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Journal of Agricultural and Food Chemistry

American Chemical Society (ACS)

Preprints posted in the last 90 days, ranked by how well they match Journal of Agricultural and Food Chemistry's content profile, based on 15 papers previously published here. The average preprint has a 0.02% match score for this journal, so anything above that is already an above-average fit.

1
Seasonal dynamics of microbial communities mediate aroma and flavour formation during palm sap fermentation

Sumerta, I. N.; Howell, K.

2026-07-13 microbiology 10.64898/2026.07.12.737599 medRxiv
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In many tropical countries, fermentation of palm sap into palm wine is an important fermented beverage contributing to local economies, tradition, and culture. Traditionally made in villages and families, palm sap is not inoculated with starter cultures and fermentation commences spontaneously. It is therefore possible that fermentation is influenced by multiple ecological factors, which affect microbial dynamics and thus flavour outcomes. Here, we studied microbial communities during fermentation of palm sap from three different palm tree species (palmyra, coconut, and sugar palm) on the island of Bali, Indonesia in both the wet and dry seasons. Our results suggest that season of collection has a strong influence on microbial dynamics and succession, and these changes positively correlate to metabolite concentration. The change of the season from the dry to wet season led to the loss of microbial diversity with lower richness in the dry season. The dominance of Saccharomyces cerevisiae was not affected by season and fermentation time and was dominant in all samples. Potential spoilage species, such as Candida tropicalis were negatively correlated to ester production and more abundant in the dry season. As microbial species varied in incidence and thus biochemical activity, the chemical groups of esters from their metabolism related to the change of season and fermentation time, while volatile compounds and small molecules were highly discriminated by season in the resultant wines. Ethyl octanoate was consistently different across all variables through comparison by three-way ANOVA and is proposed as a biomarker of seasonal variation in palm sap fermentation. These findings improve our understanding of microbial dynamics in palm sap fermentation, revealing flavour differentiation within season and suggests that strategies for microbial management, product development and quality assurance will elevate this traditional product into the future.

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Species and Accession Diversity of Secondary Metabolites and Antioxidant Activity in Legume Sprouts

An, G.; Kwon, H.; Ha, J.

2026-08-03 plant biology 10.64898/2026.07.31.741982 medRxiv
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Legume sprouts contain diverse bioactive phytochemicals, yet species- and accession-level comparisons of antioxidant properties and secondary metabolites remain limited. Antioxidant capacity, total phenolic content (TPC), total flavonoid content (TFC), and 19 secondary metabolites were evaluated in sprouts of soybean (Glycine max (L.) Merr.), mungbean (Vigna radiata (L.) R. Wilczek), cowpea (Vigna unguiculata (L.) Walp.), and peanut (Arachis hypogaea L.), using ten accessions per species under standardized conditions. Mungbean and cowpea sprouts showed significantly higher antioxidant activity, TPC, and TFC than soybean and peanut; across accessions, ABTS and DPPH activities ranged from 13.67 to 49.33% and 7.91 to 55.16%, and TPC and TFC from 3.91 to 13.81 mg GAE/g and 0.05 to 1.04 mg QE/g, respectively. Metabolite profiling revealed species-specific patterns, including isoflavones in soybean, rutin in mungbean, coumestrol in cowpea and resveratrol in peanut. Both antioxidant and phytochemical profiles varied with species and accession, so both can be selected to obtain sprouts with targeted properties.

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Differential Regulation of Branched-Chain Amino Acids During Early Germination of Mungbean (Vigna radiata L.)

Kim, C.; Kwon, H.; Lim, S. D.; Jo, Y.-J.; Ha, J.

2026-08-03 plant biology 10.64898/2026.07.31.741962 medRxiv
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Branched-chain amino acids (BCAAs) are essential amino acids involved in protein synthesis and energy metabolism. Because animals cannot synthesize BCAA de novo, plant-derived BCAAs are important to human nutrition. Although mungbean sprouts are widely consumed as functional plant-based food materials, changes in individual BCAA accumulation and their transcriptional regulation during mungbean germination remain poorly understood. In this study, amino acid contents and transcriptomic profiles were analyzed at three germination stages, 8H, 24H, and 72H. Total BCAA content increased during germination, whereas individual BCAAs exhibited distinct temporal accumulation patterns. Isoleucine and valine increased until 72H, while leucine increased during early germination and decreased after 24H. Transcriptome analysis revealed time-dependent expression changes in BCAA biosynthesis and degradation genes associated with the leucine decrease after 24H. These findings suggest that 24H represents an important transition point for BCAA accumulation and compositional change during mungbean germination. This study provides molecular evidence for the regulation of BCAA metabolism during mungbean germination and supports the potential use of germinated mungbean as a plant-based amino acid resource.

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Alternaria solani infection reprograms potato leaf metabolism and highlights potential defence and metabolic markers

Singh, P. D.; Nayak, R.; Sharma, S.; Masakapalli, S. K.

2026-08-21 plant biology 10.64898/2026.08.17.745268 medRxiv
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Potato (Solanum tuberosum L.), the worlds fourth most cultivated crop, suffers yield losses of up to 40-50% from early blight caused by the necrotrophic fungal pathogen Alternaria solani. In this study we performed gas chromatography-mass spectrometry (GC-MS)-based untargeted metabolomics to characterize temporal alterations in metabolite composition, metabolic pathway regulation, and discriminatory biomarker metabolites in the susceptible Indian potato variety Kufri Jyoti, analyzing infected leaves, non-infected leaves, and lesion-associated necrotic tissues across four days post-inoculation (DPI).Metabolite annotation identified 58 compounds, including sugars, organic acids, amino acids, and secondary metabolites.. Multivariate analyses resolved distinct, largely non-overlapping metabolic clusters for control, infected leaves (1-4 DPI), and lesion tissue (Bs1-Bs3). A biphasic metabolic response was observed: early infection (1-2 DPI) was characterized by general suppression of primary metabolism, while late infection (3-4 DPI) showed pronounced upregulation of glycolysis, the TCA cycle, GS/GOGAT, and the shikimate pathway. Key discriminatory metabolites included asparagine, oxoproline, GABA, phenylalanine, and aromatic amino acids. Lesion tissues exhibited distinct metabolic fingerprints, with early disruption of amino acid recycling followed by a late rebound of defense-associated metabolites. Notably, defence-associated phenolics were detected exclusively within lesion tissue and were absent from whole-leaf profiles, demonstrating that spatially resolved lesion sampling captures defence chemistry that whole-leaf analysis alone would miss. The identified biomarker metabolites, particularly those linked to the shikimate and GS/GOGAT pathways, represent promising candidates for metabolite-assisted breeding and targeted crop protection strategies against early blight in potato. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=115 SRC="FIGDIR/small/745268v1_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@18131edorg.highwire.dtl.DTLVardef@f4fbe6org.highwire.dtl.DTLVardef@1c5db61org.highwire.dtl.DTLVardef@c5ef6d_HPS_FORMAT_FIGEXP M_FIG C_FIG

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Untargeted metabolic analysis reveals intraspecific and organ-specificchemodiversity in Solanum dulcamara

Mendoza-Servin, J. V.; Moreno-Pedraza, A.; Pires Bueno, P. C.; van Dam, N. M.

2026-07-30 plant biology 10.64898/2026.07.29.741464 medRxiv
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Background and AimsThe genus Solanum including the wild species S. dulcamara, is rich in specialized metabolites such as steroidal glycoalkaloids (SGAs). Yet, much of this chemical diversity remains poorly characterized. This study aims to provide a comprehensive assessment of intra-specific chemodiversity in S. dulcamara. Using a dataset generated from 42 globally distributed accessions, we tested whether metabolic profiles differ among plant organs. We postulated that metabolic richness and abundance vary across accessions. Additionally, we hypothesized that differences in geographic origin or altitude affect SGA chemodiversity. MethodsAn untargeted metabolomic approach was applied to leaf, flower and root samples of 42 S. dulcamara accessions. Plants were grown in the greenhouse, and the extracted metabolites were analyzed using UHPLC-HRMS/MS in positive and negative ionization modes. Data processing and metabolite annotation were performed with a tailored bioinformatics workflow. Multivariate analyses were performed to evaluate chemical variation across organs and accessions. Key ResultsOur analyses revealed both organ and accession-specific metabolic diversity. Principal component analysis and clustering analyses revealed metabolic differentiation between leaves, flowers and roots. Leaves showed the highest metabolite richness and abundance, while roots showed the lowest. Alkaloids, especially SGAs, dominated positive mode profiles in roots, whereas shikimates and phenylpropanoids were prominent in negative mode profiles. Based on the leaf and flower SGAs profiles, four chemotypes were identified. Analyses of flavonoid and cinnamic acid derivatives, however, did not reveal chemotypes. Feature-based molecular network analyses confirmed that metabolite clusters are associated with plant organs, but not with altitude or geographic origin of the accessions. ConclusionsThe intraspecific chemodiversity within S. dulcamara is mainly driven by organ and accession-specific metabolic differences. We identified four SGA leaf and flower chemotypes, suggesting possible functional and ecological roles of this aboveground chemodiversity. These insights may contribute to applied research in plant resistance breeding and crop production.

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Probiotic-Directed Fermentation Reprograms the Metabolic Profile of a Traditional Mongolian Whole-Wheat Diet and Modulates Escherichia coli-Induced Gut Microbiota Dysbiosis

duleng, E.; Ling, Q.; Bao, J.; Gaga, S.; gexi, T.; dien, N.; dan, S.; ruhan, A.; Bai, Y.; A, L.; Gong, C.; batu, B.; Ni, S.; Ping, W.

2026-08-11 microbiology 10.64898/2026.08.08.743650 medRxiv
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Traditional Mongolian fermented foods have been extensively utilized for dietary regulation and the promotion of gastrointestinal health. However, spontaneous fermentation remains inherently unpredictable, leading to significant variations in microbial community dynamics, metabolite accumulation, and the consistency and quality of the final product. Drawing on the traditional preparation of Mongolian acidic foods, this study established a controlled production strategy for whole-wheat probiotic fermented soup (WWPFS) by combining enzymatic pretreatment with probiotic-directed fermentation. Physicochemical characterization, 16S rRNA gene-based microbial community profiling, LC-MS/MS-based untargeted metabolomics, safety evaluation, and an Escherichia coli-induced gut microbiota dysbiosis model were employed to optimize and comprehensively characterize the fermentation process of WWPFS. The optimized process established a reproducible fermentation system consistently dominated by Lactobacillus and Bacillus across independent fermentation batches. Compared with traditional spontaneous fermentation, probiotic-directed fermentation remodeled the physicochemical properties of the whole-wheat matrix, including carbon, nitrogen, phosphorus, sulfur, and mineral composition, and facilitated the accumulation of putatively annotated LC-MS/MS features, including DL-lactate, 1,4-D-xylobiose, diacetyl, and phenyllactic-acid-related features derivatives. Acute oral and 28-day repeated-dose toxicity evaluations showed no treatment-related adverse effects within the tested dose range and study duration. In the Escherichia coli-induced gut microbiota dysbiosis mouse model, microbial richness, diversity, and community structure differed among the experimental groups, and both low- and high-dose WWPFS groups showed significant shifts in overall gut microbial community composition relative to the model group after multiple-testing correction, together with directional recovery of selected model-responsive bacterial genera. Cross-system integration identified coordinated response patterns between fermentation-derived metabolite features and model-responsive gut bacterial taxa, supporting a potential metabolite-microbiota link in WWPFS-mediated gut microbiota modulation. In summary, probiotic-directed fermentation improved the controllability of the traditional Mongolian fermented food production process, reshaped its metabolic profile, and enhanced its potential to modulate the gut microbiota. These findings provide experimental evidence supporting the modernization of traditional Mongolian fermented foods and the development of probiotic-based functional foods.

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Apple scar skin viroid disease induced physicochemical and metabolic alterations in Apples

Chand, P.; Kumari, H.; Devi, E.; Kumar, R.; Watpade, S.; Masakapalli, S. K.

2026-07-29 plant biology 10.64898/2026.07.28.741181 medRxiv
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Apple scar skin disease (ASSD), caused by Apple scar skin viroid (ASSVd), is characterized by peel scarring, cracking, dappling, and fruit deformation, resulting in reduced fruit quality and marketability. Despite its economic importance, the physicochemical and metabolic alterations underlying disease progression remain poorly understood. To address this knowledge gap, apple fruits representing four stages of ASSD (healthy, lightly infected, moderately infected, and highly infected) were comprehensively characterized. ASSVd infection was confirmed by RT-PCR, amplicon sequencing, and phylogenetic analysis. Fruit morphology and quality attributes, including firmness, total soluble solids (TSS), pH, titratable acidity (TA), and total phenolic content (TPC), were evaluated. ASSVd infection significantly reduced fruit weight and firmness and altered TSS and TA, indicating progressive deterioration of fruit quality. To investigate the underlying metabolic changes, peel and pulp tissues were analysed separately using gas chromatography-mass spectrometry (GC-MS), while major soluble sugars were quantified by 1H nuclear magnetic resonance (1H NMR) spectroscopy. Integrated metabolomic analyses revealed distinct tissue-specific metabolic reprogramming during disease progression. Major soluble sugars declined significantly during early infection, followed by tissue-dependent recovery at later stages, whereas organic acids, amino acids, phenolics, lipids, polyols, and pentacyclic triterpenoids exhibited dynamic stage-dependent changes. Notably, lupeol accumulated progressively, whereas ursolic acid and oleanolic acid declined, indicating disease-associated alterations in host triterpenoid metabolism. Multivariate analyses demonstrated clear metabolic separation among disease stages. Lupeol, ursolic acid, and chlorogenic acid were identified as candidate discriminatory metabolites in the peel, whereas myo-inositol, chlorogenic acid, and aspartic acid were identified in the pulp. Collectively, these findings demonstrate that ASSD induces coordinated, tissue-specific physicochemical and metabolic reprogramming that compromises postharvest fruit quality and reshapes defence-associated metabolism. This study provides the first integrated metabolomic characterization of ASSD progression and identifies potential metabolic biomarkers for disease diagnosis and severity assessment. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=142 SRC="FIGDIR/small/741181v1_ufig1.gif" ALT="Figure 1"> View larger version (56K): org.highwire.dtl.DTLVardef@92e453org.highwire.dtl.DTLVardef@1cc2436org.highwire.dtl.DTLVardef@15d7e27org.highwire.dtl.DTLVardef@1056568_HPS_FORMAT_FIGEXP M_FIG C_FIG

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Electro-Fermentation of Grape Must via Candida tropicalis SY005: Accelerating Kinetics, Modulating Biochemical Pathway, and Improving Bio-active Content

Sharma, S.; Gautam, S.; Gaidher, M.

2026-07-25 microbiology 10.64898/2026.07.25.740694 medRxiv
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This study investigates electro-fermentation candida Tropicalis SY005 to address fermentation kinetics limitation during grape must fermentation. In comparison with non-stimulated control sample, EF substantially enhanced sugar depletion, TSS drop by day 3 and generated a strongly reduced state (ORP -100 to -143mV). The oxidation-reduction shift enhanced cellular NAD+ regeneration, reducing total fermentation duration from 264 h to 72 h. GC-MS analysis showed pronounced major characteristic volatile compound confirming substantial metabolic pathway shifts in flavor of glycolytic flux. Moreover moderate electric field promoted cellular membrane electropermeabilization substantially promoting bioactive extraction.

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Fermentation-Induced Molecular Remodeling in African Indigenous Tubers: Cassava and Cocoyam

Mendoza Cantu, A.; Lephatsi, M. M.; Aleshinloye, Y. A.; Phahlane, M. F.; Bamidele, O. P.; Madala, N. E.; Ludidi, N. N.; Bittremieux, W.; Gauglitz, J. M.; Tugizimana, F.

2026-06-09 biochemistry 10.64898/2026.06.05.730317 medRxiv
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Cassava and cocoyam are major dietary staples in sub-Saharan Africa, commonly processed by natural fermentation before consumption. Although fermentation reduces antinutritional compounds and improves food quality, its molecular effects remain poorly characterized. We used untargeted mass spectrometry-based metabolomics with a computational annotation pipeline to compare fermentation-induced molecular remodeling in the two tubers, which showed distinct responses. In cassava, 718 of 773 significant features (92.9%) were depleted, indicating a predominantly catabolic process. In cocoyam, the response was more balanced, with 385 of 1,013 features (38.0%) enriched, including di- and tripeptides consistent with proteolytic processing. Class analysis, molecular networking, and pathway enrichment revealed tuber-specific signatures: cassava was dominated by purine metabolism, whereas cocoyam showed stronger enrichment of amino acid pathways. Cyanogenic glycoside-related features were depleted, consistent with detoxification. Biotransformation prediction also suggested putative fermentation products absent from current databases, highlighting the under-characterized chemistry of these tubers.

10
Volatile profiling and estimated odor-activity analysis of commercial drug-type cannabis accessions

Babaei, M.; Goulet, C.; Torkamaneh, D.

2026-08-28 plant biology 10.64898/2026.08.27.747640 medRxiv
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Volatile organic compounds (VOCs) define the distinctive aroma of cannabis and critically influence consumer preference, cultivar authentication, and breeding programs. However, systematic characterization of VOC diversity across commercial drug-type cultivars remains limited. This study presents a comprehensive volatilomics-based phenotypic characterization of 165 commercial drug-type cannabis accessions using gas chromatography with flame ionization detection and mass spectrometry (GC-FID/MS). We identified 61 high-confidence VOCs assigned to three biosynthetic classes: terpenoids (n = 45), fatty acid-derived volatiles (n = 12) and amino acid-derived volatiles (n = 4), resolved into 12 subclasses. Analysis of variance revealed highly significant among-accession differences for all compounds (p < 0.001; 2 = 0.67-0.97), with repeatability estimates averaging 0.81 (range 0.50-0.95). Unsupervised clustering partitioned accessions into three distinct chemotypes (n = 90, 53, and 22), supported by principal component and t-SNE analyses. Machine learning-based feature selection identified a consensus panel of 12 discriminative compounds (camphene, -fenchene, sabinene, -terpinene, ({+/-})-limonene, -humulene, linalool, endo-fenchol, {Delta}3-carene, -thujene, {gamma}-terpinene and -phellandrene) that recovered the chemotype assignment of 32 of 33 held-out accessions. Estimated odor-activity screening ranked prenylthiol, -pinene, ({+/-})-limonene, linalool and myrcene highest among the odor-active compounds. All three chemotypes shared a prenylthiol-dominated core (67-77% of summed OAV) and were distinguished by the extent and nature of terpenoid modulation of that core: minimally modulated (Cluster ZERO), citrus-floral modulated (Cluster ONE) and pine-terpenic modulated (Cluster TWO). These findings indicate that volatile diversity in this panel can be summarized by three reproducible chemotypes, providing a quantitative basis for accession characterization and a foundation for future breeding and quality-assessment studies.

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Immunoengineered Chitosanase-Produced Chitosan Oligomers for Elevating Plant Resistance to Viral Infection

Khanahmadi, S.; Singh, R.; Ryll, J.; Nava Cruz, N. Y.; Cord-Landwehr, S.; Richter, C.; Rafieerad, A.; Moerschbacher, B. M.

2026-06-10 plant biology 10.64898/2026.06.09.731087 medRxiv
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Chitooligomers can act as plant biostimulants or biopesticides, but todays chitosan-based agro-biologics often lack sufficient efficacy. This is due to a lack of scalable production processes for structurally well-controlled chitosans combined with a limited understanding of structure-function relationships. Chitosans differ in their degree of polymerization (DP), fraction and pattern of acetylation (FA and PA). While the influence of DP and FA on antimicrobial and phytostimulatory properties is at least partially known, this is not yet the case for PA. PA can be partially controlled by using enzymatic rather than acid hydrolysis for oligomer production. We have used recombinant chitinases and chitosanases to hydrolyse a well-characterised chitosan polymer, and purified oligomers with different DP. We have structurally characterised the products and tested their abilities to protect tobacco from viral disease. Chitinase products were dominated by GlcNAc units at their reducing and non-reducing ends, with GlcN units dominating their centers, and v.v. for chitosanase products. While the chitinase-derived hydrolysates were inactive, the chitosanase-derived oligomers possessed elicitor and priming activities and protected plants from disease, and their activity increased with increasing DP. Clearly, the Bacillus chitosanase used is well-suited to set up a scalable production process for chitosan oligomers with promising agro-biologic properties. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=95 SRC="FIGDIR/small/731087v1_ufig1.gif" ALT="Figure 1"> View larger version (56K): org.highwire.dtl.DTLVardef@c312e9org.highwire.dtl.DTLVardef@10eaf99org.highwire.dtl.DTLVardef@12a937corg.highwire.dtl.DTLVardef@38dc8c_HPS_FORMAT_FIGEXP M_FIG C_FIG

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Impact of Solvent Extraction on Bioactive Properties of Lavandula x intermedia: Antibacterial, Antioxidant and Phenolic Content Analysis

GÜRSES, G.

2026-07-16 plant biology 10.64898/2026.07.11.737895 medRxiv
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Lavandula x intermedia (lavandin) is an economically important hybrid valued for its high essential oil yield; however, studies linking solvent polarity to its bioactivity and phenolic composition remain limited. This study evaluated the effects of nine extraction solvents on the antibacterial and antioxidant activities of L. x intermedia, determined total phenolic content (TPC), and examined the relationship between chemical composition and biological activity. Aerial parts were extracted by maceration. Antibacterial activity was assessed using the broth microdilution method against four bacterial strains, while antioxidant capacity was measured by the DPPH assay. TPC was determined using the Folin-Ciocalteu method, and phenolic compounds were analyzed via LC-MS/MS. Results showed that solvent polarity significantly influenced bioactivity. Diethyl ether extracts exhibited the highest TPC (267.65 mg GAE/g), strongest antioxidant activity (IC50: 72.26 {micro}g/mL), and notable antibacterial effects (MIC: 125 {micro}g/mL), especially against Gram-positive bacteria. A strong positive correlation (r = 0.887) was observed between phenolic content and antimicrobial activity. LC-MS/MS identified key compounds, including fumaric acid, resveratrol, and hydroxycinnamic acid. Overall, moderate-polarity solvents such as diethyl ether and methanol were most effective, highlighting L. x intermedia as a promising natural source for pharmaceutical and nutraceutical applications.

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Bittersweet dynamics from flowers to fruits: chemometric molecular networking reveals metabolic changes towards reduced toxicity over ontogeny in above-ground Solanum dulcamara chemotypes

Anaia, R. A.; Chiocchio, I.; van Dam, N. M.

2026-07-30 plant biology 10.64898/2026.07.29.741467 medRxiv
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Poisonous plants frequently deploy toxic metabolites in an organ- and ontogenetic-specific manner, yet the developmental dynamics of these plant specialised metabolites remain poorly understood. In the Solanaceae, steroidal glycosides (SGs), including steroidal glycoalkaloids (SGAs) and steroidal saponin glycosides (SSGs), are major defence metabolites with potent ecological and pharmacological activities. Here, we investigated how their metabolic profiles are reorganised during flower and fruit development in Solanum dulcamara using untargeted metabolomics and chemometric molecular networking. Non-metric multidimensional scaling (NMDS) using classified metabolite features recovered clear organ-specific and chemotype-specific segregation of samples, which was further strengthened when analyses were restricted to metabolomic features annotated as SGs. In flowers, orthogonal projections to latent structures discriminant analysis (OPLS-DA) separated both floral developmental stage and chemotype, demonstrating that developmental stage and inherited SG polymorphism represent independent axes of chemodiversity in flowers. Chemometric molecular networks showed pronounced diversification of hydroxycinnamate metabolism towards anthesis, including accumulation of caffeoylputrescine in flower buds and progressive acylation of spermidine conjugates across flower development. Upon anthesis, glycosylated hydroxycinnamates and flavonoids, and hydroxycinnamoyl-acylated flavonoid glycosides are accumulated. Fruit ripening followed a contrasting trajectory, in which SGAs were associated with unripe fruit pericarp, whereas ripe pericarp accumulated N- and O-acetylated SGA derivatives, oxidative deamination products, and predicted steroid degradation products, indicating stepwise detoxification of toxic steroidal glycosides during seed maturation. Together, these findings show that the poisonous chemistry in S. dulcamara is highly dynamic and developmentally orchestrated. Flowers accumulate structurally complex metabolites toward anthesis, including conjugates of hydroxycinnamates, whereas fruits metabolise toxic SGAs into less toxic SGs during ripening, linking metabolic remodelling to reproduction and seed dispersal.

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Higher Lipid Saturation in Well-Irrigated Georgia Cotton Plants: A Field-Based NMR Metabolomics Study

Patel, K.; Esselman, C. S.; Croy, J.; Gillis, M.; Rodrigues, P. A. P.; Simmons, A.; Borges, R. M.; Edison, A. S.; Snyder, W. E.

2026-06-10 plant biology 10.64898/2026.06.08.730374 medRxiv
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Cotton (Gossypium hirsutum) is an economically important crop, but it faces increasing pest outbreaks, especially in non-irrigated areas. In this study, 20 cotton farms using center-pivot irrigation were sampled in southern Georgia to assess chemical differences between non-irrigated and irrigated areas. Proton (1H) nuclear magnetic resonance (NMR) data were obtained from cotton leaves, and Principal Component Analysis (PCA) was performed to assess differences in chemical composition. Across all samples, farm site accounted for most of the variability, but within each farm site, the PCA scores plots showed clear separation between non-irrigated and irrigated conditions in 10 sites. Inspecting the PCA loadings revealed significant resonances resembling a lipid-like signal. After reverse-phase fractionation, we observed that many of these resonances appeared together in later fractions, suggesting a lipid, specifically a fatty acid such as linoleic acid. We hypothesized that differences in net lipid saturation level may drive separation between non-irrigated and irrigated samples. Six farm sites had a significantly or marginally significantly higher degree of unsaturation in irrigated samples, while one farm site had significantly higher unsaturation in non-irrigated samples. Our results indicate that drought stress likely affects lipid profile composition, which could be driving higher herbivorous pest densities in drought-stressed crops.

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Time-resolved volatile organic compound profiling enables non-invasive detection of phenological progression in soybean

Nakata, R.; Hiraga, S.; Ishimoto, M.

2026-08-28 plant biology 10.64898/2026.08.28.747781 medRxiv
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Background and aims Plant volatile organic compounds (VOCs) change dynamically with plant development and in response to environmental conditions. However, their potential as non-invasive indicators of phenological progression remains poorly explored. In this study, we developed a framework integrating automated VOC sampling, time-resolved VOC profiling, and machine-learning analysis for the non-invasive assessment of plant phenology. Using soybean (Glycine max (L.) Merr.), we investigated whether development-associated temporal variation in VOC emissions could delineate and predict developmental phases. Methods We collected VOCs daily under controlled environmental conditions from 16 to 43 days after sowing, spanning the transition from vegetative to reproductive stages, using an automated sampling system coupled with thermal desorption-gas chromatograph-mass spectrometer (TD-GC-MS). To characterise temporal changes in VOC profiles associated with phenological progression, we analysed the daily VOC data using a multi-step pipeline combining statistical filtering and similarity-based network analysis. We defined VOC-derived developmental phases from similarity patterns in the VOC profiles, then developed and evaluated machine-learning models to predict these phases. Key results Seven VOCs exhibited distinct phase-dependent dynamics, including green leaf volatiles and monoterpenes showing characteristic temporal changes during phenological progression. Network-based clustering of VOC profiles resolved five developmental phases closely aligned with conventional developmental stages. A machine-learning model predicted these phases from the VOC profiles with high predictive accuracy on independent test data, demonstrating that phenological progression could be quantitatively inferred from VOC emission patterns. Conclusions Our findings support VOC profiling as a reliable and non-invasive approach for assessing phenological progression in soybean. By extracting temporally structured VOC signals, this framework captures developmental information that may be difficult to obtain through visual observation alone, particularly after canopy closure. VOC profiling offers a practical tool for monitoring crop developmental dynamics and has broader potential for plant phenotyping and precision crop management.

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Green Synthesized Zinc Oxide Nanoparticles from Azadirachta indica Exhibit Enhanced Antibacterial, Antioxidant and Cytotoxic Activities

Manzoor, S.; Arif, T.; Rafiq, H.; Younas, S.; Akter, S.

2026-08-12 microbiology 10.64898/2026.08.12.744370 medRxiv
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Green synthesis of zinc oxide nanoparticles (ZnO NPs) offers a sustainable strategy for developing multifunctional antimicrobial nanomaterials. In this study, ZnO NPs were synthesized using Azadirachta indica leaf extract and characterized by UV-vis spectroscopy, FTIR, XRD, SEM, and GC-MS. The nanoparticles exhibited a characteristic absorption peak at 352 nm, a direct band gap of 3.07 eV, and hexagonal wurtzite crystallinity with an average crystallite size of approximately 32 nm. The biosynthesized ZnO NPs showed concentration-dependent antibacterial activity against Erwinia carotovora, producing inhibition zones of up to 25.9 mm. Mechanistic studies revealed significant membrane damage, evidenced by 4.77-fold and 5.62-fold increases in extracellular protein and amino acid leakage, respectively, with marked alterations in bacterial protein profiles detected by SDS-PAGE. The nanoparticles also exhibited strong antioxidant activity, achieving 89.4% DPPH radical scavenging, and induced dose-dependent cytotoxicity in HepG2 cells with an estimated IC50 of 124.8 g/mL. These findings demonstrate that neem-mediated ZnO nanoparticles possess potent antibacterial activity through membrane disruption while exhibiting promising antioxidant properties, highlighting their potential as eco-friendly nanomaterials for the management of bacterial soft rot and other phytopathogenic diseases.

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UPLC-ESI-MS based lipidomics revealed novel biomarkers in insulin receptor knockdown induced type 2 diabetes model of Drosophila

Kumar, P.; Fatima, Z.; Kumar, P.; Kumar, R.; Chauhan, B. S.; SRIKRISHNA, S.

2026-08-20 biochemistry 10.64898/2026.08.20.745875 medRxiv
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Type 2 diabetes (T2D) is a prevalent metabolic disorder affecting millions worldwide, characterized by insulin resistance and impaired glucose homeostasis. While mammalian models are widely used, Drosophila melanogaster provides a powerful alternative due to its conserved insulin signaling pathways, genetic tractability, and suitability for high throughput studies. In addition to glucose dysregulation, lipid metabolism plays a crucial role in T2D pathophysiology, as alterations in lipid composition contribute to insulin resistance and metabolic dysfunction. Lipidomic studies have emerged as an essential approach to identify metabolic signatures and potential biomarkers for disease progression and therapeutic targeting. In this study, T2D like model was established by inducing insulin resistance through knockdown of the insulin receptor in brain insulin-producing cells using the dilp2-Gal4>UAS-InRRNAi system. This genetic manipulation resulted in significant metabolic dysregulation, including elevated glucose, trehalose, and triacylglyceride levels, along with increased oxidative stress indicators. Additionally, mRNA expression analysis of key insulin signaling components, including insulin receptor substrate 1, dilp2, dilp3, dilp5, and phosphorylated Akt, further validated the model. To further investigate metabolic alterations, Lipid profiling was performed using ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) in non targeted LC-MS-based metabolomics approach to identify lipid biomarkers associated with T2D. Multivariate statistical analyses, including PCA and PLS-DA, revealed distinct lipid signatures between wild-type and T2D flies. Notably, specific phosphatidylglycerol species PG 34:0, PG 34:4, PA 38:3, PIP 38:1, PIP2 38:6, and LPS 24:0 demonstrated an area under the curve (AUC) of 1, indicating their strong reliability as lipid biomarkers for T2D diagnosis.

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Jasmonate-responsive group IX AP2/ERF transcription factors control the biosynthesis of benzylisoquinoline alkaloids

Yamada, Y.; Tatsumi, Y.; Inagaki, A.; Shitan, N.; Sato, F.

2026-08-31 plant biology 10.64898/2026.08.30.748054 medRxiv
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Although the biosynthetic pathways of benzylisoquinoline alkaloids (BIAs) have been extensively investigated in several plant species, their transcriptional regulatory mechanisms remain only partially understood. Jasmonate (JA)-responsive group IX APETALA2/Ethylene Responsive Factor (AP2/ERF) transcription factors (TFs) are well-known regulators of specialized plant metabolism, including the biosynthesis of various alkaloids. However, their specific roles in BIA biosynthesis remain largely elusive. Here, we isolated five novel group IX AP2/ERF TFs, designated Benzylisoquinoline alkaloid Jasmonate-responsive AP2/ERF (BJE1-5), from Coptis japonica. Phylogenetic analysis revealed that Benzylisoquinoline alkaloid Jasmonate-responsive AP2/ERF (BJE) proteins belong to subclades distinct from group IXa, which contains well-known AP2/ERF TFs involved in alkaloid biosynthesis. Transient expression analyses in C. japonica protoplasts demonstrated that certain BJEs, particularly CjBJE3 and CjBJE5, positively regulated BIA biosynthetic genes through a mutual regulatory network among BJE members. Moreover, CjBJE3 expression was regulated by CjbHLH1, a unique-type basic helix-loop-helix (bHLH) TF specific to BIA-producing plants. Furthermore, heterologous expression of CjBJE3 and CjBJE5 in cultured Eschscholzia californica cells significantly enhanced the overall BIA production, particularly by increasing end-product benzophenanthridine BIAs, highlighting several uncharacterized biosynthetic genes clustered in the genome. Our findings suggest that BIA-producing species have developed a specific regulatory network comprised of CjbHLH1 and BJE TFs, providing valuable clues for identifying novel biosynthetic enzymes.

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Pathogen-dependent biocontrol activity of Chlorella sorokoniana aqueous extracts against fungal and oomycete plant pathogens

Ciubotaru, R. M.; Claro, M.; Viana, C.; Figueiras, R.; Rosa, P.; Duarte, B.; Charnobay, A. C. R.; Rato, C.; Tedesco, S.; Andrade, S.; Coelho, L.; Gama, F.; Reis, M.; Correia, S.; Azevedo, C.

2026-08-06 plant biology 10.64898/2026.08.05.742703 medRxiv
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Fungal and oomycete plant pathogens are major drivers of yield losses worldwide and are spurring the search for sustainable alternatives to synthetic pesticides. Algae, in general, and microalgae, in particular, represent a promising source of bioactive compounds for crop protection. Despite this, their efficacy across different host-pathogen systems remains poorly characterised. This study evaluated the biocontrol potential of the aqueous extract of Chlorella sorokoniana against three economically important phytopathogens using complementary in vitro, ex vivo, and in planta assays. The strongest activity was observed against Magnaporthe oryzae, with the extract reducing fungal growth by approximately 70% in vitro, inhibiting appressorium formation by 55%, suppressing lesion development on detached rice leaves by more than 75%, and reducing rice blast severity by 64.5% as a preventive foliar treatment. In contrast, the extract showed little or no direct in vitro antifungal activity against Pythium ultimum and Rhizoctonia solani, yet it significantly reduced disease severity in planta by 13-37% and 48-55%, respectively. The contrasting responses among pathosystems suggest that C. sorokoniana aqueous extracts act through different mechanisms depending on the pathogen and the crop, combining direct antifungal activity against M. oryzae with plant-associated protective effects against soil-borne pathogens. These findings highlight the importance of evaluating candidate biocontrol products using complementary in vitro and in planta approaches, as laboratory antimicrobial assays alone may substantially underestimate their agricultural potential. The broad-spectrum protection achieved with an unrefined aqueous extract further supports C. sorokoniana as a promising source of sustainable crop protection products and provides a strong foundation for future mechanistic studies, formulation development, and field validation. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=115 SRC="FIGDIR/small/742703v1_ufig1.gif" ALT="Figure 1"> View larger version (45K): org.highwire.dtl.DTLVardef@394716org.highwire.dtl.DTLVardef@6a208corg.highwire.dtl.DTLVardef@17f0724org.highwire.dtl.DTLVardef@adda96_HPS_FORMAT_FIGEXP M_FIG C_FIG

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Discovery of a novel UV-absorbing mycosporine-like amino acid in Vertebrata lanosa using an expanded combinatorial structure database incorporating non-proteinogenic amino acids and organic solutes

Oberosler, A.; Hammerle, F. J.; Lanner, S.; Elgabarty, H.; Connan, S.; Pita, F.; Ballik, B.; Karsten, U.; Ganzera, M.

2026-08-26 plant biology 10.64898/2026.08.25.746913 medRxiv
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Mycosporine-like amino acids (MAAs) are among nature's most effective sunscreen compounds, capable of converting harmful ultraviolet radiation into harmless heat, and are widely distributed in marine organisms such as red macroalgae. Although decades of research have led to numerous discoveries, the rate of new MAA identifications has declined. To address this, we considerably expanded our previously developed combinatorial MAA database, increasing the number of covered structures tenfold. Following a comprehensive literature search for plausible but undescribed building blocks, the database now incorporates an extensive set of proteinogenic and non-proteinogenic amino acids, as well as other marine organic osmolytes, in combination with all (currently) known MAA scaffolds. This expanded resource was integrated into our identification platform, which combines UHPLC-VWD-HRMS2 analysis, feature-based molecular networking, and bioinformatics-driven annotation. Application of this updated workflow enabled the isolation and structural elucidation of a novel MAA, mycosporine-cysteinolic acid, from the red marine macroalga Vertebrata lanosa. Altogether, this study provides a valuable extension of the bioinformatics-based MAA screening pipeline, enhancing the annotation and discovery of novel MAAs in natural matrices.