Plant Physiol. Biochem. [JOURNAL]
Sun
200 papers
Functional characterization and catalytic mechanism of a C/N-selective methyltransferase MaMT4 involved in 1-deoxynojirimycin-type alkaloids biosynthesis in mulberry leaves.
He L, Pi J, Liao Y … +5 more , Fan J, Wang L, Wei Y, Ouyang Z, Wan J
Plant Physiol Biochem · 2026 Jun · PMID 42160835 · Publisher ↗
1-Deoxynojirimycin (DNJ)-type alkaloids represent the hallmark hypoglycemic bioactive components in mulberry leaves (Morus alba L.). However, the methylation steps involved in their biosynthesis, particularly the roles a...
1-Deoxynojirimycin (DNJ)-type alkaloids represent the hallmark hypoglycemic bioactive components in mulberry leaves (Morus alba L.). However, the methylation steps involved in their biosynthesis, particularly the roles and catalytic mechanism of plant C-methyltransferases, remain poorly understood. In this study, through further mining of transcriptome data, we screened and identified two methyltransferase genes significantly correlated with DNJ content in mulberry leaves (P < 0.05). Enzymatic assays demonstrated that MaMT4 catalyzes the methylation of piperidine at the C2 position to form 2-methylpiperidine, while also mediating the N-methylation of piperidin-4-ol to generate 1-methylpiperidin-4-ol, revealing an unusual substrate-dependent C/N-position methylation selectivity. Enzyme kinetic analysis revealed that MaMT4 exhibits higher catalytic efficiency and substrate affinity for piperidine than toward piperidin-4-ol. Furthermore, in vivo gene overexpression and silencing experiments confirmed that MaMT4 positively regulates the accumulation of DNJ-type alkaloids in mulberry leaves. To elucidate the catalytic mechanism of MaMT4, molecular docking, site-directed mutagenesis, and in silico mutational analyses were performed. The results indicate that MaMT4 can modulate the relative contributions of hydrogen-bonding networks and hydrophobic interactions in response to subtle changes in substrate polarity and steric properties, thereby selectively recognizing and accommodating structurally diverse substrates. In particular, F363 and I80 were identified as critical residues responsible for this property. Together, these findings identify MaMT4 as a key methyltransferase involved in DNJ-type alkaloid biosynthesis and provide new insight into the catalytic mechanism and functional diversity of plant methyltransferases.
Single-cell and spatial transcriptomics reveal the regulatory continuum from initial substrates to storage compounds during wheat grain development.
Fan J, Xue Q, Li J … +16 more , Liu Y, Liu F, Li Z, Wang J, Xu Y, HengRui Zhang, Zhu Z, Zhang M, Chen C, Li T, Liu X, Shi X, Wang C, Zhao J, Ji W, Deng P
Plant Physiol Biochem · 2026 Jun · PMID 42160834 · Publisher ↗
Wheat grain development determines yield and quality but involves complex spatial organization across genetically distinct maternal and filial tissues. Dissecting the regulatory architecture of this composite organ requi...
Wheat grain development determines yield and quality but involves complex spatial organization across genetically distinct maternal and filial tissues. Dissecting the regulatory architecture of this composite organ requires approaches that resolve both cellular identity and spatial context. Here, we integrate single-nucleus RNA sequencing with spatial transcriptomics to construct a high-resolution spatiotemporal atlas of wheat grain development at the milk stage (25 days after flowering, 25 DAF). This integrated framework resolves 13 transcriptionally and spatially distinct cell populations spanning maternal tissues, endosperm, aleurone layer, and embryo. By combining cell-resolved and in situ expression profiles, we uncover pervasive subgenome-biased transcription, with pronounced B subgenome dominance in grain tissues. Spatially informed regulatory and hormone signaling analyses reveal stage-specific maternal-filial communication and coordinated auxin, abscisic acid, and gibberellin crosstalk. Co-expression network integration further identifies NAC transcription factors as central regulators linking storage metabolism, programmed cell death, and grain maturation. Our study demonstrates the power of integrating single-nucleus and spatial transcriptomics to resolve regulatory complexity in polyploid crop organs and provides a foundational resource for dissecting wheat grain development and improving yield and quality.
Mutations in AtpB and LexA confer temperature tolerance in an evolved Synechocystis sp. PCC 6803 strain resistant to high temperature and light.
Wang W, Pan K, Gao J … +3 more , Chen L, Sun T, Zhang W
Plant Physiol Biochem · 2026 Jun · PMID 42155158 · Publisher ↗
Outdoor-scale cultivation of cyanobacteria can encounter multiple stresses, including high temperature (HT) and excessive light (HL) exposure. In this study, we obtained HL and HT tolerant strains through adaptive labora...
Outdoor-scale cultivation of cyanobacteria can encounter multiple stresses, including high temperature (HT) and excessive light (HL) exposure. In this study, we obtained HL and HT tolerant strains through adaptive laboratory evolution. The evolved strains (HLHT-1, HLHT-2, and HLHT-3) exhibited lower levels of ROS, improved photosynthetic performance and pigment levels, and greater dry weight and glycogen compared to the wild-type strain under HT and HL conditions. Comparative transcriptome analysis suggested that HLHT-2 possibly achieved high temperature resistance by up-regulating the expression of oxidative phosphorylation pathway or down-regulating the expression of peptidases and inhibitors pathway. Whole-genome re-sequencing identified a total of six mutations in the 3 evolved strains relative to the parent strain. Via gene knockout, inhibition, and overexpression of the mutated genes in parent strain, we found two genes contributing the HT tolerance including sll1626 encoding the SOS response inhibitory protein LexA, and slr1329 encoding the ATP synthase subunit AtpB. These findings provide valuable insights into the genetic basis of cross-stress tolerance in photosynthetic microorganisms and, given the shared evolutionary heritage between cyanobacteria and plant chloroplasts, may also inform strategies for engineering stress-resilient plants to enhance productivity under challenging environmental conditions.
GABA and ABA-mediated mitigation of salt stress-induced oxidative damage by modulating secondary metabolites, defense metabolism, and photosynthetic pathways in wheat.
Kumari S, Khatoon S, Pratap A … +2 more , Rehman MT, Khan MIR
Plant Physiol Biochem · 2026 Jun · PMID 42150449 · Publisher ↗
Wheat crop vulnerability to varying salinity levels is escalating, significantly endangering global food security. To resolve these challenges, studies on the role of signaling molecules in salt stress could be an impera...
Wheat crop vulnerability to varying salinity levels is escalating, significantly endangering global food security. To resolve these challenges, studies on the role of signaling molecules in salt stress could be an imperative tool for sustaining wheat productivity. While the individual roles of γ-aminobutyric acid (GABA) and abscisic acid (ABA) in stress mitigation are well-known, this study demonstrates their synergistic orchestration of the metabolic networks. In this study, GABA and ABA applications stabilize cellular redox homeostasis through antioxidants' activation and lignification, which has reduced the occurrence of oxidative stress biomarkers, including lipid peroxidation. Further, GABA and ABA modulated the GABA shunt pathway, and adjusted the carbon anabolism (Calvin cycle), catabolism (glycolysis pathway) and amphibolic (tricarboxylic acid [TCA] cycle) events, leading to the accumulation of photosynthesis-end products (starch and sucrose) under salt stress. Hence, the co-application of GABA and ABA has systematically reconfigured sugar and starch metabolism, providing a robust metabolic framework for salt tolerance in wheat. Additionally, nitric oxide (NO) biosynthesis induced upon GABA and ABA co-application has aided in regulating the ionic homeostasis under salt stress. The role of GABA and ABA biosynthesis in salt tolerance has been also substantiated through employing aminooxyacetic acid and fluridone (GABA and ABA biosynthesis inhibitors, respectively). Consequently, these findings establish that the maintenance of an optimal redox state is a prerequisite for sustaining the carbon metabolic flux required for the optimal grain yield under salt stress. By integrating the synergistic GABA-ABA signaling pathways with the carbon metabolic network, this study provides a specific physiological and molecular blueprint for developing "salt-smart" wheat cultivars through targeting the potential plant pathways to balance source-sink partitioning under salt stress.
A regulatory network revealing spatial distribution differences of alkaloids, flavones, and carbohydrates in Fritillaria thunbergii bulbs by multi-omics analysis.
Wang L, Weng W, Zhou Z … +6 more , Liang B, Wang S, Hu X, Zhu H, Wang H, Sui N
Plant Physiol Biochem · 2026 Jun · PMID 42150448 · Publisher ↗
The secondary metabolites in the bulbs of Fritillaria species display distinct spatial distribution patterns, yet the underlying mechanisms remain unclear. In this study, bulbs of Fritillaria thunbergii were divided into...
The secondary metabolites in the bulbs of Fritillaria species display distinct spatial distribution patterns, yet the underlying mechanisms remain unclear. In this study, bulbs of Fritillaria thunbergii were divided into inside (IS) and outside (OS) layers. Integrated physiological, transcriptomic, metabolomic, and microbiomic analyses were performed to elucidate the spatial regulation of alkaloids, flavonoids, and carbohydrates. The OS was significantly enriched in secondary metabolites, with total alkaloid, peimine, and total flavonoid contents being approximately 1.18-, 1.28-, and 1.24-fold higher, respectively, than those in the IS. In contrast, carbohydrates mainly accumulated in the IS, where sucrose and starch levels were 1.37- and 2.18-fold higher than those in the OS. Transcriptomic analysis revealed that carbohydrate enrichment in the IS was associated with the upregulation of sucrose synthase (SUS) and hexokinase (HK) genes, and the downregulation of β-amylase3 (BAM3) and invertase (INV). In the OS, genes related to steroidal alkaloid biosynthesis, including 3-hydroxy-3-methylglutaryl-CoA synthase (HMGCS), 1-deoxy-D-xylulose-5-phosphate reductoisomerase (DXR), and farnesyl-diphosphate farnesyltransferase 1 (FDFT1), as well as flavonoid biosynthesis genes phenylalanine ammonia-lyase (PAL), 4-coumarate-CoA ligase (4CL), and cytochrome P450 monooxygenase CYP75B1 (CYP75B1), were upregulated. Moreover, bacterial taxa enriched in the OS, such as Actinomycetota and Ruminococcus, correlated positively with alkaloid accumulation, while the fungal genus Aspergillus was potentially associated with flavonoid regulation. Overall, the multi-omics insights provided here not only offer theoretical support for refined, region-specific processing of Zhejiang Fritillaria bulbs but also open new avenues to improve medicinal quality by manipulating host gene expression and microbial community composition.
The emerging insights on signaling molecule-mediated hyperaccumulation: Unlocking potential in metal-stressed plants with phytoremediation applications.
Sharma P, Iqbal MZ, Chandra R
Plant Physiol Biochem · 2026 Jun · PMID 42150447 · Publisher ↗
Phytoremediation, which involves plants and their associated microbiome, is a sustainable remediation strategy for removing, stabilizing, or degrading contaminants in the ecosystem. The technology revolves around hyperac...
Phytoremediation, which involves plants and their associated microbiome, is a sustainable remediation strategy for removing, stabilizing, or degrading contaminants in the ecosystem. The technology revolves around hyperaccumulators that tolerate and remove contaminants through their physiological and molecular mechanisms that are facilitated by various signaling molecules [reactive oxygen species (ROS), phytohormones, calcium ions (Ca), nitric oxide (NO), and electrophysiological signals]. This review aims to define the phenomenon of phytoremediation, enumerate its types, and highlight its limitations, with an emphasis on the role of hyperaccumulator plants in environmental remediation. The major focus is on the signaling molecules-regulated molecular mechanisms of metal uptake, translocation, chelation, sequestration, and antioxidant defence. Remediation processes are optimized by regulatory networks resulting from phytohormonal cross-talk. The transgenic and CRISPR/Cas9 technologies can significantly improve the hyperaccumulator capacity through gene overexpression and gene editing of those encoding the biosynthesis of signaling molecules. The processes, phytostabilization, phytoextraction, and the microbial breakdown of organic pollutants by plants, have shown the most removal of contaminants in the in-situ experiments. The research gaps are the complexity of the pathway, the variability of the environment, and a detailed research plan, focusing on electrophysiology and the integration of Artificial intelligence/Machine learning. The concept of coupling microbial synergy, nanotechnology, and portable monitoring can accomplish the phytoremediation shift from the lab to the field. Signaling molecules can be utilized by hyperaccumulators to effectively address the global problem of contamination, thereby enabling the development of renewable and environmentally friendly solutions for the eco-restoration of contaminated sites.
Glutamine synthetase in root tips promotes root elongation via facilitating nucleotide metabolism under nitrogen deficiency.
Wei Y, Zhang X, Wang S … +9 more , Song W, Zhang X, Wang L, Zhang Z, Li H, Xiong S, Ma X, Liu Y, Wang X
Plant Physiol Biochem · 2026 Jun · PMID 42150446 · Publisher ↗
Nitrogen deficiency is a major limiting factor for plant growth, yet the mechanisms underlying root growth under nitrogen-deficient conditions remain unclear. This study examined how glutamine synthetase (GS) in root tip...
Nitrogen deficiency is a major limiting factor for plant growth, yet the mechanisms underlying root growth under nitrogen-deficient conditions remain unclear. This study examined how glutamine synthetase (GS) in root tips mediates primary root elongation in wheat under nitrogen deficiency. We found that GS activity increased in root tips under nitrogen-limited conditions, promoting cell division in the meristematic zone by providing glutamine (Gln) for nucleotide biosynthesis. Metabolomic and transcriptomic analyses revealed that GS coordinated nitrogen assimilation with carbon skeletons flowing into glycolysis and the TCA cycle, ensuring a sufficient nucleotide supply for cell division. TaGS1; 1, predominantly expressed in the meristematic zone, appears to be the key isoenzyme mediating these processes. This study shows that GS in root tips supports root elongation by driving nucleotide metabolism through Gln provision under nitrogen deficiency. These findings offer new insights into nitrogen signaling in root elongation and suggest potential strategies for improving nitrogen use efficiency in crops.
Identification of key MYB transcription factors mediating MeJA-induced eupatilin accumulation by regulating AYFOMT2 expression in Artemisia argyi.
Peng S, Yang Y, Zhang Q … +6 more , Feng W, Li J, Chen M, Huang B, Liu D, Miao Y
Plant Physiol Biochem · 2026 Jun · PMID 42143888 · Publisher ↗
Methoxylated flavones in Artemisia argyi, especially eupatilin, are important bioactive components with antibacterial, anti-inflammatory, and anti-tumor activities. Exogenous treatment with methyl jasmonate (MeJA) signif...
Methoxylated flavones in Artemisia argyi, especially eupatilin, are important bioactive components with antibacterial, anti-inflammatory, and anti-tumor activities. Exogenous treatment with methyl jasmonate (MeJA) significantly promoted the contents of methoxylated flavones in A. argyi. However, the molecular regulatory mechanism underlying MeJA-induced methoxylated flavone biosynthesis remains largely unclear in A. argyi. In this study, transcriptional analysis following MeJA treatment revealed that key genes involved in the flavonoid biosynthetic pathway, including PAL, CHI, and CHS, as well as the critical flavonoid O-methyltransferase gene AYFOMT2, were significantly induced. Meanwhile, the MYB transcription factor family exhibited the most pronounced response to MeJA induction. Based on expression profiling, three key candidate genes, AYMYB13, AYMYB15, and AYMYB16, were screened and identified. To further characterize their regulatory mechanism in methoxylated flavones biosynthesis, yeast one-hybrid and dual-luciferase assays confirmed that AYMYB13, AYMYB15, and AYMYB16 directly bind to the promoter of AYFOMT2, thereby promoting the accumulation of eupatilin. Futhermore, overexpression of these three MYB transcription factors in A. argyi calli significantly increased the content of eupatilin. Our study demonstrated that AYMYB13, AYMYB15, and AYMYB16 were key regulators for activating the expression of AYFOMT2 in MeJA-induced methoxylated flavones accumulation. These findings will provide a theoretical foundation for improving eupatilin content and biosynthetic efficiency in A. argyi.
Identification and expression analysis of Trehalose-6-phosphate phosphatase (VvTPP) genes in grape and function of the VvTPPA gene in salt stress response.
Wang L, Wang J, Li R … +6 more , Qu Z, Li K, Li S, Xing H, Zhou R, Li G
Plant Physiol Biochem · 2026 Jun · PMID 42143887 · Publisher ↗
Trehalose is widely involved in the processes of plant development and in defense against stress. To date, the role of the trehalose-6-phosphate phosphatase (TPP) genes in grapevine subjected to abiotic stress remains un...
Trehalose is widely involved in the processes of plant development and in defense against stress. To date, the role of the trehalose-6-phosphate phosphatase (TPP) genes in grapevine subjected to abiotic stress remains unreported. Here, seven VvTPPs were identified in grape (Vitis vinifera), all of which contained the TPP domain. Synteny analysis revealed two gene pairs with grape and four gene pairs between grape and Arabidopsis. Phylogenetic analysis showed that VvTPPs were distributed in Class Ⅰ, Class ⅡⅠ, and Class IV. The VvTPP proteins were highly conserved in both their distribution pattern and the number of conserved motifs. The VvTPPs contained a large number of introns and exons. The VvTPP promoter sequences contained numerous cis-acting elements associated with stress and hormonal responses. Tissue-specific analysis revealed that VvTPPA was highly expressed in all grape tissues. RT-qPCR analysis indicated that seven VvTPPs were induced by at least one of the cold, drought, and salt stresses. Finally, VvTPPA overexpression enhanced salt tolerance in grape callus and Arabidopsis thaliana. Based on expression and functional analyses of VvTPPs in grape, the role of VvTPPA in salt stress response was elucidated, identifying it as a key gene for raising stress resistant grape plants in future through breeding programs.
Biochemical and structural analysis of -AtN-Myc down regulated like-1 reveals phosphatidic acid regulated esterase function.
Jaiswal A, Khatri N, Kanojia A … +4 more , Pandit S, Mishra G, Jones AM, Mudgil Y
Plant Physiol Biochem · 2026 Jun · PMID 42143886 · Publisher ↗
The N-Myc Downregulated-Like (NDL) protein family in Arabidopsis was identified as an interacting partner of components of the G-protein complex. NDL's role has been established in regulating auxin transport through modu...
The N-Myc Downregulated-Like (NDL) protein family in Arabidopsis was identified as an interacting partner of components of the G-protein complex. NDL's role has been established in regulating auxin transport through modulation of auxin transport facilitators in an Arabidopsis G-protein β subunit (AGB1)-dependent manner. NDL proteins are modulators of abiotic stress response, such as high salt and drought, and may serve as predictors of plant morphophysiological responses based on their gene expression patterns. The domain organization of NDL proteins predicts that they contain esterases/lipases with an α/β hydrolase fold. Little is known of this protein family. Biochemical analysis of Arabidopsis NDL proteins was conducted to understand the mechanism underlying their role in G protein-mediated abiotic stress-related functions and to guide hypothesis-driven experiments for long-term crop genetic improvement. To determine whether NDL1 is a lipase/esterase, we first optimized the expression of recombinant NDL1 in E. coli and tested it structurally and biochemically for lipase/esterase activity. We further analyzed NDL1's substrate-binding preference using different lipids to elucidate its mode of action in abiotic stress. We demonstrated that purified NDL1 exhibits phosphatidic acid (PA)-competitive hydrolysis of short-chain substrates, such as p-nitrophenyl acetate and p-Nitrophenyl butyrate, but not of long-chain substrates, p-Nitrophenyl laurate and p-Nitrophenyl palmitate, confirming esterase activity. We identified strong binding of NDL1 to the membrane PA and ceramide-1-phosphate, as well as weak binding towards five anionic glycerophospholipids. PA's binding and inhibition of esterase activity suggest that lipid-mediated regulation of NDL1 function is involved.
Hydrogen nanobubbles enhance the salt tolerance of Brassica chinensis L. by reshaping the growth-defense balance.
Guo X, Li X, Chen R … +3 more , Song X, Wang J, Li H
Plant Physiol Biochem · 2026 Jun · PMID 42142445 · Publisher ↗
Salinity is a key factor limiting plant growth and development. While the potential of hydrogen as a gaseous signaling molecule in enhancing crop salt tolerance has been recognized, the molecular mechanisms regulating cr...
Salinity is a key factor limiting plant growth and development. While the potential of hydrogen as a gaseous signaling molecule in enhancing crop salt tolerance has been recognized, the molecular mechanisms regulating crop growth and defense remain poorly understood. This research explores this issue via the comprehensive transcriptomic and metabolomic analysis of pakchoi (Brassica chinensis L.) under co-exposure to NaCl and hydrogen nanobubbles (HNBs). The results demonstrated that compared to the control, salt treatment significantly upregulated the synthesis and/or transduction pathways of stress hormones (ABA, JA, ET) as well as the phenylpropanoid biosynthesis pathway. This was accompanied by increased antioxidant enzyme activity and total phenolic content but also resulted in plant growth inhibition, stomatal closure, and elevated ROS content. However, compared to salt treatment, HNBs treatment partially attenuated the expression of hormone-related signaling components and reduced the content of defensive secondary metabolites (total phenolics), while further enhancing antioxidant enzyme (SOD, CAT, APX) activities and soluble sugar content. These changes were consistent with reduced ROS levels, improved stomatal aperture, and alleviated growth inhibition. These results indicate that HNBs stimulation may optimize the growth-defense balance in pakchoi under salt stress rather than sacrificing growth to adapt to the stress, which highlights the potential of HNBs in advancing sustainable agricultural practices.
Synergistic regulation by the stay-green gene family maintains green flower coloration via chlorophyll degradation in chrysanthemum.
Huang H, Wang Z, Zhang G … +9 more , Liu Y, Wen J, Zheng Y, Li M, Li D, Hong B, Gu Z, Li Y, Xu J
Plant Physiol Biochem · 2026 Jun · PMID 42142444 · Publisher ↗
Chrysanthemum is an economically important species with substantial ornamental, edible, and medicinal value. Green-flowered chrysanthemums represent a rare and highly valued phenotype among cultivated varieties; however,...
Chrysanthemum is an economically important species with substantial ornamental, edible, and medicinal value. Green-flowered chrysanthemums represent a rare and highly valued phenotype among cultivated varieties; however, the molecular mechanisms underlying green flower coloration remain poorly understood. Here, we integrated pigment quantification, transcriptome profiling, and functional validation to systematically elucidate the regulatory network governing green pigmentation. Chlorophyll content increased progressively during flower development. Transcriptomic analyses identified 11 key genes associated with chlorophyll metabolism, encompassing biosynthetic genes (GSA, HEMB, HEMY, CLH) and degradation-related genes (SGR, PPH, PAO). Notably, SGR expression was consistently downregulated throughout development. Three SGR homologs were identified in chrysanthemum-CmSGR1a, CmSGR1b, and CmSGRL-all of which localized to chloroplasts. Heterologous expression of each CmSGR in tobacco promoted chlorophyll degradation and induced leaf etiolation. In chrysanthemum, individual silencing of CmSGRL resulted in compensatory upregulation of CmSGR1a/b and accelerated chlorophyll degradation, producing lighter-colored flowers. Similarly, silencing either CmSGR1a or CmSGR1b induced upregulation of the remaining homologs and reduced chlorophyll accumulation. By contrast, simultaneous silencing of all three CmSGR genes markedly inhibited chlorophyll degradation, leading to significantly darker flowers with elevated chlorophyll levels. Collectively, these results demonstrate that CmSGR family members function redundantly and synergistically to regulate chlorophyll degradation, thereby maintaining the green flower phenotype. This study clarifies the molecular basis of green coloration in chrysanthemum and provides valuable genetic resources and theoretical support for flower color improvement.
Foliar application of exogenous gamma-aminobutyric acid alleviates the detrimental effects of combined low-temperature and low-light stress in pepper (Capsicum annuum L.).
Liang Z, Gao Y, Zhang M … +7 more , Pu K, Zhang L, Ma Y, Huo J, Zhang J, Li J, Xie J
Plant Physiol Biochem · 2026 Jun · PMID 42142443 · Publisher ↗
BACKGROUND: Combined low-temperature and low-light (LL) stress is a primary abiotic constraint limiting pepper seedlings performance in protected horticulture systems of Northwest China. Gamma-aminobutyric acid (GABA) is...
BACKGROUND: Combined low-temperature and low-light (LL) stress is a primary abiotic constraint limiting pepper seedlings performance in protected horticulture systems of Northwest China. Gamma-aminobutyric acid (GABA) is recognized as a pivotal signaling metabolite with rapid response dynamics, critically involved in modulating plant tolerance to various abiotic stresses. However, the physiological and molecular responses of pepper seedlings to exogenous GABA under LL stress conditions remain poorly understood. RESULTS: Exogenous GABA effectively alleviated LL stress in pepper seedlings grown under controlled protected cultivation conditions through coordinated physiological and molecular mechanisms. Specifically, LL stress markedly suppressed plant growth and photosynthetic efficiency, while concurrently inducing antioxidant defense systems, endogenous GABA accumulation, and the transcriptional regulation of genes associated with GABA metabolism and cold response. Exogenous GABA application-at 75 mmol L, the optimal concentration identified from a concentration gradient ranging from 0 to 125 mmol L-provided the most balanced and comprehensive mitigation of LL stress, with no observable phytotoxicity. This concentration significantly enhanced plant height, stem diameter, and biomass; increased endogenous GABA accumulation by 18.91%; and markedly alleviated leaf wilting. At the physiological level, exogenous GABA alleviated LL stress by mitigating oxidative damage-as demonstrated by reduced levels of reactive oxygen species and malondialdehyde-and by decreasing electrolyte leakage, while concurrently reducing the accumulation of protective osmolytes, specifically soluble proteins and soluble sugars. At the molecular level, exogenous GABA alleviated LL stress by modulating the expression of genes involved in the GABA shunt pathway and cold response. Specifically, it induced contrasting expression patterns: CaGABA-T2 and CaSSADH were significantly upregulated, whereas CaGAD1, CaGAD2, and CaF-BOX were markedly downregulated; in addition, the expression of CaGABA-T1, CaCBF1A, and CaCBF1B was significantly altered relative to LL-stressed controls. Principal component analysis and correlation analysis further identified coordinated relationships among exogenous GABA application, endogenous GABA accumulation, chlorophyll fluorescence parameters, fluorescence kinetic curves, and the expression of antioxidant enzyme-related genes under LL stress. CONCLUSIONS: In conclusion, under controlled protected cultivation conditions, exogenous GABA application enhances the tolerance of pepper seedlings to LL stress by promoting recovery of plant growth, regulating the antioxidant defense system, and increasing endogenous GABA accumulation.
Overexpression of ZlTTG1 increases flavonoid content, antioxidant activity, and enzyme inhibitory effects in rice seeds.
Wang L, Ma Q, Zhang B … +4 more , Cheng K, Zhang H, Zhang Z, Yan N
Plant Physiol Biochem · 2026 Jun · PMID 42142442 · Publisher ↗
The WD40 protein is a key regulator of the flavonoid biosynthetic pathway. However, its role in the flavonoid-rich aquatic cereal Chinese wild rice (Zizania latifolia) remains unclear. Here, we systematically characteris...
The WD40 protein is a key regulator of the flavonoid biosynthetic pathway. However, its role in the flavonoid-rich aquatic cereal Chinese wild rice (Zizania latifolia) remains unclear. Here, we systematically characterised the WD40 gene family in Z. latifolia. In total, 38 ZlWD40 genes were identified and mapped to 15 chromosomes. Among them, ZlTTG1 (Zla08G018110) was localised to the nucleus. ZlTTG1-overexpression (ZlTTG1) in rice changed the pericarp colour from light brown to dark purple but did not significantly affect agronomic traits. ZlTTG1 overexpression increased flavonoid content and antioxidant activity and enhanced enzyme inhibitory effects in rice seeds. Compared with the control, 155 flavonoids and 269 genes were upregulated in ZlTTG1-overexpressing rice seeds, which may contribute to the dark purple pericarp phenotype. Consistently, ZlTTG1 rice seeds showed higher expression of flavonoid biosynthetic genes (OsCHS, OsCHIL1, OsCHIL2, OsF3H-1, OsF3'H, OsDFR, OsANS, and OsUGT707A3) and increased activities of key biosynthetic enzymes, including CHS, F3H, F3'H, DFR, and ANS. This study provides a foundation for the functional analysis of ZlWD40 genes and identifies new genetic resources for developing flavonoid-rich functional rice.
Mycobiome-linked metabolomic changes reveal two cultivar-specific defense modes in field-infected date palm leaves.
Masmoudi F, Lamine M, Ben Zineb A … +9 more , Dimassi S, Mazen M, Hamdi H, Ahmed T, Al-Jabri H, Alsafran M, Mliki A, Sayadi S, Gargouri M
Plant Physiol Biochem · 2026 Jun · PMID 42142441 · Publisher ↗
Early detection of foliar fungal disease in date palm (Phoenix dactylifera L.) is essential for timely intervention, yet physiological markers preceding visible symptoms remain poorly defined. Here, we combined fungal is...
Early detection of foliar fungal disease in date palm (Phoenix dactylifera L.) is essential for timely intervention, yet physiological markers preceding visible symptoms remain poorly defined. Here, we combined fungal isolation and pathogenicity testing with untargeted GC-TOF-MS profiling of symptomatic (S) and asymptomatic (AS) leaves from four cultivars (Medjool, Sukkari, Khalas, and Khenaizi) under natural field infection. Among 103 fungal isolates, 15 were confirmed as pathogenic in detached-leaf assays, with Alternaria spp. predominating. Notably, several species, including Alternaria prunicola, Curvularia beasleyi, and Bipolaris sorokiniana, are reported here for the first time in association with date palm pathology. Metabolomic analysis revealed two cultivar-dependent response modes. Mode A, dominant in Medjool and Sukkari, was characterized by sugar reallocation, including broad hexose depletion, notably α-DL-glucopyranoside, together with an early decline in malonic acid, consistent with increased glycolytic and pentose phosphate pathway demand for defense and redox buffering. Mode B, dominant in Khalas and Khenaizi, reflected lipid-antioxidant remodeling, with increases in α-tocopherol and β-sitosterol and selective terpenoid rewiring, consistent with membrane stabilization and oxidative-stress control. PCA separated S from AS samples, while PLS-DA resolved classes with significant permutation support; VIP rankings converged with large standardized effects (Hedges' g) on a concise set of discriminant metabolites. These results establish a cultivar-resolved, field-realistic framework linking pathogen context to two distinct metabolic defense trajectories in date palms. This study identifies a list of candidate biomarkers for early fungal disease detection and provides a physiological basis for trait-aware monitoring and management of date palms under arid agricultural conditions.
Development of a hairy root transformation platform for enhanced cyclopeptide production and gene function analysis in Pseudostellaria heterophylla.
Yang Y, Shu G, Lu M … +4 more , He H, Yang C, Li P, Zhou T
Plant Physiol Biochem · 2026 Jun · PMID 42139969 · Publisher ↗
Pseudostellaria heterophylla (Miq.) Pax ex Pax et Hoffm. is a widely used traditional Chinese medicinal herb in which cyclopeptides are the major bioactive constituents. However, naturally low cyclopeptide contents and a...
Pseudostellaria heterophylla (Miq.) Pax ex Pax et Hoffm. is a widely used traditional Chinese medicinal herb in which cyclopeptides are the major bioactive constituents. However, naturally low cyclopeptide contents and a lack of an efficient genetic transformation system have hindered functional characterization of cyclopeptide biosynthetic genes. We establish a rapid and efficient Agrobacterium rhizogenes-mediated hairy root induction and transformation system for P. heterophylla. By combining in vitro embryo culture to overcome seed dormancy using a filter paper sandwich co-cultivation method, we achieve a hairy root induction rate of 73.43% at 18 d, and a transformation efficiency of 48.94% using A. rhizogenes strain K599. The system is validated by stable expression of DsRed2 and RUBY reporter genes. Metabolite profiling reveals hairy roots accumulate significantly higher levels of heterophyllins A and B, but lower levels of polysaccharides and saponins compared with normal roots, indicating selective activation of cyclopeptide biosynthesis. We also clone and functionally characterize the precursor gene PhPreHA-the overexpression of which in hairy roots leads to a marked increase in heterophyllin A accumulation. This study pioneers a hairy root-based genetic transformation system in P. heterophylla and provides the first functional validation of a cyclopeptide precursor gene. In doing so, it offers a robust platform for pathway dissection and metabolic engineering of medicinal plants.
PeMPK7 enhances poplar salt tolerance by coordinating phytohormone dynamics and activating an ethylene-ERF114 regulatory module.
Li B, Gao X, Wei G … +5 more , Li J, Wang D, Zhao Y, Zhang S, Guo J
Plant Physiol Biochem · 2026 Jun · PMID 42139968 · Publisher ↗
Salt stress constrains poplar growth. The mitogen-activated protein kinase (MAPK) cascade and phytohormones are key regulators of plant salt tolerance. However, the mechanisms by which MAPK cascades orchestrate hormone h...
Salt stress constrains poplar growth. The mitogen-activated protein kinase (MAPK) cascade and phytohormones are key regulators of plant salt tolerance. However, the mechanisms by which MAPK cascades orchestrate hormone homeostasis under salt stress in poplar are still poorly understood. This study shows that overexpressing PeMPK7 improved poplar salt tolerance. After 12 h of NaCl treatment, salicylic acid and abscisic acid (ABA) contents in PeMPK7-overexpressing poplars were significantly higher than in wild-type plants (P < 0.05). Transcriptomic profiling revealed that PeMPK7 reprogrammed phytohormone metabolism and signaling pathways, notably up-regulating ethylene (ET) biosynthesis genes (ACS1, ACO1) together with genes associated with indole-3-acetic acid, cytokinin, ABA, gibberellic acid, and jasmonic acid. Weighted gene co-expression network analysis suggested that PeMPK7 may act upstream of NAC072, NAC002, and TGA7, which are associated with ABA metabolism and signaling under salt stress. Among differentially expressed transcription factor genes, PagERF114 expression was induced by salt in PeMPK7-overexpressing plants and could be boosted by exogenous ET. Transgenic poplars overexpressing PagERF114 displayed enhanced salt tolerance, lower MDA content, and higher SOD/POD activities, demonstrating that PagERF114 enhances salt tolerance. Taken together, our findings suggest that PeMPK7 fine-tunes phytohormone homeostasis and partially enhances salt tolerance through an ethylene-associated pathway involving PagERF114.
Garlic-released NO and HS modulate Arabidopsis metabolism by reshaping redox balance and redox-dependent post-translational modifications.
Corpas FJ, González-Gordo S, Muñoz-Vargas MA … +4 more , Rodríguez-Ruiz M, Ruiz-Torres C, Taboada J, Palma JM
Plant Physiol Biochem · 2026 Jun · PMID 42127715 · Publisher ↗
Nitric oxide (NO) and hydrogen sulfide (HS) are key gasotransmitters acting as signaling molecules in plants and animals. Garlic, known for its sulfur-rich compounds, had not previously been identified as a source of NO...
Nitric oxide (NO) and hydrogen sulfide (HS) are key gasotransmitters acting as signaling molecules in plants and animals. Garlic, known for its sulfur-rich compounds, had not previously been identified as a source of NO or HS emission. Using specific sensors, we show that garlic cloves simultaneously release both gases. To assess their biological impact, 30-day-old Arabidopsis thaliana plants were exposed for 24 h to a garlic-released NO/HS-enriched atmosphere. Biochemical analyses revealed significant changes in components of reactive oxygen species (ROS), NO, and HS metabolism, including protein S-glutathionylation, S-nitrosation and tyrosine/tryptophan nitration. Major effects were detected in the antioxidant enzyme catalase (CAT), the HO-producing glycolate oxidase (GOX), and hydroxypyruvate reductase (HPR), all central to peroxisomal redox metabolism. The activity of the HS-producing enzyme L-cysteine desulfhydrase (LCD) and the expression of PAO4, encoding a peroxisomal HO-generating polyamine oxidase, were also modified. Conversely, nitrite/NADH-dependent NO generation and nitrosoglutathione reductase (GSNOR) activity remained unchanged. These results collectively indicate that garlic-released NO and HS modulate the metabolism of A. thaliana through redox-dependent post-translational modifications, thereby promoting adaptive redox responses. This suggests that garlic may act as a natural dual donor of both NO and HS.
Nano-biochar regulates soil enzymatic activities and nitric oxide signaling to improve photosynthesis and nutrient balance in Brassica napus under salt stress: Implications for precision agriculture.
Esgici R, Eliçin AK, Albalawi T … +3 more , Azzam MA, Faizan M, Alam P
Plant Physiol Biochem · 2026 Jun · PMID 42127714 · Publisher ↗
Salinity stress is a critical abiotic constraint that impairs crop productivity across both irrigated and rainfed agroecosystems. In recent years, nanotechnology has gained considerable attention in agriculture due to it...
Salinity stress is a critical abiotic constraint that impairs crop productivity across both irrigated and rainfed agroecosystems. In recent years, nanotechnology has gained considerable attention in agriculture due to its potential to enhance plant tolerance to abiotic stresses. Although nano-biochar (nano-BC) has been widely investigated for improving soil fertility, limited information is available regarding its effects on Brassica napus L. (rapeseed) under salinity stress. The present study evaluated the impact of nano-BC on rapeseed growth, photosynthetic performance, antioxidant defense, osmolyte accumulation, soil enzymatic activities, and soil physicochemical properties under saline conditions. At the flowering stage, plants were treated with two levels of nano-BC (75 g and 150 g plant). Salinity stress markedly impaired plant performance, as indicated by a 53% increase in hydrogen peroxide (HO) and a 68% increase in malondialdehyde (MDA), reflecting enhanced oxidative damage and lipid peroxidation. Application of nano-BC significantly mitigated these adverse effects by enhancing antioxidant enzyme activities, including superoxide dismutase (SOD) (71%), peroxidase (POX) (69%), and catalase (CAT) (81%), along with improved flavonoids (16% and 21%), anthocyanins (23% and 31%), and protein content (14% and 19%) respectively over their controls. Moreover, nano-BC application substantially increased soil enzymatic activities and improved key soil physicochemical properties, thereby enhancing nutrient availability and overall soil fertility. Overall, the findings demonstrate that nano-BC effectively alleviates salinity-induced stress by improving plant physiological performance, strengthening antioxidant defense systems, promoting osmoprotectants accumulation, and enhancing soil health. These findings underscore the potential of nano-BC as an effective and sustainable approach for enhancing rapeseed productivity under saline conditions.
Functional characterization and key residue analysis of oxidosqualene cyclases involved in amyrin and cycloartenol formation in Parashorea chinensis.
Ding J, Wang X, Li H … +9 more , Xiang G, Yuan S, Zhang Y, Deng X, Yang Z, Hao B, Yang S, Li X, Zhang G
Plant Physiol Biochem · 2026 May · PMID 42127659 · Publisher ↗
Dipterocarpaceae dammar resins contain diverse triterpenoids, including dammarane constituents and scaffolds other than dammarane, such as derivatives with oleanane, ursane or lupane scaffolds, but the oxidosqualene cycl...
Dipterocarpaceae dammar resins contain diverse triterpenoids, including dammarane constituents and scaffolds other than dammarane, such as derivatives with oleanane, ursane or lupane scaffolds, but the oxidosqualene cyclases (OSCs) underlying this scaffold diversity remain poorly characterized. OSCs catalyze the cyclization of 2,3-oxidosqualene to generate distinct triterpene scaffolds. Genome mining identified 13 putative PcOSC genes in Parashorea chinensis. Guided by triterpenoid scaffold information from accessible leaf and stem tissues and by phylogenetic placement, we prioritized a PcOSC clade related to amyrin formation and a branch related to cycloartenol and sterol biosynthesis for functional analysis. Yeast expression assigned PcOSC10 as a cycloartenol synthase, PcOSC4 as a β-amyrin synthase, and PcOSC3 as a multifunctional α/β-amyrin synthase. Transient expression in Nicotiana benthamiana provided complementary evidence from a plant host for PcOSC3 and PcOSC4, whereas the cycloartenol signal associated with PcOSC10 expression was interpreted relative to the matched control because cycloartenol is an endogenous sterol intermediate in plant tissues. Key residue analysis identified residues associated with scaffold outcome and product output. PcOSC3 M729N shifted products from amyrins to lupeol, PcOSC4 K729N enabled germanicol formation, and PcOSC4 L483I increased β-amyrin output by approximately 4.3-fold under the tested yeast expression conditions. Together, these data define representative PcOSCs involved in amyrin formation and in the cycloartenol/sterol-related branch and identify residues associated with OSC scaffold choice and product output. Although the branch responsible for dammarane formation remains to be resolved by separate functional characterization, the present study provides an initial framework guided by metabolite information and phylogenetic analysis for dissecting triterpenoid scaffold diversification controlled by OSCs in Dipterocarpaceae.
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