Search Results (77)

Global warming has increased outbreaks of the tea pest Ectropis grisescens. However, how water and nitrogen management modulates tea plant resistance against this pest through induced volatile organic compounds (VOCs) remains unclear. This study aimed to (1) characterize how water–nitrogen interactions alter the composition of VOCs in fresh leaves of Camellia sinensis cv. Rougui, and (2) identify key VOCs that mediate repellence against E. grisescens. Using gas chromatography–mass spectrometry (GC–MS) and olfactometry under three water and three nitrogen levels, we found that nitrogen effects on VOCs were contingent on water status. Four terpenoids—(+)-dihydrocarvone, myrcene, linalool, and β-ocimene—and one green-leaf volatile ((E)-3-hexenoic acid) significantly repelled E. grisescens, whereas hexanoic acid, 3-oxo-, ethyl ester acted as an attractant. Mechanistically, low-water–moderate-nitrogen and high-water–high-nitrogen treatments reduced repellent terpenoids and increased attractant VOCs, thereby elevating pest preference. These results demonstrate that water–nitrogen coupling shifts the balance between repellent and attractant volatiles, providing a physiological basis for manipulating tea plant resistance through agronomic management. Full article

Marine-derived species of the genus Alternaria are widely distributed across diverse aquatic habitats, functioning as pathogens, endophytes, and saprophytes. These fungi are notable for their ability to produce structurally diverse secondary metabolites with potent bioactivities. Between 2003 and 2023, a total of 67 marine-derived Alternaria species were reported and investigated, collectively yielding 319 compounds. Most of these fungal isolates were from Chinese marine territories (53 species; ~79%), followed by isolates from Korea, Japan, India, Egypt, Saudi Arabia, and oceanic regions such as the Atlantic and Pacific. The fungal isolates were mainly obtained from marine plants (26 isolates) and marine animals (23 isolates), with additional sources including sediments (13) and seawater (3). Among the metabolites investigated in different screens, approximately 56% demonstrated measurable bioactivities, with anti-inflammatory (51 active compounds), antimicrobial (41 compounds), cytotoxic (39 compounds), and phytotoxic (52 compounds) activities being the most frequently reported. Additionally, compounds with antiparasitic, antidiabetic and antioxidant effects are reported. The chemical diversity of Alernaria-derived compounds spans multiple structural groups, including nitrogenous compounds, steroids, terpenoids, pyranones, quinones, and phenolics. Notably, compounds such as alternariol, alternariol monomethyl ether, and alternariol-9-methyl ether exhibit broad pharmacological potential, including antibacterial, antifungal, antiviral, immunomodulatory, and anticancer effects. Several metabolites also modulate cytokine production (e.g., IL-10, TNF-α), underscoring their relevance as immunomodulatory agents. Taken together, marine-derived Alternaria compounds represent a prolific and underexplored source of structurally and biologically diverse secondary metabolites with potential applications in drug discovery, agriculture, and biotechnology. This review provides an updated and comprehensive overview of the chemical and biological diversity of Alternaria metabolites reported over the past two decades, emphasizing their biomedical relevance and potential to inspire further research into their ecological functions, biosynthetic mechanisms, and industrial applications. Full article

Heavy metal (HM) contamination in agricultural soils poses a significant threat to soil health and plant productivity. This study investigates the impact of cadmium (Cd) and zinc (Zn) stress on tomato plants (Solanum lycopersicum) and explores the mitigation potential of microbial biostimulants (MBs), including arbuscular mycorrhizal fungi (AMF) and Pseudomonas fluorescens So_08 (PGPR), over a 52-day period using multi-omics approaches. Root exudate profiling revealed distinct metabolic changes under HM stress, which compromised soil–plant interactions. Cd stress reduced the secretion of phenylpropanoids (sum LogFC: −45.18), lipids (sum LogFC: −27.67), and isoprenoids (sum LogFC: −11–67), key metabolites in antioxidative defense, while also suppressing rhizosphere fungal populations. Conversely, Zn stress enhanced lipid exudation (such as sphingolipids and sterols, as sum LogFC of 8.72 and 9.99, respectively) to maintain membrane integrity and reshaped rhizobacterial communities. The MBs application mitigated HM-induced stress by enhancing specialized metabolite syntheses, including cinnamic acids, terpenoids, and flavonoids, which promoted crop resilience. MBs also reshaped microbial diversity, fostering beneficial species like Portibacter spp., Alkalitalea saponilacus under Cd stress, and stimulating rhizobacteria like Aggregatilinea spp. under Zn stress. Specifically, under Cd stress, bacterial diversity remained relatively stable, suggesting their resilience to Cd. However, fungal communities exhibited greater sensitivity, with a decline in diversity in Cd-treated soils and partial recovery when MBs were applied. Conversely, Zn stress caused decline in bacterial α-diversity, while fungal diversity was maintained, indicating that Zn acts as an ecological filter that suppresses sensitive bacterial taxa and favors Zn-tolerant fungal species. Multi-omics data integration combined with network analysis highlighted key features associated with improved nutrient availability and reduced HM toxicity under MB treatments, including metabolites and microbial taxa linked to sulfur cycling, nitrogen metabolism, and iron reduction pathways. These findings demonstrate that MBs can modulate plant metabolic responses and restore rhizosphere microbial communities under Cd and Zn stress, with PGPR showing broader metabolomic recovery effects and AMF influencing specific metabolite pathways. This study provides new insights into plant–microbe interactions in HM-contaminated environments, supporting the potential application of biostimulants for sustainable soil remediation and plant health improvement. Full article

High temperatures during grain filling degrade rice quality, yet the metabolite-level basis of varietal tolerance—particularly root contributions—remains unclear. We compared the heat-tolerant ‘Fusaotome’ and the widely grown ‘Akitakomachi’ under control and high-temperature conditions. Panicles and roots were sampled at heading and profiled by capillary electrophoresis–mass spectrometry (CE–MS), followed by PCA, univariate testing, and KEGG pathway analysis. PCA resolved treatment and cultivar differences in an organ-specific manner. In panicles, ‘Fusaotome’ showed 8 increased metabolites (≥1.5-fold) and 11 decreased (≤1/1.5), whereas ‘Akitakomachi’ showed 19 increases and 6 decreases (p < 0.05). In roots, 12 metabolites increased in ‘Fusaotome’ and 9 in ‘Akitakomachi’; no significant decreases were detected. Pathway analysis indicated activation in ‘Fusaotome’ panicles of tryptophan, nicotinate/nicotinamide, arginine/proline, glycolysis/TCA, pyruvate, and vitamin B6 pathways, while ‘Akitakomachi’ emphasized phenylpropanoid, isoquinoline alkaloid, caffeine, and ubiquinone/terpenoid–quinone biosynthesis. In roots, ‘Fusaotome’ prioritized phenylalanine/phenylpropanoid, aromatic amino acids, lysine degradation, branched-chain amino acids, glycerophospholipids, and alkaloids, whereas ‘Akitakomachi’ favored nitrogen- and antioxidant-related routes. Collectively, the tolerant cultivar maintained antioxidant capacity and energy supply while coordinating root–panicle metabolism, whereas the susceptible cultivar shifted toward secondary defenses. These signatures nominate candidate metabolic markers and targets for breeding and management to stabilize rice production under warming climates. Full article

Challenges significantly hinder the sustainable cultivation of tea chrysanthemum, leading to imbalances in soil nutrients, the accumulation of allelopathic phenolic acids, reduced enzymatic activity, and disruptions in rhizosphere microbial communities. To explore potential mitigation strategies, this study systematically evaluated the integrative effects of exogenous methyl jasmonate (MeJA, 0–400 (μmol L⁻¹)) on both soil environmental parameters and plant growth performance under continuous cropping conditions. The results revealed that treatment with 100 (μmol L⁻¹) MeJA significantly enhanced plant height, canopy width, flower number, and fresh flower weight. Concurrently, it improved soil organic matter content, the available nitrogen levels, and redox stability while increasing the activity of key enzymes, including polyphenol oxidase, urease, and catalase. Notably, this treatment markedly reduced the accumulation of allelopathic phenolic acids, such as p-hydroxybenzoic acid and vanillic acid. High-throughput sequencing further demonstrated that 100 (μmol L⁻¹) MeJA optimized the composition of soil microbial communities, increasing the abundance of beneficial taxa, such as nitrogen-fixing and phosphate-solubilizing bacteria, while suppressing pathogenic fungi. Metabolomic analysis showed that this concentration of MeJA activated stress-resistance metabolic pathways involving flavonoids and terpenoids while downregulating degradation-related processes, thereby supporting enhanced plant resilience at the metabolic level. Collectively, these findings demonstrate that an appropriate concentration of exogenous MeJA can effectively alleviate continuous cropping obstacles in Chrysanthemum morifolium, providing both theoretical insights and practical guidance for its eco-friendly and efficient cultivation. Full article

The escalating demand for rural domestic wastewater treatment necessitates environmentally sustainable and cost-effective technologies. This study investigated the enhancement of a micro/nano aeration biofilter (MABF) through electric field coupling (E-MABF), evaluating pollutant removal efficacy and associated bacterial community dynamics. The results showed that the electric field significantly enhanced removal efficiency with respect to total phosphorus (TP), phosphate (PO₄³⁻-P), ammonium nitrogen (NH₄⁺-N), and chemical oxygen demand (COD) (p < 0.05). The TP, PO₄³⁻-P, NH₄⁺-N, and COD removal efficiencies for E-MABF reached 89.79%, 88.69%, 57.29%, and 57.96%, significantly exceeding those of MABF (26.50%,33.41%, 35.49%, and 45.75%). Electric field application markedly altered bacterial diversity and community composition. Core phyla, including Pseudomonadota, Chloroflexota, and Cyanobacteriota, exhibited significant positive correlations with pollutant removal efficiencies, indicating electric field facilitation of functional bacterial enrichment. KEGG pathway analysis suggested that electric field stimulation potentially enhanced metabolic functions, particularly in terpenoid and polyketide metabolism, and xenobiotics biodegradation. The Mantel’s test and structural equation model identified dominant bacterial composition as the primary factor influencing pollutant removal, followed by microenvironmental indicators and bacterial diversity. These findings elucidate the mechanisms underpinning the electric field augmentation of micro/nano aeration biofilter performance and provide a foundation for future research. Full article

This study investigated individual/combined nitrogen (N) and potassium (K) deficiencies on ginseng root aroma using GC–MS metabolomics. Four treatments (normal supply, N deficiency (LN), K deficiency (LK), and dual deficiency (LNLK)) were analyzed. Deficiencies impaired growth, mineral accumulation, and induced oxidative stress, suppressing ginsenoside biosynthesis. From 1768 detected VOCs, 304 compounds (rOAV ≥ 1) significantly contributed to aroma. LN inhibited terpenoids (e.g., isoborneol) but upregulated sulfur compounds (e.g., di-2-propenyl tetrasulfide), intensifying pungency. LK enhanced sweet/woody notes (e.g., 2′-acetonaphthone) via flavonoid biosynthesis and toluene degradation. LNLK reduced esters (e.g., benzyl acetate) and terpenes, attenuating floral–balsamic nuances by coordinating aromatic degradation, glutathione metabolism, and ABC transporters. N–K nutrition dynamically shapes ginseng aroma by differentially regulating phenylpropanoid, terpenoid, and sulfur pathways, providing a foundation for precision fertilization and quality improvement. Full article

Hongqujiu, one of the three principal varieties of yellow wine, is a traditional fermented beverage originating from China that employs Hongqu as the fermentation agent. In this study, an untargeted metabolomics approach based on gas chromatography–mass spectrometry (GC-MS) and liquid chromatography–mass spectrometry (LC-MS) was applied to systematically analyze the volatile compounds (VOCs) and non-volatile compounds (NVCs) in Hongqujiu across different aging years for the first time. The analysis identified a total of 262 VOCs and 2564 NVCs in samples of Hongqujiu aged for six distinct years. Based on metabolic differences, the samples were categorized into two groups: the low-year group (5-year, 6-year) and the high-year group (8-year, 10-year, 15-year, 20-year). Nineteen VOCs (e.g., 4-amino-butyric acid and diethanolamine) and thirty NVCs (e.g., palmitoylethanolamide and erinacine D) were identified as key differential metabolites distinguishing the low-year group from the high-year group. The higher-year group is enriched with a variety of substances with different flavors or biological activities, such as sugar derivatives, amino acids and their complexes, organic acids and their intermediate metabolites, steroids and terpenoid compounds, lipids and their derivatives, nitrogen-containing heterocycles, and aromatic compounds. The accumulation of these substances not only shapes the unique and rich flavor characteristics of aged red rice wine (such as the caramel aroma and umami peptide flavor), but also endows red rice wine with potential health benefits due to the physiological regulatory functions of some active ingredients. This study contributes to a deeper understanding of the composition and dynamic variations in metabolites in Hongqujiu, offering a scientific foundation for identifying aged Hongqujiu and conducting further research to enhance its quality. Full article

Background: The accumulation of secondary metabolites in medicinal plants is often influenced by a variety of factors, and rhizosphere microorganisms typically engage in complex interactions with their host plants. Crepis napifera (Franch.) Babc., a regionally significant medicinal plant, contains a diverse array of terpenoids and demonstrates substantial potential for resource development and utilization. Methods: Transcriptome sequencing, metabolomic profiling, and 16S rRNA gene amplicon sequencing were employed to assess the transcriptional expression patterns, metabolic variations, and rhizosphere microbial community composition of C. napifera (Franch.) Babc. roots distributed across various regions. Results: A total of 3679, 8615, and 11,333 differentially expressed genes (DEGs) were identified in the pairwise comparisons between H1 vs. H2, H2 vs. H3, and H1 vs. H3, respectively. Notably, 497 DEGs were consistently detected across all three comparisons. Additionally, Weighted Gene Co-expression Network Analysis (WGCNA) revealed that the expression levels of genes within the turquoise and yellow modules exhibited a significant positive correlation with elevation. In total, 462 differentially expressed metabolites (DEMs) were identified across the same comparisons. Among these compounds, terpenoids, phenolic acids, amino acids and their derivatives, lipids, and alkaloids accounted for 62.98% of the total differential metabolite content. The accumulation patterns of DEMs varied significantly across different regions in the roots of C. napifera (Franch.) Babc. under the three altitude conditions. In response to environmental conditions and the survival strategy of C. napifera (Franch.) Babc. in alpine areas, an investigation into the rhizosphere microbial community was conducted. Four key microbial genera were identified as being correlated with terpenoid biosynthesis and plant nutritional metabolism. Specifically, Pedosphaera, Acidothermus, and Nevskia exhibited terpene biosynthesis capabilities. Additionally, Herbaspirillum, a common microorganism involved in plant nitrogen fixation, respiration, carbon metabolism, and cell wall metabolism, was also enriched in the rhizosphere of C. napifera (Franch.) Babc. These findings suggested that C. napifera (Franch.) Babc. might recruit these microorganisms to enhance its resistance to environmental stress in alpine areas. Conclusions: The accumulation of terpene in C. napifera (Franch.) Babc. across different regions was influenced by transcriptional changes. The rhizosphere microbial communities also changed during this process, showing a recruitment effect that enhances plant growth and offers potential value. Full article

The flavour of foxtail millet (Setaria italica (L.) P. Beauv.) is an important indicator for evaluating the quality of the millet. The volatile components in steamed millet porridge samples were analysed using electronic nose (E-Nose) and gas chromatography–ion mobility spectrometry (GC-IMS) techniques, and characteristic volatile fingerprints were constructed to clarify the differences in the main flavour substances in different foxtail millet varieties (two hybrids and two conventional foxtail millets). After sensory evaluation by judges, Jingu 21 (JG) scored significantly higher than the other varieties, and the others were, in order, Jinmiao K1 (JM), Changzagu 466 (CZ) and Zhangzagu 3 (ZZ). E-Nose analysis showed differences in sulphides and terpenoids, nitrogen oxides, organosulphides and aromatic compounds in different varieties of millet porridge. A total of 59 volatile components were determined by GC-IMS in the four varieties of millet porridge, including 23 aldehydes, 17 alcohols, 9 ketones, 4 esters, 2 acids, 3 furans and 1 pyrazine. Comparative analyses of the volatile components in JG, JM, ZZ and CZ revealed that the contents of octanal, nonanal and 3-methyl-2-butenal were higher in JG; the contents of trans-2-butenal, 2-methyl-1-propanol, trans-2-heptenal and trans-2-pentenal were higher in JM; and the contents of 2-octanone, hexanol, 1-octen-3-ol, 2-pentanone and butyraldehyde were higher in ZZ. The contents of 2-butanol, propionic acid and acetic acid were higher in CZ. A prediction model with good stability was established by orthogonal partial least squares discriminant analysis (OPLS-DA), and 25 potential characteristic markers (VIP > 1) were screened out from 59 volatile organic compounds (VOCs). These volatile components can be used to distinguish the different varieties of millet porridge samples. Moreover, we found conventional foxtail millet contained more aldehydes than the hybridised foxtail millet; especially decanal, 1-nonanal-D, heptanal-D, 1-octanal-M, 1-octanal-D and 1-nonanal-M were significantly higher in JG than in the other varieties. These results indicate that the E-Nose combined with GC-IMS can be used to characterise the flavour volatiles of different foxtail millet, and the results of this study may provide some information for future understanding of the aroma characteristics of foxtail millet and the genetic improvement of hybrid grains. Full article

Better quality and odor of silage and normal microbial fermentation metabolism are mostly dependent on an appropriate moisture content. The purpose of this study was to determine the effects of different moisture content gradients (50, 60, 70, and 80%) on the bacterial community, odor, and quality of alfalfa silage at 60 days by using gas chromatography–mass spectrometry (GC–MS) and electronic nose, with six replicates per group. The results showed that there were significant differences in odor response intensity among all groups, among which the 80% group had the strongest reaction to terpenoids, sulfides, and nitrogen oxides. Similarly, the different volatile organic compounds (VOCs) were mainly terpenoids, alcohols, and ketones, such as pine, camphor, and menthol (e.g., carlin and levomenthol). The dominant bacterium was Enterococcus with higher fiber, pH, and ammonia nitrogen (NH₃-N) content but poorer quality and odor (p < 0.05). The differential VOCs in the 60% group were mainly heterocyclics, esters, and phenols with fruity, floral, and sweet odors such as 2-butylthiophene and acorone. Pediococcus and Lactiplantibacillus were the dominant bacteria, with higher crude protein (CP), water-soluble carbohydrates (WSC), and lactic acid (LA) contents, as well as better quality and odor (p < 0.05). The biosynthesis of terpenoids and steroids, biosynthesis of secondary metabolites, and biosynthesis of phenylpropanoids were the main metabolic pathways of differential VOCs. In conclusion, regulating moisture content can alter bacterial community and metabolites, which will encourage fermentation and enhance alfalfa silage quality and odor. Full article

Intercropping is a promising strategy for sustainable medicinal plant cultivation, but its impact on plant–microbe interactions remains poorly understood. This study investigated the influence that intercropping giant lily (Cardiocrinum giganteum) with bamboo (BG), Chinese fir (FG), and mixed forests (MG) had on the giant lily metabolome and microbiome compared to a monoculture control (GG). Metabolomic analysis revealed that BG significantly increased the accumulation of terpenoids (e.g., yucalexin B22, 19.39-fold), alkaloids (e.g., anabasine, 2.97-fold), and steroids (e.g., O-acetyl-lariciresinol, 4.49-fold), while MG induced the production of stress-related metabolites (e.g., aflatoxin G2, 128.62-fold), and FG enhanced nitrogen metabolism (e.g., putrescine, 2.47-fold). Intercropping altered the rhizosphere and endophytic microbial communities, with BG enriching beneficial bacteria (e.g., Acidobacteria and Alphaproteobacteria) and FG promoting symbiotic fungi (e.g., Serendipita and Xylariales). Network analysis revealed strong correlations between specific microbial taxa (e.g., Bacillus and Ceratobasidiaceae) and key metabolites (e.g., norpandamarilactonine A, methylgingerol), indicating their potential roles in shaping the metabolic profiles of giant lily. These findings highlight the complex interplay between intercropping systems, microbial communities, and medicinal plant metabolism and provide a basis for developing targeted cultivation strategies to enhance the production of bioactive compounds in giant lily and other medicinal plants. Full article

Chemical traits (primary and secondary metabolites) are important features of plants. An increasing number of studies have focused on the ecological significance of secondary metabolites in plant parts, especially in pollen. Ericaceae species exhibit significant morphological variations and diverse colors, are widely distributed throughout China and are popular ornamental garden plants. The chemical trait of pollen in Ericaceae species and their potential ecological significance remain unclear. We selected a total of nine Ericaceae species from three nature reserves in southwestern China, which were the predominant flowering Ericaceae plants for each site, and measured their floral characteristics, nectar volume and sugar concentration. We determined the types of pollinators of these species based on a literature review and used UPLC-QTOF-MS to analyze the types and relative contents of primary metabolites (amino acids and fatty acids) and secondary metabolites (terpenoids, phenolics and nitrogenous compounds) in the pollen and other tissues, including the stems, leaves, petals and nectar. The results showed that each species exhibited unique floral characteristics. Enkianthus ruber, Pieris formosa, Rhododendron agastum, R. irroratum, R. virgatum and R. rubiginosum were pollinated by bees, and R. delavayi, R. decorum and R. excellens were pollinated by diverse animals (bees, birds and Lepidoptera). The pollen of these Ericaceae species was rich in phenolics and terpenoids, especially flavonoids. Grayanotoxin, andromedotoxin and asebotin (toxic diterpene compounds) were also detected in the pollen of some of the Ericaceae species in our study, and their response value was low. The relative contents and diversity of secondary metabolites in the pollen were higher than those in the nectar but lower than those in the leaves, petals and stems. The five chemical compounds with the highest content (four flavonoids, one triterpene) in the pollen were also detected in the stems, leaves and petals, and the response value of most of these chemicals in pollen was not significantly correlated with that in other tissues. Rhododendron species has a closer relationship with chemical traits in pollen compared with Enkianthus and Pieris species. The response value of total secondary metabolites in the pollen of species pollinated only by bees was higher than that of species pollinated by diverse animals. Our research indicates that the pollen of ericaceous species contains a wide array of metabolites, establishing a foundation for advancing the nutritional potential of the pollen of horticultural ericaceous species and deepening our understanding of its chemical and ecological significance. Full article

Background: Plants constantly produce primary and secondary metabolites, and a significant fraction of these are volatile organic compounds (VOCs). Factors including the life stage of the plant, temperature, environment, and stress influence the abundance and types of VOCs emitted. The analysis of VOCs released by plants during different stages or with different conditions provides insight into plant metabolism and stress responses. Collecting the VOC profiles of plants in vivo makes it possible to obtain a representative sample of the entire plant volatilome under controlled conditions with minimal invasiveness. In addition, in vivo sampling can also be used to compare the impacts of different environmental conditions or stressors on plants, i.e., the presence/absence of a pest or amount of nitrogen in soil. Methods: In this study, an in vivo plant sampling technique is introduced and validated using active sampling and thermal desorption (TD) tubes with comprehensive two-dimensional gas chromatography coupled to a time-of-flight mass spectrometer (TD-GC×GC-TOFMS). The purpose of this work is to highlight a novel technique to analyze headspace secondary plant metabolites with a minimal invasiveness. Results: It was concluded that in vivo active sampling onto TD tubes provides a wider global coverage of compounds and larger peak areas when compared to extraction by solid-phase microextraction (SPME). Additionally, the Horwitz ratio of active sampling onto TD tubes was 0.893, demonstrating this technique to be a reliable and reproducible method. Lastly, a variety of plants were sampled to assess the versatility of this technique across various plant species with different sizes and volatile profiles. Hundreds of compounds were measured with this analysis, including terpenes, aldehydes, ketones, terpenoids, and alcohols. Conclusions: This novel in vivo active sampling method provides an additional technique for extracting and analyzing volatile secondary plant metabolites. Full article

Fusarium species are commonly found in soil, water, plants, and animals. A variety of secondary metabolites with multiple biological activities have been recently isolated from Fusarium species, making Fusarium fungi a treasure trove of bioactive compounds. This mini-review comprehensively highlights the newly isolated secondary metabolites produced by Fusarium species and their various biological activities reported from 2019 to October 2024. About 276 novel metabolites were revealed from at least 21 Fusarium species in this period. The main metabolites were nitrogen-containing compounds, polyketides, terpenoids, steroids, and phenolics. The Fusarium species mostly belonged to plant endophytic, plant pathogenic, soil-derived, and marine-derived fungi. The metabolites mainly displayed antibacterial, antifungal, phytotoxic, antimalarial, anti-inflammatory, and cytotoxic activities, suggesting their medicinal and agricultural applications. This mini-review aims to increase the diversity of Fusarium metabolites and their biological activities in order to accelerate their development and applications. Full article