily by oral and periocular dryness. Astragalus-Salvia (AS) and Ophiopogon-Dendrobium (OD) represent two frequently utilized herb pairs in SS treatment. While the combination of AS-OD herb pairs demonstrates clinical efficacy in alleviating SS symptoms, its underlying mechanism remains unclear. This investigation sought to assess the therapeutic effects and elucidate the potential mechanisms of AS-OD in non-obese diabetic (NOD)/Ltj mice with SS. The study utilized NOD/Ltj mice as SS models, administering AS-OD treatment for 10 weeks at doses of 113.1, 226.2, and 339.3 mg·d^-1·20 g^-1. Results demonstrated that AS-OD improved SS symptoms, evidenced by enhanced salivary flow rate, decreased anti-SSA/Ro and anti-SSB/La antibody levels, increased swimming duration, and reduced lactate (LA) and blood urea nitrogen (BUN) levels in NOD/Ltj mice. AS-OD reduced lymphocyte infiltration, enhanced Aquaporin-5 (AQP5) expression in the submandibular gland, decreased inflammatory cytokine levels in the submandibular gland, and reduced the T helper type 17/regulatory T lymphocyte (Th17/Treg) cell ratio in the spleen. Transcriptomic and proteomic analyses indicated AS-OD's involvement in regulating phosphatidylinositol-3-kinase/protein kinase B (PI3K/AKT) and Janus kinase 3/signal transducer and activator of transcription 3 (JAK1/STAT3) pathways, with inhibitory effects validated in both NOD/Ltj mice submandibular gland and A-253 cells. Furthermore, AS-OD enhanced cell viability and reduced A-253 cell apoptosis through the PI3K/AKT pathway. In A-253 cells, AS-OD reduced inflammatory cytokine levels, CXC chemokine ligand 9/10 (CXCL9/10), and T-cell chemotaxis by inhibiting the JAK1/STAT3 pathway. AS-OD mitigates SS by suppressing inflammation and immune responses through the PI3K/AKT and JAK1/STAT3 pathways.
Animals ; STAT3 Transcription Factor/genetics* ; Sjogren's Syndrome/immunology* ; Mice, Inbred NOD ; Proto-Oncogene Proteins c-akt/genetics* ; Phosphatidylinositol 3-Kinases/genetics* ; Mice ; Drugs, Chinese Herbal/administration & dosage* ; Signal Transduction/drug effects* ; Janus Kinase 1/genetics* ; Humans ; Female ; Astragalus Plant/chemistry* ; Male

Transcriptional regulation based on transcription factors is an effective regulatory method widely used in microbial cell factories. Currently, few naturally transcriptional regulatory elements have been discovered from Saccharomyces cerevisiae and applied. Moreover, the discovered elements cannot meet the demand for specific metabolic regulation of exogenous compounds due to the high background expression or narrow dynamic ranges. There are abundant transcriptional regulatory elements in plants. However, the sequences and functions of most elements have not been fully characterized and optimized. Particularly, the applications of these elements in microbial cell factories are still in the infancy stage. In this study, natural regulatory elements from Medicago truncatula were selected, including the transcription factors MtTASR2 and MtTASR3, along with their associated promoter P_roHMGR1, for functional characterization and engineering modification. We constructed an inducible transcriptional regulation tool and applied it in the regulation of heterologous β-carotene synthesis in S. cerevisiae, which increased the β-carotene production by 7.31 folds compared with the original strain. This study demonstrates that plant-derived transcriptional regulatory elements can be used to regulate the expression of multiple genes in S. cerevisiae, providing new strategies and ideas for the specific regulation and application of these elements in microbial cell factories.
Medicago truncatula/metabolism* ; Saccharomyces cerevisiae/metabolism* ; Transcription Factors/genetics* ; beta Carotene/biosynthesis* ; Promoter Regions, Genetic/genetics* ; Gene Expression Regulation, Plant ; Metabolic Engineering/methods* ; Regulatory Elements, Transcriptional/genetics* ; Plant Proteins/genetics*

Autophagy is an evolutionarily conserved self-degradation process in eukaryotes. It not only plays a role in plant growth and development but also is involved in plant responses to biotic and abiotic stresses. Plants can initiate autophagy to degrade the surplus or damaged cytoplasmic materials and organelles, thus coping with abiotic and biotic stresses. The initiation of autophagy depends on autophagy-related genes (ATGs). The transcription factors can directly bind to the promoters of ATGs to activate autophagy and regulate their transcriptional levels and post-translational modifications. Furthermore, ATGs can directly or indirectly interact with plant hormones to regulate plant responses to stresses. When plants are exposed to salinity, drought, extreme temperatures, nutrient deficiencies, and pathogen stress, ATGs are significantly induced, which enhances the autophagy activity to facilitate the degradation of the denatured and misfolded proteins, thereby enhancing plant tolerance to adversity stresses. This article summarizes the discovery, structures, and classification of plant ATGs, reviews the research progress in the mechanisms of ATGs in plant responses to abiotic and biotic stresses, and prospects the future research directions. This review is expected to provide the genetic resources and a theoretical foundation for the genetic improvement of crops in responses to stress tolerance.
Autophagy/physiology* ; Stress, Physiological/genetics* ; Gene Expression Regulation, Plant ; Plants/metabolism* ; Transcription Factors/metabolism* ; Plant Proteins/genetics* ; Genes, Plant ; Plant Physiological Phenomena ; Droughts

Jasmonic acid (JA) is a common plant hormone with regulatory effects on plant growth and development. The jasmonate ZIM-domain (JAZ) proteins (JAZs), as key regulators in the JA signaling pathway, are involved in multiple biological processes such as anthocyanin accumulation, flowering time modulation, and secondary metabolite synthesis in plants. JAZs are essential components of many regulatory signaling networks. The JAZ genes, members of the plant-specific TIFY family, have been identified in the genomes of a variety of horticultural plants. Here, we summarized the research progress in the roles of JAZs in horticultural plants, aiming to give insights into the further study of the biological functions and regulatory networks of JAZ genes in plants.
Horticulture ; Repressor Proteins/metabolism* ; Plant Proteins/metabolism* ; Cyclopentanes/metabolism* ; Oxylipins/metabolism* ; Plants/metabolism* ; Plant Development

Sweet-tasting proteins demonstrate application potential in foods and beverages due to their high sweetness, low calorie, and non-toxicity. So far, eight natural sweet-tasting proteins have been obtained from natural plants. This paper briefs the sweetness properties of the eight proteins and the molecular mechanism of the sweetness, reviews the progress in the genetic engineering, heterologous expression, and molecular modification of three representative sweet-tasting proteins (monellin, brazzein, and thaumatin), and summarizes their expression yields in different hosts and sweetness properties. Lastly, this paper prospects the research, application, and industrial development of sweet-tasting proteins. This review provides a reference for further research and development of new proteinaceous sweeteners.
Plant Proteins/biosynthesis* ; Genetic Engineering/methods* ; Sweetening Agents/chemistry* ; Plants, Genetically Modified/metabolism*

Prunus mume is an ecologically and economically valuable plant with both medicinal and edible values. However, drought severely limits the promotion and cultivation of P. mume in the arid and semi-arid areas in northern China. In this study, we treated P. mume 'Meiren' with natural drought and then assessed photosynthetic and physiological indexes such as osmoregulatory substances, photosynthetic parameters, and antioxidant enzyme activities. Furthermore, we employed transcriptome sequencing to explore the internal regulatory mechanism of P. mume under drought stress. As the drought stress aggravated, the levels of chlorophyll a (Chla), chlorophyll b (Chlb), chlorophyll (a+b)[Chl(a+b)], and soluble protein (SP) in P. mume first elevated and then declined. The net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), maximum photochemical efficiency (Fv/Fm), effective photochemical quantum yield [Y(Ⅱ)], photochemical quenching (qP), and relative electron transport rate (ETR) all kept decreasing, while the levels of malondialdehyde, superoxide dismutase (SOD), peroxidase (POD), and osmoregulatory substances rose. Transcriptome sequencing revealed a total of 24 853 high-quality genes. Gene ontology (GO) enrichment showed that differentially expressed genes (DEGs) were the most under severe drought. Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis showed that the DEGs during the four drought periods were mainly involved in the biosynthesis of secondary metabolites, plant-pathogen interaction, plant hormone signal transduction, starch and sucrose metabolism, and mitogen-activated protein kinase signaling pathways. Furthermore, we identified 16 key genes associated with the drought tolerance of P. mume 'Meiren'. This study discovered that P. mume might up-regulate or down-regulate the expression of drought tolerance-related genes such as SUS, P5CS, LEA, SOD, POD, SOD1, TPPD, and TPPA via transcription factors like MYB, ERF, bHLH, NAC, and WRKY to promote the accumulation of osmoregulatory substances like sucrose and enhance the activities of antioxidant enzymes such as SOD and POD, thus reducing the harm of reactive oxygen species and protecting the structure and function of the membrane system under drought stress. The findings provide theoretical references for further exploration of candidate genes of P. mume in response to drought stress and breeding of drought-tolerant varieties.
Droughts ; Photosynthesis/physiology* ; Gene Expression Regulation, Plant ; Stress, Physiological/genetics* ; Prunus/genetics* ; Chlorophyll/metabolism* ; Plant Proteins/genetics*

Peanut, a major economic and oil crop known for the high protein and oil content, is extensively cultivated in China. Peanut plants have the ability to form nodules with rhizobia, where the nitrogenase converts atmospheric nitrogen into ammonia nitrogen that can be utilized by the plants. Analysis of nodule fixation is of positive significance for avoiding overapplication of chemical fertilizer and developing sustainable agriculture. In this study, AhNIGT1.2, a member of the NIGT family predominantly expressed in peanut nodules, was identified by bioinformatics analysis. Subsequent spatiotemporal expression analysis revealed that AhNIGT1.2 was highly expressed in nodules and showed significant responses to high nitrogen, low nitrogen, high phosphorus, low phosphorus, and rhizobia treatments. Histochemical staining indicated that the gene was primarily expressed in developing nodules and at the connection region between mature nodules and peanut roots. The fusion protein AhNIGT1.2-GFP was located in the nucleus of tobacco epidermal cells. The AhNIGT1.2-OE significantly increased the number of peanut nodules, while AhNIGT1.2-RNAi reduced the number of nodules, which suggested a positive regulatory role of AhNIGT1.2 in peanut nodulation. The AhNIGT1.2-OE in roots down-regulated the expression levels of NRT1.2, NRT2.4, NLP1, and NLP7, which indicated that AhNIGT1.2 influenced peanut nodulation by modulating nitrate transport and the expression of NLP genes. The transcriptome analysis of AhNIGT1.2-OE and control roots revealed that overexpressing AhNIGT1.2 significantly enriched the differentially expressed genes associated with nitrate response, nodulation factor pathway, enzymes for triterpene biosynthesis, and carotenoid biosynthesis. These findings suggest that AhNIGT1.2 play a key role in peanut nodulation by regulating nitrate transport and response and other related pathways. This study gives insights into the molecular mechanisms of nitrogen and phosphorus in regulating legume nodulation and nitrogen fixation, and sheds light on the development of legume crops that can efficiently fix nitrogen in high nitrogen environments.
Arachis/physiology* ; Nitrates/metabolism* ; Plant Proteins/physiology* ; Transcription Factors/metabolism* ; Plant Root Nodulation/physiology* ; Gene Expression Regulation, Plant ; Root Nodules, Plant/metabolism* ; Nitrogen Fixation

The protein kinase A/protein kinase G/protein kinase C-family (AGC kinase family) of eukaryotes is involved in regulating numerous biological processes. The 3-phosphoinositide- dependent protein kinase 1 (PDK1), is a conserved serine/threonine kinase in eukaryotes. To understand the roles of PDK1 homologous genes in cell death and immunity in tetraploid Nicotiana tabacum, the previuosly generated transgenic CRISPR/Cas9 lines, in which 5-7 alleles of the 4 homologous PDK1 genes (NtPDK1a/1b/1c/1d homologs) simultaneously knocked out, were used in this study. Our results showed that the hypersensitive response (HR) triggered by transient overexpression of active Pto (Pto^Y207D) or soybean GmMEKK1 was significantly delayed, whereas the resistance to Pseudomonas syrangae pv. tomato DC3000 (Pst DC3000) and tobacco mosaic virus (TMV) was significantly elevated in these partial knockout lines. The elevated resistance to Pst DC3000 and TMV was correlated with the elevated activation of NtMPK6, NtMPK3, and NtMPK4. Taken together, our results indicated that NtPDK1s play a positive role in cell death but a positive role in disease resistance, likely through negative regulation of the MAPK signaling cascade.
Nicotiana/virology* ; Disease Resistance/genetics* ; Plant Diseases/immunology* ; Plants, Genetically Modified/genetics* ; Gene Knockout Techniques ; Plant Proteins/genetics* ; CRISPR-Cas Systems ; Protein Serine-Threonine Kinases/genetics* ; 3-Phosphoinositide-Dependent Protein Kinases/genetics* ; Pyruvate Dehydrogenase Acetyl-Transferring Kinase ; Tobacco Mosaic Virus/pathogenicity*