Flavoprotein monooxygenases(FPMOs) and cytochrome P450(CYP450) oxygenases are pivotal monooxygenases in nature, catalyzing crucial redox reactions in diverse biological processes and contributing to the synthesis of highly complex natural products. While CYP450 enzymes have been extensively reported and studied, numerous FPMOs have also been discovered in past research endeavors, yet their classification, catalytic reactions, and catalytic mechanisms remain to be systematically analyzed. This paper comprehensively reviews the latest advancements in FPMOs research, initiating with a classification based on sequence similarities and distinct structural features. It delves into the catalytic characteristics of three subfamilies(FMO, BVMO, and NMO) within Class B FPMOs of plants, which are integral to biosynthetic pathways of natural products. Class B FPMOs encompass two canonical Rossmann fold motifs(FAD-binding GxGxxG and NADPH-binding GxGxxA), along with a central FMO recognition motif FxGxxxHxxxF/Y/W. These enzymes play a key role in regulating various metabolic routes and precisely modulate plant growth and development. Furthermore, the review summarizes the applications of Class B FPMOs of plants, showcasing through concrete examples their potential in synthesizing natural products such as auxins, indigo, and cyanogenic glycosides. These insights will broaden and deepen our understanding of FPMOs, fostering their transition from fundamental research to practical applications. More optimized biosynthetic pathways can be devised by leveraging FPMOs, conducive to the development of novel strategies and tools for agriculture, plant protection, natural product biosynthesis, and synthetic biology.
Biological Products/metabolism* ; Mixed Function Oxygenases/chemistry* ; Flavoproteins/chemistry* ; Plants/metabolism* ; Plant Proteins/chemistry* ; Cytochrome P-450 Enzyme System/genetics*

In this study, Saccharomyces cerevisiae R0 was used as the chassis cell to synthesize oleanolic acid from scratch through the heterologous expression of β-amyrin synthase(β-AS) from Glycyrrhiza uralensis, cytochrome P450 enzyme CYP716A154 from Catharanthus roseus, and cytochrome P450 reductase AtCPR from Arabidopsis thaliana. The engineered strain R1 achieved shake flask titres of 5.19 mg·L~(-1). By overexpressing enzymes in the pentose phosphate pathway(PPP)(ZWF1, GND1, TKL1, and TAL), the NADH kinase gene in the mitochondrial matrix(POS5), truncated 3-hydroxy-3-methylglutaryl-CoA reductase(tPgHMGR1) from Panax ginseng, and farnesyl diphosphate synthase gene(SmFPS) from Salvia miltiorrhiza, the precursor supply and intracellular reduced nicotinamide adenine dinucleotide phosphate(NADPH) supply were enhanced, resulting in an 11.4-fold increase in squalene yield and a 3.6-fold increase in oleanolic acid yield. Subsequently, increasing the copy number of the heterologous genes tPgHMGR1, β-AS, CYP716A154, and AtCPR promoted the metabolic flow towards the final product, oleanolic acid, and increased the yield by three times. Shake flask fermentation data showed that, by increasing the copy number, precursor supply, and intracellular NADPH supply, the final engineered strain R3 could achieve an oleanolic acid yield of 53.96 mg·L~(-1), which was 10 times higher than that of the control strain R1. This study not only laid the foundation for the green biosynthesis of oleanolic acid but also provided a reference for metabolic engineering research on other pentacyclic triterpenoids in S. cerevisiae.
Oleanolic Acid/biosynthesis* ; Saccharomyces cerevisiae/metabolism* ; Industrial Microbiology ; Microorganisms, Genetically-Modified/metabolism* ; Plants/enzymology* ; Fermentation ; Metabolic Engineering

The interactions between microorganisms and medicinal plants are crucial to the quality improvement of medicinal plants. Medicinal plants attract microorganisms to colonize by secreting specific compounds and provide niche and nutrient support for these microorganisms, with a symbiotic network formed. These microorganisms grow in the rhizosphere, phyllosphere, and endophytic tissues of plants and significantly improve the growth performance and medicinal component accumulation of medicinal plants by promoting nutrient uptake, enhancing disease resistance, and regulating the synthesis of secondary metabolites. Microorganisms are also widely used in the ecological planting of medicinal plants, and the growth conditions of medicinal plants are optimized by simulating the microbial effects in the natural environment. The interactions between microorganisms and medicinal plants not only significantly improve the yield and quality of medicinal plants but also enhance their geoherbalism, which is in line with the concept of green agriculture and eco-friendly development. This study reviewed the research results on the interactions between medicinal plants and microorganisms in recent years and focused on the analysis of the great potential of microorganisms in optimizing the growth environment of medicinal plants, regulating the accumulation of secondary metabolites, inducing systemic resistance, and promoting the ecological planting of medicinal plants. It provides a scientific basis for the research on the interactions between medicinal plants and microorganisms, the research and development of microbial agents, and the application of microorganisms in the ecological planting of medicinal plants and is of great significance for the quality improvement of medicinal plants and the green and sustainable development of TCM resources.
Plants, Medicinal/metabolism* ; Bacteria/genetics* ; Symbiosis

Constructing an efficient and easy-to-operate multigene expression system is currently a crucial part of plant genetic engineering. In this study, a fragment carrying three independent gene expression cassettes and the expression unit of the gene-silencing suppressor protein(RNA silencing suppressor 19 kDa protein, P19) simultaneously was designed and constructed. This fragment was cloned into the commonly used plant expression vector pCAMBIA300, and the plasmid pC1300-TP2-P19 was obtained. Each gene expression cassette consists of different promoters, fusion tags, and terminators. The target gene can be flexibly inserted into the corresponding site through enzymatic digestion and ligation or recombination and fused with different protein tags, which provides great convenience for subsequent detection. The enhanced green fluorescent protein(eGFP) reporter gene was individually constructed into each expression cassette to verify the feasibility of this vector system. The results of tobacco transient expression and laser-confocal microscopy showed that each expression cassette presented independent and normal expression. Meanwhile, the three key enzyme genes in the betanin synthesis pathway, BvCYP76AD, BvDODA1, and DbDOPA5GT, were constructed into the three expression cassettes. The results of tobacco transient expression phenotype, protein immunoblotting(Western blot), and chemical detection of product demonstrated that the three exogenous genes were highly expressed, and the target compound betanin was successfully produced. The above results indicated that the constructed multigene expression system for plants in this study was efficient and reliable and can achieve the co-transformation of multiple plant genes. It can provide a reliable vector platform for the analysis of plant natural product synthesis pathways, functional verification, and plant metabolic engineering.
Nicotiana/metabolism* ; Genetic Vectors/metabolism* ; Gene Expression Regulation, Plant ; Plant Proteins/metabolism* ; Plants, Genetically Modified/metabolism* ; Genetic Engineering/methods* ; Green Fluorescent Proteins/metabolism* ; Gene Expression

Panax species are mostly valuable medicinal plants. While some species' seeds are sensitive to dehydration, the dehydration tolerance of seeds from other Panax species remains unclear. The phospholipase D(PLD) gene plays an important role in plant responses to dehydration stress. However, the characteristics of the PLD gene family and their mechanisms of response to dehydration stress in seeds of Panax species with different dehydration tolerances are not well understood. This study used seeds from eight Panax species to measure the germination rates and PLD activity after dehydration and to analyze the correlation between dehydration tolerance and seed traits. Bioinformatics analysis was also conducted to characterize the PnPLD and PvPLD gene families and to evaluate their expression patterns under dehydration stress. The dehydration tolerance of Panax seeds was ranked from high to low as follows: P. ginseng, P. zingiberensis, P. quinquefolius, P. vietnamensis var. fuscidiscus, P. japonicus var. angustifolius, P. japonicus, P. notoginseng, and P. stipuleanatus. A significant negative correlation was found between dehydration tolerance and seed shape(three-dimensional variance), with flatter seeds exhibiting stronger dehydration tolerance(r=-0.792). Eighteen and nineteen PLD members were identified in P. notoginseng and P. vietnamensis var. fuscidiscus, respectively. These members were classified into five isoforms: α, β, γ, δ, and ζ. The gene structures, subcellular localization, physicochemical properties, and other characteristics of PnPLD and PvPLD were similar. Both promoters contained regulatory elements associated with plant growth and development, hormone responses, and both abiotic and biotic stress. During dehydration, the PLD enzyme activity in P. notoginseng seeds gradually increased as the water content decreased, whereas in P. vietnamensis var. fuscidiscus, PLD activity first decreased and then increased. The expression of PLDα and PLDδ in P. notoginseng seeds initially increased and then decreased, whereas in P. vietnamensis var. fuscidiscus, the expression of PLDα and PLDδ consistently decreased. In conclusion, the dehydration tolerance of Panax seeds showed a significant negative correlation with seed shape. The dehydration tolerance in P. vietnamensis var. fuscidiscus and dehydration sensitivity of P. notoginseng seeds may be related to differences in PLD enzyme activity and the expression of PLDα and PLDδ genes. This study provided the first systematic comparison of dehydration tolerance in Panax seeds and analyzed the causes of tolerance differences and the optimal water content for long-term storage at ultra-low temperatures, thus providing a theoretical basis for the short-term and ultra-low temperature long-term storage of medicinal plant seeds with varying dehydration tolerances.
Seeds/metabolism* ; Panax/physiology* ; Plant Proteins/metabolism* ; Gene Expression Regulation, Plant ; Phospholipase D/metabolism* ; Plants, Medicinal/enzymology* ; Germination ; Multigene Family ; Water/metabolism* ; Dehydration ; Phylogeny

Inflammatory bowel disease is a chronic, idiopathic, and recurrent gastrointestinal disorder with an unclear etiology and uncertain pathogenesis. Traditional treatment strategies rely on frequent administration of high doses of medication to reduce inflammation, whereas these approaches have limitations and may induce potential complications. Therefore, finding more effective and safe therapeutic drugs and methods is particularly important. Plant-derived exosome-like nanovesicles(PDELNs) are nano-sized vesicles with a lipid bilayer structure that are secreted by plant cells. The bioactive molecules contained within, such as lipids, proteins, and nucleic acids, can serve as information carriers, playing a role in the transmission of information and substances between cells and across species. PDELNs can carry and transfer their own bioactive substances or act as carriers for delivering other active components or drugs. Due to the high biocompatibility, low toxicity, and significant bioactivity, PDELNs have garnered widespread attention. Compared with other exosomes, PDELNs are not destroyed in the gastrointestinal tract when taken orally and can reach the intestines. This unique property makes PDELNs a promising oral nanodrug for treating intestinal diseases, showing great potential in this area. This article reviews recent research literature on PDELNs regarding the physicochemical characteristics, extraction and purification methods, functions, application characteristics and mechanisms in the treatment of intestinal diseases, and use as a carrier for treating intestinal diseases, aiming to provide a reference for the use of PDELNs in the treatment of intestinal diseases.
Humans ; Exosomes/metabolism* ; Animals ; Intestinal Diseases/metabolism* ; Plants/metabolism* ; Drug Carriers/chemistry* ; Drugs, Chinese Herbal/chemistry* ; Drug Delivery Systems ; Nanoparticles/chemistry*

The HDAs (a subfamily of histone deacetylases), a class of Zn²⁺-dependent histone deacetylases, are highly homologous to the reduced potassium dependency 3 (RPD3) in yeast. HDAs extensively regulate chromosome stability, gene transcription, and protein activity by catalyzing the removal of acetyl group from histone and non-histone lysine residues. HDA-mediated deacetylation is essential for plant growth, development, and responses to abiotic stress. We review the research progress in HDAs regarding the discovery, structures, classification, deacetylation process, and roles in regulating plant responses to abiotic stress. Furthermore, this paper prospects the future research on HDAs, aiming to provide theoretical support for the research on epigenetic regulation mediated by HDAs.
Histone Deacetylases/classification* ; Zinc/metabolism* ; Stress, Physiological/physiology* ; Plants/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*