Search Results (1,879)

Mycotoxigenic fungi contaminate cereals, nuts, fruits, and other food commodities, threatening human and animal health. This review focuses on Aspergillus flavus, Fusarium verticillioides, and Alternaria alternata as representative mycotoxigenic fungi because of their importance as food contaminants and their production of major food-relevant mycotoxins. Some methods detect fungal presence or toxigenic potential, whereas others directly quantify toxins. Fungal identification or detection of biosynthetic genes indicates presence or toxin-producing potential, respectively, but neither replaces direct mycotoxin measurement. The diversity of targets, toxins, and food matrices remains a challenge for accurate and practical analysis. Particular attention is given to immunodiagnostic approaches, including enzyme-linked immunosorbent assays (ELISAs), as well as complementary formats such as lateral flow immunoassays (LFIAs), and immunosensors, for laboratory and on-site food safety monitoring. The advantages and limitations of these approaches, with emphasis on sensitivity, specificity, matrix effects, and sample preparation, are discussed. Future aspects will focus on integrated, matrix-validated workflows combining robust sample preparation, multiplex recognition, portable readout, and appropriate quality controls to enable faster and more reliable monitoring of fungal contamination and mycotoxins throughout the food and feed chain. Full article

Melatonin (MT) is an important bioactive functional component of milk, where its content and biosynthetic mechanism are of considerable relevance to the quality regulation of dairy buffalo milk. This study aimed to investigate the variation patterns and biosynthetic mechanisms of melatonin in milk from dairy buffaloes. A total of 125 buffalo milk samples were collected, and MT content was determined using liquid chromatography–tandem mass spectrometry (LC–MS/MS). MT secretion patterns were evaluated according to breed, lactation, parity, and milking time (light exposure). In addition, whole-genome sequencing (WGS) data were used to screen for single-nucleotide polymorphisms (SNPs), which are significantly associated with melatonin biosynthetic enzyme genes. The results showed that breed, milking time, and lactation were the major factors affecting MT content in buffalo milk. Based on the WGS data, two SNPs significantly associated with MT secretion and synthesis were identified within the aralkylamine N-acetyltransferase (AANAT) region, among which the GG genotype at 3-8019407 and the CC genotype at 3-8019446 were associated with higher MT content. The MT content for both wild-type homozygotes was 59.54 pg/mL, which was higher than that of heterozygotes (39.12 pg/mL) (p < 0.05). With the exception of SNP2 and SNP8, all other SNPs were in Hardy–Weinberg equilibrium. These findings will serve as a reference for the subsequent selection and identification of breeding materials for high MT dairy buffalo, as well as for the development of high MT buffalo milk products. Full article

Cold stress severely limits the productivity of maize, especially in Northeast China. Hydroxymethylbutenyl diphosphate synthase (HDS) is a key enzyme in the methylerythritol phosphate (MEP) pathway, which is responsible for the generation of precursors for carotenoid biosynthesis, thereby playing a central role in facilitating the cellular response to stress. In the present study, virus-induced gene silencing (VIGS)-mediated ZmHDS1 silencing on the B73 background led to enhanced cold stress sensitivity, as evidenced by growth retardation, leaf shriveling, disrupted Kranz anatomy, elevated reactive oxygen species (ROS) accumulation, impaired antioxidant enzyme activity, increased membrane lipid peroxidation, and reduced photosynthetic performance. Hormonal profiling revealed that ZmHDS1 silencing decreased the content of indole-3-acetic acid (IAA), gibberellin (GA₄), and abscisic acid (ABA) and disrupted ABA signaling. Furthermore, ZmHDS1 silencing reduced the chlorophyll content, Rubisco activity, and ZmRCA (Rubisco activase) expression and caused a more severe reduction in carotenoid levels and the transcriptional suppression of the entire carotenoid biosynthetic gene network. Collectively, ZmHDS1 acts as a key component of the MEP pathway that contributes to maize cold tolerance by coordinating antioxidant defense, phytohormone homeostasis, photosynthetic maintenance, and carotenoid metabolism. These findings highlight the importance of the MEP pathway as a whole in cold adaptation. Disruption of ZmHDS1 impairs these interconnected protective mechanisms, rendering maize highly susceptible to cold-induced damage. Full article

Long-chain polyunsaturated fatty acids (LC-PUFAs) are essential to the nutrition, metabolism, and physiological performance of aquatic animals. This hybrid review combines bibliometric analysis with focused thematic synthesis to examine three decades (1991–2025) of research on LC-PUFA biosynthesis in aquatic species. Bibliometric trends reveal rising publication output and an expanding research focus on biosynthetic pathways, regulatory mechanisms, and molecular control of LC-PUFA production, with emerging emphasis on metabolomics, environmental regulation, microalgae-derived ω-3 sources, and gene-editing technologies. Thematic analysis reveals that LC-PUFA dynamics are governed by interactions among primary production, trophic transfer, endogenous biosynthetic capacity, and environmental conditions. Marine primary producers serve as major sources of EPA and DHA, whereas freshwater and terrestrial systems often exhibit greater ALA availability and higher n-6/n-3 ratios, influencing LC-PUFA transfer efficiency and consumer adaptation. The review further highlights that aquatic animals have evolved diverse endogenous biosynthetic strategies, including lineage-specific modifications of desaturase and elongase pathways, enabling adaptation to contrasting nutritional environments. LC-PUFA transport across aquatic–terrestrial boundaries through organisms such as emergent insects and amphibians represents an important pathway for transferring essential fatty acids to terrestrial food webs. Furthermore, variation in n-3 LC-PUFA availability contributes to habitat selection and evolutionary diversification, with freshwater environments promoting enhanced biosynthetic capacity through mechanisms such as Fads2 gene duplication. Future directions include structural characterization of biosynthetic enzymes via cryo-electron microscopy and AI-assisted modeling, multi-omics and genome-editing strategies for genetic improvement, and sustainable production approaches including microalgae- and insect-based feeds and integrated multitrophic aquaculture. Full article

Streptomyces sp. HR58, isolated from the hop rhizosphere, exhibits antifungal activity against a variety of fungal phytopathogens affecting many crops. HR58 was characterized using phenotypic and genomic approaches. Growth tolerance and enzymatic activities were assessed, and whole-genome sequencing enabled the prediction of biosynthetic gene clusters. The strain HR58 displayed morphological and biochemical traits characteristic of the genus Streptomyces, growing from pH 5 to pH 12 and salt tolerance up to 5% NaCl. Genome analysis revealed a size of 8,270,372 bp with a GC content of 71.76% and the presence of gene clusters associated with antifungal activity. Although ANI analysis showed 96.6% identity with Streptomyces anulatus ATCC 11523, the dDDH value of 66.5% fell below the species delineation threshold of 70%, indicating that HR58 cannot be confidently assigned to any currently described Streptomyces species. A biosynthetic gene cluster encoding the antifungal compound cycloheximide was identified in its genome, and cycloheximide production was assessed in liquid cultures. Silver nanoparticle (AgNP) biosynthesis by strain HR58 was also confirmed, and its antimicrobial activity was evaluated. The ability of strain HR58 to biosynthesize antifungal nanoparticles further enhances its potential applications in sustainable agriculture, offering a promising alternative for the development of eco-friendly plant disease control strategies. Full article

Efficient irrigation is pivotal for viticulture in arid regions; however, solutions that simultaneously stabilize vine water status, sustain yield, and preserve fruit quality remain limited. We evaluated a microfiber-based wicking infiltration irrigation system—applied at the surface (W1) and shallow-buried at 10 cm (W2)—against drip (DI) and furrow (FI) irrigation in a two-year field trial with table grapes in northwest China. Additional wicking infiltration irrigation quota treatments (W1-2/3, W1-1/3) were also tested. The experiment combined continuous root-zone moisture and predawn leaf water potential (Ψpd) measurements with assessments of growth, berry traits, anthocyanins, and expression of related genes, synthesizing outcomes using an AHP–entropy multi-criteria framework. Wicking infiltration irrigation reduced wet–dry fluctuations, increased minimum soil moisture, and mitigated excursions to low Ψpd relative to DI and FI, indicating a more stable hydraulic environment for vines. W2 and W1-2/3 delivered the highest or near-highest yields (up to 16.5 kg per vine). Relative to DI, W2 increased IWUE by 57.9% in 2018 and 9.3% in 2019, whereas W1-2/3 increased IWUE by 155.1% and 66.0%, respectively. The AHP–EW evaluation identified W2 as the best overall integrated treatment, with the highest cumulative score across the two years (1.22), while W1-2/3 provided the strongest yield–IWUE balance under reduced irrigation. Anthocyanin accumulation and the expression of related biosynthetic genes showed year- and treatment-dependent responses; moderate water deficit was associated with enhanced anthocyanin-related responses at some developmental stages, but this effect was not consistent across seasons. These results indicate that wicking infiltration irrigation can improve grape production and irrigation efficiency under arid conditions, although its effects on berry secondary metabolism depend on seasonal and irrigation conditions. Full article

Catechins are the major bioactive polyphenolic compounds in tea (Camellia sinensis) and key determinants of its astringency, flavor quality, and health value. Although DNA methylation has been associated with catechin biosynthesis in tea, the roles of chromomethylase (CMT) genes in regulating catechin accumulation remain unclear. In this study, we characterized the CMT gene family in C. sinensis and identified four members: CsCMT1, CsCMT2, CsCMT3a, and CsCMT3b. All CsCMT genes were preferentially expressed in buds and young leaves, the tissues harvested for tea production, and CsCMT2 showed the most pronounced cultivar-dependent expression under Colletotrichum gloeosporioides infection. Transient overexpression of CsCMT2 in tea leaves decreased the contents of all six measured catechins (EGCG, GCG, EGC, GC, EC, and C), with EGCG showing the greatest reduction. It also downregulated seven catechin biosynthetic genes, namely CsPAL, CsC4H, CsCHI, CsF3′5′H, CsDFR, CsANR, and CsSCPL1A. Conversely, virus-induced gene silencing of CsCMT2 increased total catechin content and upregulated these genes. Caffeine content was not significantly affected by either manipulation, indicating a relatively specific effect on catechin metabolism. These results suggest that CsCMT2 negatively affects catechin accumulation associated with transcriptional changes in pathway genes and is a potential target for modulating catechin composition and flavor quality in tea germplasm improvement. Full article

Eragrostis curvula (Schrad.) Nees is a C4 perennial grass used as forage in semiarid regions, and its quality varies among cultivars. Given the limited variation in total lignin content among genotypes, cell wall phenolic composition may be a more relevant source of variation. This study characterized the cell wall phenolic profile and analyzed the lignin biosynthetic genes EcCSE-I, EcCSE-II, and EcF5H in three cultivars: the heptaploid Don Pablo and the tetraploids Morpa and Tanganyika. Phenolic compounds released by alkaline nitrobenzene oxidation and alkaline hydrolysis were quantified by HPLC, and transcript levels were measured by qPCR. Don Pablo showed the highest yield of guaiacyl-type oxidation products and the lowest S:G ratio, whereas Morpa showed the lowest guaiacyl and ferulic acid values. The cultivar Tanganyika accumulated the most p-coumaric acid and displayed the highest EcF5H expression. Sequencing of EcCSE-I, EcCSE-II and EcF5H orthologs in six accessions spanning three ploidy levels resolved EcCSE-I into two divergent sequence lineages that do not follow ploidy level, differing at up to 19 of 341 residues while retaining all residues required for esterase activity. The observed concordance between transcript abundance and cell wall phenolic composition identifies EcCSE-I and EcF5H as preliminary candidate genes in this species. Full article

Proeulia auraria (Lepidoptera: Tortricidae) is a native Chilean moth and a significant pest of several fruit crops. Its sexual communication relies on pheromones, of which (E)-11-tetradecenyl acetate (E11-14:OAc) is the major component, but the mechanisms regulating its production and biosynthetic pathways are poorly understood. We studied the effect of pheromone-biosynthesis-activating neuropeptide (PBAN) on pheromone production and its biosynthesis through isotopic labeling using deuterated fatty acids, which were topically applied to the pheromone gland. Gas chromatography–mass spectrometry (GC-MS) analysis was then performed. PBAN application increased E11-14:OAc by up to eight times. In labeling experiments with [16,16,16-²H₃]hexadecanoic acid (D₃-16:acid), the mass spectrum of E11-14:OAc showed a shifted ion at m/z 197 and a natural ion at m/z 194. These results indicated the incorporation of three deuteriums into the terminal methyl group and that chain shortening from palmitic acid to the 14-carbon skeleton occurs through β-oxidation from the carboxyl end. Deuterium incorporation was also detected after D₃-18:acid and D₃-14:acid application. The findings provide the first direct evidence regarding the precursors and direction of chain shortening in the pheromone biosynthesis of P. auraria. The information contributes to our understanding of its chemical communication and could lay the foundation for the development of pheromone-based control tools. Full article

Glycolic acid (GA) is an important platform chemical with applications in biodegradable polymers, cosmetics, and pharmaceutical synthesis; however, traditional petrochemical routes raise environmental concerns, and current microbial production platforms remain constrained by acid toxicity. In this study, systematic metabolic engineering combined with fermentation optimization was implemented to construct an efficient GA biosynthetic pathway in the acid-tolerant non-conventional yeast Issatchenkia orientalis. To redirect the metabolic flux of the glyoxylate cycle, the Arabidopsis thaliana glyoxylate reductase (AtGLYR), with a catalytic efficiency approximately 74-fold higher than that of the native yeast enzyme, was heterologously expressed, coupled with the overexpression of endogenous isocitrate lyase (ICL) and the knockout of the competing malate synthase (MLS) gene. Furthermore, a heterologous xylose assimilation pathway was integrated into the engineered strain to rescue the growth deficiency caused by mls deletion. Subsequent fermentation optimization via an ethanol–xylose co-feeding strategy and calcium carbonate supplementation effectively further improved GA accumulation. Ultimately, the optimized engineered strain yielded a maximum GA titer of 712.42 mg/L in shake-flask fermentation. This work validates the potential of I. orientalis as a robust chassis microbe for sustainable GA biosynthesis and broadens the product portfolio of metabolic engineering applications for this yeast strain. Full article

Lactic acid bacteria (LAB) are promising microbial candidates for sustainable agriculture, but their combined plant-growth-promoting and biocontrol potential remains underexplored. In this study, 32 previously isolated LAB strains were evaluated for in vitro antifungal activity against four phytopathogens, plant-growth-promoting traits, antimicrobial biosynthetic markers, safety attributes, and in vivo effects on Brassica napus. Antagonistic activity was strong but strain-dependent, with the greatest inhibition observed against Pythium heterothallicum and several isolates showing broad-spectrum activity against Fusarium equiseti, Geotrichum citri-aurantii, and Botrytis cinerea. Functional screening revealed complementary traits, including phosphate solubilization, acid phosphatase and cellulase activities, and the production of ammonia, siderophores, and hydrogen cyanide. PCR screening detected putative markers associated with iturin and subtilosin biosynthesis in a subset of strains. No hemolytic or DNase activity was detected, and no broadly concerning antibiotic resistance profiles were observed. No strain consistently outperformed all others across inoculum densities, highlighting a nonlinear dose–response relationship and the need for strain-specific inoculum optimization. Overall, several LAB strains emerged as promising dual-function bioinoculant candidates. Full article

Umbelliferone, a key precursor for the biosynthesis of high-value furanocoumarin derivatives, is produced via the shikimate pathway. The oleaginous yeast Yarrowia lipolytica possesses an inherently robust shikimate pathway; however, de novo biosynthesis of umbelliferone in this microbial chassis has not been realized to date. Low intracellular pools of p-coumaric acid and suboptimal catalytic activity of downstream hydroxylation and cyclization enzymes represent the major bottlenecks limiting efficient umbelliferone production. In this study, we systematically screened five PAL/TAL variants, three 4CL isoforms, and two C2′H enzymes derived from diverse plant and microbial sources. The bifunctional enzyme RtPAL-TAL exhibited the highest productivity of p-coumaric acid, while the combination of At4CL3 and RgC2′H achieved the maximum umbelliferone accumulation. Expression of feedback-insensitive shikimate pathway mutant enzymes effectively relieved intrinsic pathway feedback inhibition, resulting in a 10.2-fold improvement in p-coumaric acid titer. All synthetic biosynthetic gene cassettes were stably integrated into the Y. lipolytica genome to generate the engineered strain YL-PU, which yielded 3.29 mg/L umbelliferone in shake-flask cultures. Further fed-batch fermentation in a 5 L bioreactor increased the umbelliferone titer to 125.52 mg/L at 84 h of cultivation. This work establishes the first de novo umbelliferone biosynthesis pathway in Y. lipolytica and identifies that C2′H represents a major candidate bottleneck under the tested configuration, in agreement with earlier findings. These findings provide a robust foundation for further metabolic engineering of the Y. lipolytica chassis to enable high-titer production of coumarins and other phenylpropanoid natural products. Full article

Drought is a major abiotic constraint on plant productivity, and plant growth-promoting rhizobacteria (PGPR) provide a sustainable strategy for improving crop drought tolerance. The rhizosphere of the dominant Mu Us Desert plant Artemisia ordosica may harbor drought-adapted microorganisms, but their functions remain insufficiently characterized. In this study, drought-tolerant rhizobacteria isolated from the A. ordosica rhizosphere were screened for growth-promoting effects on lettuce (Lactuca sativa L.) under controlled pot conditions. The dominant strain FSO7, identified as Pseudomonas fluorescens, exhibited the strongest effects. Under drought stress, FSO7 inoculation significantly increased plant height, stem width, fresh weight, and dry weight by 26.62%, 111.29%, 310.19%, and 44.02%, respectively, relative to uninoculated controls. Integrated transcriptomic and untargeted metabolomic analyses showed that FSO7 inoculation was associated with marked changes in lettuce carbon metabolism under drought, involving genes and metabolites related to starch and sucrose metabolism, glycolysis, and the TCA cycle, concurrently with up-regulation of genes in the flavonoid biosynthetic pathway. These findings suggest that P. fluorescens FSO7 may alleviate drought-induced growth inhibition in lettuce through coordinated modulation of carbon metabolism and flavonoid-mediated antioxidant metabolism. This strain represents a promising microbial resource for developing bioinoculants for water-limited agriculture. Full article

Background: Antimicrobial resistance in foodborne pathogens and demand for clean-label foods highlight the need for natural antimicrobial preservatives. Paenibacillin, an antimicrobial peptide produced by Paenibacillus polymyxa OSY-DF, has potential as a natural preservative, but low productivity limits its application. Paenibacillin is encoded by an 11-gene biosynthetic gene cluster (BGC) containing seven biosynthetic genes and a putative accessory gene regulator (Agr)-like quorum sensing (QS) locus (agrABCD). Understanding the association between QS systems and paenibacillin biosynthesis may provide insights into factors influencing its production. Methods: The Agr-like QS system was assessed through a time-course transcriptional analysis of the paenibacillin BGC and antimicrobial bioassays. AI-2 activity was detected using Vibrio harveyi, and its potential regulatory role was assessed by inhibiting AI-2 signaling with D-ribose. Results: Transcription of agrABCD increased after 4 h, reaching 18.59- to 202.61-fold upregulation at 24 h relative to 0 h. In contrast, limited transcription of the seven biosynthetic genes was detected during the initial 8 h, followed by 19.64- to 136.12-fold upregulation at 24 h. Anti-Listeria activity was first detected at 12 h and increased through 24 h. These transcriptional and phenotypic patterns suggest a potential association between the Agr-like QS system and paenibacillin BGC expression. AI-2 was detected in OSY-DF culture supernatants; however, reducing AI-2 signals did not reduce paenibacillin activity. Conclusions: Paenibacillin production is growth phase-dependent and temporally associated with Agr-like gene transcription, whereas AI-2 does not appear to regulate its biosynthesis. Functional validation through targeted agr disruption is required to define the direct regulatory role of the Agr-like QS system. Full article

Pigmented rice is valued for its abundant natural bioactive compounds and potential health-promoting properties. In this study, the black rice cultivar Huamoxiang No. 5 (HMX) was used to develop three genetically similar rice lines with distinct pericarp pigmentation. Among them, BRHMX (a dual-pigmented rice accumulating both anthocyanins and proanthocyanidins) and RHMX (a red rice accumulating proanthocyanidins) were generated through hybridization, successive backcrossing, and marker-assisted selection, whereas the white rice line WHMX was derived from a spaceflight-induced mutant of HMX. Comparative analyses revealed that differences in pericarp pigmentation had negligible effects on grain morphology and major nutritional components, including starch, protein, and amino acids. Compared with HMX, BRHMX maintained more than 80% of the anthocyanin content of HMX, while its proanthocyanidin content was 103% higher than that of RHMX. Furthermore, BRHMX exhibited the highest total phenolic content and the highest levels of 31 soluble phenolic acids, together with the strongest chemical antioxidant capacity, as determined by ABTS and FRAP assays. Untargeted metabolomic profiling showed that flavonoids and soluble phenolic acids were the major metabolite classes associated with pericarp color divergence. Integrated metabolomic and transcriptomic analyses further suggested a potential reallocation of metabolic flux between anthocyanin and proanthocyanidin biosynthetic pathways during early pericarp development. Cooking generally reduced the contents of anthocyanins, proanthocyanidins, and total phenolics, as well as chemical antioxidant capacity, although the magnitude of these changes varied among the four lines. Collectively, these findings demonstrate that the newly developed dual-pigmented rice line combines characteristics associated with conventional black and red rice, providing a valuable genetic resource for whole-grain rice product development. Full article