Soybean underpins Brazil's agricultural, yet its sustainability is threatened by lepidopteran pests such as Anticarsia gemmatalis. Although insect-resistant cultivars have long been associated with the constitutive accumulation of quercetin-derived flavonols, the biochemical mechanisms underlying this resistance remain poorly understood. In particular, the role of flavonol O-methylation in enhancing plant defense has not been demonstrated. Here we combined metabolite identification, biological assays, and structure-based modeling to investigate flavonol-mediated resistance in soybean. The resistant genotype IAC 17 was found to accumulate not only rutin (quercetin 3-O-rutinoside; [M + H]+ = 611 Da) but also its O-methylated derivative isorhamnetin 3-O-rutinoside (narcissin; [M + H]+ = 625 Da). The 625 Da compound was purified by reversed-phase high-performance liquid chromatography and structurally confirmed by liquid chromatography-tandem mass spectrometry and nuclear magnetic resonance analyses. Chemical methylation of rutin using methyl iodide generated methylated derivatives that were evaluated in dietary bioassays with A. gemmatalis larvae. Both rutin and its methylated derivatives reduced survival, but O-methylation markedly enhanced toxicity: methylated rutin caused approximately 95% mortality within 5 days, whereas non-methylated rutin required about 17 days to reach comparable lethality. Molecular docking against the 70 most abundant larval midgut proteins revealed strong binding of both flavonols to proteases, cytochrome P450 enzymes, glutathione S-transferases, and membrane-associated proteins. These findings support a dual-ligand model in which rutin and narcissin cooperatively disrupt digestive and detoxification pathways in the insect midgut. The discovery of a constitutive flavonol O-methylation branch identifies narcissin as a potent defensive metabolite and provides mechanistic targets for breeding and metabolic engineering strategies aimed at developing soybean cultivars with improved resistance. © 2026 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Mycorrhizal phosphorus (P)-scavenging strategies are inefficient in severely P-impoverished environments; yet many mycorrhizal species occur here. How these species acquire P and how their acquisition coordinates with root and leaf traits remain unknown. We measured rhizosheath acid-phosphatases, leaf P-resorption efficiency and root and leaf economic traits and defence metabolites, such as phenolics and flavonoids, of Hibbertia hypericoides (Dilleniaceae) and H. racemosa in monoculture with arbuscular mycorrhizal fungal inoculation and in a mixture with P-mobilising Banksia attenuata (Proteaceae) with or without arbuscular mycorrhizal fungal inoculation. Phosphorus acquisition of both Hibbertia species was facilitated by B. attenuata, but through different interactions: H. hypericoides, non-mycorrhizal despite having been inoculated, used its roots, whereas H. racemosa, forming arbuscular mycorrhizal associations following inoculation, relied on mycorrhizal interactions with B. attenuata. This was linked to positions along the 'collaboration' dimension of root economic space and coordinated with root defence metabolites. Hibbertia species diverged along the leaf economic spectrum, with higher scores (more conservative strategy) negatively correlated with leaf P-resorption efficiency. We conclude that arbuscular mycorrhizal fungi play a key role in the P-acquisition strategy of H. racemosa. Root and leaf traits and rhizosheath acid-phosphatase activity efficiency interacted and contributed to the growth of both Hibbertia species.

Unlocking the mechanisms involved in the control of Bacillus amyloliquefaciens against postharvest soft rot of tomato fruits.

Gaultheria procumbens essential oil (GEO) is a natural source of defense inducers, as it is essentially composed of methyl salicylate (MeSA), a compound that can be converted in plant tissues into salicylic acid (SA), a central phytohormone regulating plant immunity. To gain insight into the response of plants to GEO treatment, we performed transcriptomic and metabolomic analyses of GEO-treated Arabidopsis thaliana plants. RNA sequencing analysis showed that fewer than 300 genes were differentially regulated, most of them belonging to functional categories related to receptors, signaling pathways, and transcription factors associated with plant defense or SA biosynthesis and signal transduction. Using the Arabidopsis SA biosynthesis–deficient sid2 line, we investigated MeSA metabolism in plant leaves following foliar GEO treatment. Quantification of MeSA, free SA, and total SA revealed that MeSA was mainly metabolized within 48 h after treatment and that GEO treatment led to the accumulation of conjugated forms of SA. Next, an untargeted metabolomic study was performed on GEO-treated leaves and on plants treated with the SA analog acibenzolar- S-methyl (Bion). This analysis revealed the accumulation of several benzoic acid derivatives upon GEO treatment but no accumulation of defense-related compounds such as indoles. By contrast, Bion treatment induced several indolic derivatives, including indole-3-carboxylic acid. This suggests that Bion directly triggered defense responses, whereas GEO treatment exerted a priming effect. Accordingly, metabolomic responses of A. thaliana leaves to Colletotrichum higginsianum infection showed a stronger accumulation of plant defense metabolites in GEO-treated leaves compared with untreated leaves. [Formula: see text] Copyright © 2026 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Microorganisms play crucial roles in the survival and fitness of their plant and insects hosts, including invasive species. The emerald ash borer (Agrilus planipennis, Fairmaire; EAB) is an invasive insect from Asia. It represents a significant threat to North American forest ecosystems, causing widespread mortality in susceptible native ash (Fraxinus) species. While previous studies have shown differences in specific plant defense metabolites between susceptible North American ash species and their more resistant Asian counterparts, widely targeted metabolite profiles and their interactions with phloem microbiota in response to EAB infestation has thus far received little attention. This study aimed to profile microbial communities associated with ash phloem and EAB larval guts and their relationship to ash phloem metabolites in three native susceptible North American ash species: F. pennsylvanica (green ash), F. nigra (black ash) and F. americana (white ash). Using metabarcoding to characterize the microbial communities associated with the larval gut and host tree phloem and widely targeted metabolomics to establish the first global metabolomic profile of phloem in these ash species, we examined interspecies differences in profiles and associations of ash phloem microbiota and metabolites in relation to EAB infestation. Multivariate analysis revealed that fungal communities were distinct in all ash species, while F. pennsylvanica (green ash) harbored bacterial communities distinct from black ash. Only black ash showed a phloem profile significantly associated with EAB attack symptoms and had the largest number of differentially abundant bacterial taxa. In contrast, larval gut bacterial communities from green ash were distinct from those in other ash species. Green ash displayed a distinct global metabolite profile from the other two species and had the highest number of differentially regulated metabolites, while black ash had the least. Green and white ash shared a strong upregulation of terpenoid compounds, several of which were among compounds significantly associated with microbial communities in green ash phloem or the EAB larval gut. Our results provide the first comparative analysis of phloem-associated microbial communities and metabolomes across three susceptible North American ash species and their response to EAB. We found that microbiota and metabolites in green ash showed a distinct response to EAB infestation from the other ash species and we identified specific metabolites exhibiting significant correlations with microbial communities in ash phloem or the EAB larval gut. These findings contribute novel insights into interspecies variability in host-associated microbial communities and metabolomes and their response to an invasive insect.

Time-series single-cell transcriptomics and spatial metabolomics reveal spatiotemporal tobacco leaf response to herbivory.

Drought stress limits growth, essential oil production, and menthol biosynthesis in peppermint (Mentha piperita). Plant growth-promoting rhizobacteria (PGPR), such as Pseudomonas fluorescens, can act as a biotic factor to enhance plant growth, antioxidant defense, and secondary metabolite accumulation under water stress. This study investigated the effects of P. fluorescens strain 18 inoculation on growth, antioxidant activity, essential oil composition, and menthol biosynthesis gene expression under three drought levels (30%, 65%, and 100% field capacity). Under drought stress at 65% field capacity, bacterial inoculation resulted in a 21.4% increase in shoot dry weight and a 29.8% increase in root dry weight. Bacterial inoculation also enhanced the activity of antioxidant enzymes peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) this reducing hydrogen peroxide (H2O2) and malondialdehyde (MDA) levels by 21.5% and 21%, respectively. Bacterial inoculation led to increases in essential oil (EO) content (13.5% in moderate stress, 9.3% in severe stress) and menthol content (20%, 17.6%, and 29.4% under severe, mild, and non-stress conditions, respectively). The expression of the menthonl reductase (mr) gene under moderate and severe stress conditions, compared to the control (non-stress) condition, was reduced by 4.6 and 2.9 times in the presence of bacteria and by 6.6 and 11.3 times in the absence of bacteria. The results indicate that pseudomonas fluorescens inoculation can effectively mitigate the adverse effects of drought stress and improve essential oil content and composition in peppermint by producing auxin ACC deaminase, enhancing water and nutrient uptake, and controlling pathogenic factors.

Lymantria obfuscata poses a significant threat to Salix alba plantations in Kashmir, creating an urgent need for sustainable, non-chemical pest management strategies. The present study aimed to evaluate the efficacy of salicylic acid (SA) as a plant defense inducer against this herbivore. In this experiment, Salix alba cuttings were subjected to three concentrations of SA (2, 3, and 4 mM) using spray and dip application methods prior to infestation with L. obfuscata larvae. Our results indicate that salicylic acid significantly reduced leaf defoliation in a dose-dependent manner; specifically, the dip method with 4 mM SA exhibited the lowest defoliation (13.10%) compared to 25.20% in control groups. SA treatment significantly suppressed larval and adult growth, with larvae feeding on 4 mM SA-treated dipped cuttings exhibiting an average weight of 2.82 mg versus 3.92 mg in the control treatment. Furthermore, salicylic acid treatment had a significantly positive impact on vegetative growth, enhancing leaf area (14.25 vs. 10.50 cm2 in control), plant height (37.20 vs. 30.80 cm), and root length (15.25 vs. 12.37 cm). Quantification of defensive metabolites revealed that the treatment significantly increased total phenol, total flavonoid, and total tannin content in SA-treated plants. GC-MS analysis confirmed that SA-treated plants accumulated higher endogenous SA levels, particularly in dipped plants (1.00 mg/g DW), compared to controls (0.10 mg/g DW). In conclusion, the application of 4 mM SA via the dip method effectively bolsters the morphological and biochemical defense mechanisms of Salix alba, offering a potent and sustainable strategy for managing Lymantria obfuscata infestations.

Glycoside hydrolase 1 (GH1) β-glucosidases were known to activate hormone conjugates and defense metabolites, yet their genomic organization and stress-response dynamics in wheat remained incompletely defined. We therefore performed an integrated characterization of TaBGLUs spanning phylogeny, gene structure and conserved motifs, subcellular localization, promoter cis-elements, Gene Ontology enrichment, protein-protein interaction networks, and targeted expression profiling. Wheat TaBGLUs partitioned into well-supported clades that shared canonical GH1 catalytic residues and a largely conserved motif scaffold. Subcellular localization predictions indicated predominant nuclear and chloroplast targeting, with a smaller cohort directed to secretory or endomembrane compartments. Promoters were enriched for light-responsive, hormone-related (ABA, JA/SA, auxin, GA) and stress-associated (MYB/WRKY, heat, low temperature) cis-elements, and functional annotations were consistent with roles in carbohydrate and cell-wall metabolism, hormone homeostasis, and defense. Network analysis revealed a densely connected TaBGLU submodule embedded within broader carbohydrate and defense interaction networks, suggesting coordinated or cooperative functions. Expression profiling under cold, drought, and combined drought and cold demonstrated broad stress inducibility, with early activation detected by 6 h, cold-responsive maxima typically at 12 h, drought-responsive peaks predominating at 24 h, and combined stress eliciting both earlier and more sustained expression maxima between 12-24 h. Representative strongly responsive genes included TaBGLU20, TaBGLU44, TaBGLU6, and TaBGLU23, which showed pronounced late induction under combined stress, TaBGLU30, which exhibited an earlier combined-stress peak, and TaBGLU12, which displayed a marked late drought-specific response. Taken together, this integrated genomic, regulatory, and expression atlas refined the wheat BGLU repertoire relative to previous gene model inventories, highlighted candidate TaBGLUs with central network positions and strong stress inducibility, and provided concrete entry points for functional validation and breeding for improved stress resilience.

Plant-associated microbial communities provide crucial protection against pathogens. Specialized metabolites play key roles in plant-microbe and microbe-microbe interactions and, ultimately, in plant health; however, the molecular mechanisms underlying their plant-protecting properties remain largely unknown. Nutrient deficiency (e.g., iron) on leaf surfaces creates intense competition among microbes, driving both antagonism and cooperation. Using a gnotobiotic Arabidopsis thaliana model and a synthetic leaf microbial community, we show that community stability and plant protection depend on cooperative siderophore exchange between the basidiomycete yeast Rhodotorula kratochvilovae and commensal Pseudomonas species. Removal of Pseudomonas caused a strong shift in the community metabolome and accumulation of the yeast siderophore rhodotorulic acid (RA). RA selectively promoted the growth of commensal Pseudomonas via TonB-dependent transporters, which are absent in pathogenic Pseudomonas strains. Inactivation of these transporter genes abolished RA uptake, destabilized the synthetic community, and eliminated protection against Pseudomonas syringae infection. RA and Rhodotorula also induced host iron-deficiency and jasmonate-related defense metabolites, linking microbial cooperation to plant stress responses. These findings reveal that microbial siderophore exchange acts as a key mechanism that maintains stability in the phyllosphere microbiome. Rather than solely promoting competition, iron-binding compounds can serve as cooperative currencies that align microbial fitness with host protection.

Abstract Tomato production worldwide is threatened by various biotic stresses, including fungal and bacterial pathogens, which significantly reduce yield and fruit quality. Seed biopriming has become a promising and sustainable alternative to traditional chemical controls because it establishes beneficial plant-microorganism interactions at the early stage of tomato growth, allowing tomato plants to activate defense responses more quickly and effectively when attacked by pathogens such as Fusarium oxysporum f.sp . lycopersici . This increased resistance is achieved through strengthening Pattern-triggered immunity (PTI) in tomato plants, adjusting key hormone pathways, such as salicylic acid (SA), jasmonate/ethylene (JA/ET), and abscisic acid (ABA), and increasing major antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD), which work together to reduce oxidative damage. Additionally, tomato seed biopriming activates the phenylpropanoid pathway and boosts lignin production, reinforcing cell wall strength and increasing levels of defensive secondary metabolites. Importantly, biopriming can establish epigenetic memory, including DNA methylation and histone modification patterns, allowing defense readiness to persist beyond the initial stimulus. Beyond resistance, seed biopriming enhances tomato root development, nutrient acquisition, and fruit nutritional quality, contributing to plant resilience and yield stability. Overall, seed biopriming represents a cost-effective and eco-friendly strategy that supports sustainable tomato production systems.

In coevolutionary interactions, host plants accrue novel chemical defenses that specialist herbivores counter by detoxification and sometimes sequestration. We recently found unusual nitrogen- and sulfur-containing (N,S-) cardenolides in some milkweeds—highly toxic compounds that monarch butterflies ( Danaus plexippus ) detoxify during sequestration. We hypothesized that the N,S-cardenolides in Asclepias curassavica (uscharin and voruscharin) would reduce caterpillar performance and sequestration more than other abundant related cardenolides (15-hydroxy-calotropin, frugoside, calactin). Cardenolides generally increased feeding relative to controls, but voruscharin was not stimulatory and substantially reduced growth efficiency. Exposure to either N,S-cardenolide produced the lowest sequestration and reduced sequestration efficiency, consistent with detoxification limiting toxin retention. We next tested whether toxin mixtures impose additional costs relative to individual compounds. We prepared two mixtures, one with equal concentrations of five cardenolides and a ‘realistic mixture’ reflecting natural proportions. Relative to the average of single compounds, mixtures reduced feeding, growth, sequestration, and sequestration efficiency, indicating phytochemical diversity effects exceeded expectations from an additive model. The two mixtures similarly reduced growth, but feeding on the realistic mixture yielded the lowest sequestration. We conclude that coevolution can produce highly specialized defense metabolites such as N,S-cardenolides that thwart even sequestering herbivores, and that phytochemical mixtures strengthen plant defense.

In coevolutionary interactions, host plants accrue novel chemical defenses that specialist herbivores counter by detoxification and sometimes sequestration. We recently found unusual nitrogen- and sulfur-containing (N,S-) cardenolides in some milkweeds-highly toxic compounds that monarch butterflies (Danaus plexippus) detoxify during sequestration. We hypothesized that the N,S-cardenolides in Asclepias curassavica (uscharin and voruscharin) would reduce caterpillar performance and sequestration more than other abundant related cardenolides (15-hydroxy-calotropin, frugoside, calactin). Cardenolides generally increased feeding relative to controls, but voruscharin was not stimulatory and substantially reduced growth efficiency. Exposure to either N,S-cardenolide produced the lowest sequestration and reduced sequestration efficiency, consistent with detoxification limiting toxin retention. We next tested whether toxin mixtures impose additional costs relative to individual compounds. We prepared two mixtures, one with equal concentrations of five cardenolides and a 'realistic mixture' reflecting natural proportions. Relative to the average of single compounds, mixtures reduced feeding, growth, sequestration, and sequestration efficiency, indicating phytochemical diversity effects exceeded expectations from an additive model. The two mixtures similarly reduced growth, but feeding on the realistic mixture yielded the lowest sequestration. We conclude that coevolution can produce highly specialized defense metabolites such as N,S-cardenolides that thwart even sequestering herbivores, and that phytochemical mixtures strengthen plant defense.

In coevolutionary interactions, host plants accrue novel chemical defenses that specialist herbivores counter by detoxification and sometimes sequestration. We recently found unusual nitrogen- and sulfur-containing (N,S-) cardenolides in some milkweeds—highly toxic compounds that monarch butterflies (Danaus plexippus) detoxify during sequestration. We hypothesized that the N,S-cardenolides in Asclepias curassavica (uscharin and voruscharin) would reduce caterpillar performance and sequestration more than other abundant related cardenolides (15-hydroxy-calotropin, frugoside, calactin). Cardenolides generally increased feeding relative to controls, but voruscharin was not stimulatory and substantially reduced growth efficiency. Exposure to either N,S-cardenolide produced the lowest sequestration and reduced sequestration efficiency, consistent with detoxification limiting toxin retention. We next tested whether toxin mixtures impose additional costs relative to individual compounds. We prepared two mixtures, one with equal concentrations of five cardenolides and a ‘realistic mixture’ reflecting natural proportions. Relative to the average of single compounds, mixtures reduced feeding, growth, sequestration, and sequestration efficiency, indicating phytochemical diversity effects exceeded expectations from an additive model. The two mixtures similarly reduced growth, but feeding on the realistic mixture yielded the lowest sequestration. We conclude that coevolution can produce highly specialized defense metabolites such as N,S-cardenolides that thwart even sequestering herbivores, and that phytochemical mixtures strengthen plant defense.

Integrated host-pest proteomics revealed that chickpea resistance to Helicoverpa armigera involves early jasmonic acid signaling and linoleic acid-derived pro-toxins from crop wild relatives, providing molecular targets for breeding insect-resilient cultivars. Chickpea (Cicer arietinum L.), being a vital food legume, suffers severe yield reductions due to the pod borer Helicoverpa armigera. Despite extensive breeding efforts, durable resistance has remained elusive due to limited insights into the molecular basis of host-pest interactions. To address this gap, a first-of-its-kind integrated host-pest proteomic analysis in chickpea was performed to unravel the molecular mechanisms underlying natural insect resistance. Using untargeted LC-MS/MS, the proteomes resistant (ICCV506EB), susceptible (ICC3137) and a resistant crop wild relative (CWR's) (IG73016, C. cuneatum), along with larvae feeding on these genotypes, were simultaneously profiled. Resistant genotypes elicited a rapid, multi-layered defense response involving jasmonic acid (JA)-mediated signaling, transcriptional reprogramming, and fatty acid-derived secondary metabolites. In turn, H. armigera activated detoxification enzymes, proteolytic modulation, and behavioral countermeasures. Strikingly, larvae feeding on resistant CWRs failed to overcome defenses, as linoleic acid (LA) derivatives are suggested to act as pro-toxin-like factors, adversely affecting larval survival, digestion, growth, and development. The findings reveal the dynamic defense-counter-defense interplay between chickpea and H. armigera. This interplay highlights the key biomolecular nodes associated with durable resistance. This study provides correlative evidence suggesting that LA-derived defense metabolites may function as potential pro-toxin-like compounds and establishes CWRs as a rich source of resistance traits. Importantly, enhancing early JA-pathway activation through molecular breeding or biotechnology could accelerate the development of insect-resilient chickpea cultivars, thereby boosting crop productivity and sustainability.

Lupinus termis (Forssk.) is a valuable leguminous plant, prized for its medicinal and nutritional properties. This study aimed to investigate the biochemical and physiological responses of lupine to elicitation using biosynthesized nanoparticles (NPs) and a plant-derived extract. Iron oxide (Fe₂O₃) and calcium hydroxide (Ca(OH)₂) NPs were synthesized via rosemary (Salvia rosmarinus Spenn.) leaf polyphenols. The efficacy of green synthesized NPs was compared to rosemary extract as separate elicitor treatments in a greenhouse experiment to increase plant growth and metabolism. Both the NPs and rosemary extract significantly enhanced growth, biomass and photosynthetic attributes, whereas the NPs induced greater growth activity. All treatments reduced malondialdehyde levels while increasing hydrogen peroxide, ascorbic acid, total antioxidant activity, and the activities of polyphenol oxidase and peroxidase. Additionally, Ca(OH)₂ NPs increased the levels of key polyphenols constituents (ellagic acid, syringenic acid and kaempferol); whereas Fe₂O₃ NPs increased quercetin and myricetin accumulation. Rosemary treatment induced the highest levels of chlorogenic acid and naringin. Both NPs and rosemary extract increased key alkaloids (lupinine and angustifoline) to remarkable levels, which correlated with secondary metabolism and PAL activation. Furthermore, NPs boosted endogenous auxins (IAA) and gibberellins (GA) via modulating abscisic acid (ABA) and salicylic acid (SA) levels, thereby improving hormonal homeostasis and growth. Because of its bioactive phenolic derivatives, rosemary markedly increased SA levels while lowering GA and ABA, which strengthened plant defense. These findings demonstrate that green-synthesized Fe₂O₃ and Ca(OH)₂ NPs, as well as rosemary extract, improved L. termis growth, stress tolerance, and nutraceutical compounds.

GhAAP3 negatively regulates cotton resistance to Helicoverpa armigera by downregulating key defense pathways, impairing the plant's chemical defense, and enhancing nutritional suitability for herbivorous pests. Cotton (Gossypium spp.), a fundamental global fiber crop, is highly susceptible to insect pests, including Helicoverpa armigera. Amino acid/auxin permeases (AAAPs) are crucial membrane transporters involved in plant development and stress responses. In this study, we overexpressed amino acid permease 3 (GhAAP3) in upland cotton to evaluate its function in defense against H. armigera. The larvae fed on GhAAP3-overexpressing plants (AP3-1 and AP3-2) exhibited higher growth and feeding by 95.85% and 220.83%, respectively, compared to larvae fed on wild-type (WT) plants. Transcriptomic analysis revealed global downregulation of key defense pathways, including jasmonic acid (JA) biosynthesis and signaling, mitogen-activated protein kinase (MAPK) signaling, and phenylpropanoid and terpenoid biosynthesis pathways, in AP3. Consistently, GhAAP3 overexpression caused a marked reduction in JA-related hormones (JA, methyl jasmonate (MeJA), and jasmonic acid-isoleucine (JA-Ile)) by 45.75-87.41% and key defensive secondary metabolites (flavonoids and gossypol) by 26.35-56.38%. Conversely, free amino acids and soluble sugar contents increased significantly in AP3-overexpressing transgenic plants. Our findings demonstrate that GhAAP3 negatively regulates cotton resistance against H. armigera by downregulating key defense-related phytohormones and secondary metabolites, while concurrently elevating amino acid and sugar levels. This together impairs the plant's chemical defense and enhances its nutritional suitability for herbivorous pests.

Dracaena cambodiana Pierre ex Gagnep. is divided into two distinct groups: the Yunnan clade with soft leaves (D. cambodiana A) and the Hainan clade with hard leaves (D. cambodiana B). This species is the key plant source of dragon’s blood, a well-known traditional Chinese medicine derived from the defensive metabolites of Dracaena species, with flavonoids as its major bioactive components. Dihydroflavonol 4-reductase (DFR) plays a pivotal role in flavonoid biosynthetic pathway. In this study, we identified 19 DFR genes (designated as DcDFRs) from the reference genome of D. cambodiana, which are distributed across six chromosomes and phylogenetically classified into four subfamilies. Comprehensive analyses of their chromosomal localization, sequence homology, gene structure, and phylogenetic relationships revealed two distinct tandemly duplicated gene clusters (TDGCs), designated as TDGCs-1 and TDGCs-2. Notably, TDGCs-1, comprising DcDFR1–DcDFR5 and localized on chromosome 5, exhibits conserved tissue-specific co-expression patterns and coordinated transcriptional responses to wound stress across two distinct D. cambodiana accessions (D. cambodiana A and D. cambodiana B). Its expression levels are positively correlated with both the duration of stress induction and flavonoid accumulation, suggesting a critical role in flavonoid metabolism and wound defense responses. Unlike TDGCs-1, TDGCs-2 does not show typical co-expression patterns under wound stress in D. cambodiana A, which implies that the two tandemly duplicated gene clusters have both overlapping and distinct biological functions. This study reveals the secondary metabolic pathways triggered by particular environmental stresses and provides a theoretical foundation for future investigations into the artificial induction technology of dragon’s blood.

Introducing insect biocontrol agents sourced from a plant’s native range is an effective, sustainable management strategy for invasive plants. However, not all biocontrol programmes achieve the desired outcome because control agents either fail to establish or are ineffective. Heather beetle Lochmaea suturalis (Coleoptera: Chrysomelidae), introduced from the United Kingdom (UK) to New Zealand (NZ) to control the invasive shrub Calluna vulgaris (heather), was difficult to establish and achieved poor population growth rates and expansion relative to its conspecifics in its native UK range. Poor performance in biocontrol is often attributed to various abiotic or biotic factors but seldom considers alterations to a target plants biochemical phenotype. A recent study revealed, heather has a significantly different biochemical profile in NZ compared with the UK, between which there is considerable difference in ultra-violet (UV) radiation. UV is known to drive plant biochemical change, including defensive secondary metabolites and we hypothesized that this factor could enhance heathers’ defensive capability leading to poor biocontrol agent performance. Testing this hypothesis involved exposing heather plants to 20% and 95% UV attenuating screens and using metabolomics to measure plant secondary metabolite responses. Our results demonstrate significant alterations to many compounds derived from the shikimate-phenylpropanoid pathway. However, a bioassay revealed no impact on prepupal weight or larval survival of the biocontrol agent L. suturalis. We discuss and explore possible reasons for this outcome, the magnitude and impact of UV-induced biochemical changes on plant-insect interactions and the potential of metabolomics to support weed biocontrol.

Microbial communities play essential roles in mediating plant defenses against insect pests. However, how host-associated microbiota and metabolites jointly respond to bark beetle infestation remains largely unexplored. Here, we integrated microbiome and metabolome profiling to elucidate how Pinus tabuliformis regulates its phloem and rhizosphere responses under varying levels of Dendroctonus valens infestation. Both bacterial and fungal diversity, as well as the relative abundance of dominant taxa such as Erwinia and Pseudoxanthomonas, shifted significantly with infestation intensity. Concurrently, key plant defense metabolites—including terpenoids, jasmonates, and polyphenols—were markedly elevated. Pathway enrichment analysis indicated that the phloem was characterized by enhanced phenylpropanoid and flavonoid biosynthesis, whereas the rhizosphere soil accumulated terpenoids and polyketides, implicating both compartments in resistance modulation. In the phloem, differential bacterial and fungal taxa displayed distinct positive and negative correlations with phenylpropanoid intermediates and downstream derivatives, while in the rhizosphere, bacteria from Bacillota and fungi such as Candida and Ogataea were strongly linked to diterpenoids, sesquiterpenoids, flavonoids, and indole derivatives. These findings demonstrate that P. tabuliformis mounts a compartment-specific, microbiome-associated metabolic response to D. valens infestation, providing new insights into the ecological roles of symbiotic microbiota in plant defense and offering a mechanistic foundation for microbe-based pest management strategies.