Search Results (309)

Fruit production represents a major agricultural sector worldwide; however, it is severely affected by pests that reduce fruit yield, quality, and marketability. The intensive use of chemical insecticides has generated environmental contamination, resistance in pest populations, and risks to human health, increasing the demand for sustainable alternatives. In this context, endophytic fungi (EF) have gained relevance as biological control agents due to their ability to colonize plant tissues and produce bioactive metabolites that affect agricultural pests. This systematic review aimed to evaluate the current scientific knowledge regarding EF as biological control agents against pests in fruit crops and to analyze the tripartite interactions among fungi, plants, and pests. The review was conducted following PRISMA guidelines using the databases Web of Science, Scopus, PubMed, and OpenAlex. Studies were selected according to predefined exclusion criteria focused on the simultaneous presence of endophytic fungi, fruit crops, and agricultural pests. A total of 24 fruit species, 51 endophytic fungi, and 33 agricultural pest species were identified. The most frequently reported fungal genera were Penicillium, Cladosporium, Fusarium, Aspergillus, Gnomoniopsis, and Trichoderma, while a broad diversity of pest species affected by these fungi was recorded. Interaction analyses revealed complex and highly interconnected tripartite relationships, in which some fungi exhibited strong host specificity whereas others displayed broader interaction ranges. The findings demonstrate that EF possess significant potential as sustainable biological control agents in fruit production systems. However, research in this field remains limited and fragmented, highlighting the need to develop standardized models, validate their efficacy under field conditions, and conduct studies focused on the commercial scalability of EF-based management strategies. Full article

Rumen biohydrogenation is a microbial process that converts dietary unsaturated fatty acids into more saturated products and produces a range of intermediates that can affect animal products and rumen fermentation. This review summarizes current knowledge on the main biohydrogenation pathways, the microbial groups involved, and the nutritional and breeding strategies used to regulate this process. Particular attention is given to the transformation of C18 fatty acids, the formation of vaccenic acid and conjugated linoleic acid, the trans-10 shift, and the links between lipid metabolism, hydrogen use, and methane formation. Evidence indicates that diet composition, lipid source, plant secondary metabolites, rumen-protected fat technologies, microbial interventions, and host-related factors can all influence biohydrogenation outcomes. These strategies can improve the fatty acid profile of meat and milk, but their effects are context-dependent and vary with animal species, diet, and rumen microbial structure. Important gaps remain, including the identification of active microbial populations, the functions of many transient intermediates, and the extent to which changes in biohydrogenation directly contribute to methane mitigation. Clarifying these mechanisms is essential for improving the nutritional quality of ruminant products and the sustainability of production systems. Full article

Taxilli Herba (Sangjisheng) is a hemi-parasitic medicinal plant whose quality is intrinsically linked to its host species. While previous reviews have extensively summarized its chemical constituents and pharmacological activities, a systematic understanding of how host trees dictate its quality and safety remains largely fragmented. This review bridges this gap by proposing a “host-governed quality paradigm.” By integrating historical records with modern scientific findings, we critically evaluate the molecular mechanisms underlying host–parasite interactions and their impact on medicinal quality. We highlight that host species influence Taxilli Herba across three critical dimensions: (i) chemical composition, comprising both intrinsic bioactive compounds and host-derived metabolites; (ii) toxicity profile, where even hosts lacking cardiac glycosides may pose potential safety hazards; and (iii) pharmacological activity, where host identity modulates therapeutic potency and traditional medicinal properties (e.g., “cold” vs. “warm” nature). Importantly, we highlight that the cardiac glycoside test specified in the current Chinese Pharmacopoeia is insufficient to ensure the safety of Sangjisheng derived from diverse hosts. To address these challenges, we propose a host-governed quality paradigm comprising four pillars: (1) mechanistic studies on host–parasite interactions; (2) revision of pharmacopeial standards to restrict approved sources; (3) promotion of standardized cultivation using safe host species (e.g., Morus alba); and (4) stringent quality control for edible and medicinal applications. This framework aims to ensure the safety, efficacy, and sustainable use of Sangjisheng in clinical practice. Full article

Medicinal plants are important sources of secondary metabolites (SMs), but their production is constrained by resource shortages, low cultivation efficiency, and continuous cropping obstacles. As the “second genome” of host plants, the plant microbiome is deeply involved in plant growth and development, stress adaptation, and the accumulation of bioactive compounds, providing new pathways for the sustainable utilization of traditional Chinese medicine resources. This review summarizes the mechanisms by which the plant microbiome regulates biomass formation and SM accumulation in medicinal plants. Microorganisms can promote plant nutrient acquisition, enhance resistance to biotic and abiotic stresses, and regulate root architecture and hormonal signaling. Meanwhile, microorganisms can also participate in the remodeling of secondary metabolic networks in medicinal plants through elicitor- and effector protein-mediated signal transduction, regulation of metabolic gene expression, redistribution of photosynthetic carbon sources and metabolic precursors, and their own biosynthetic capacities. From the perspective of co-evolution, plants and their microbiomes constitute symbiotic systems formed through long-term interactions. Plants can selectively recruit specific microbial taxa through root exudates, SMs, and signaling molecules, whereas microorganisms influence plant adaptability and medicinal material quality through colonization, metabolic feedback, and horizontal gene transfer. This review proposes that a synergistic regulatory pattern of “close phylogenetic relatedness-similar secretions-similar microbial communities” may exist between medicinal plants and microorganisms. This pattern suggests that closely related medicinal plants may share similar core microbial taxa, which may help reveal the intrinsic mechanisms underlying specific microbial recruitment and the quality formation of geo-authentic medicinal materials. Furthermore, the design of synthetic microbial communities (SynComs) can be achieved based on the identification of shared functional genes and the screening of indigenous core functional strains. Full article

Plant-pathogenic bacteria threaten crop productivity and quality, yet chemical options remain limited compared with those for fungal and oomycete diseases. Current management relies mainly on copper bactericides, limited antibiotics, induced-resistance agents, biocontrol and resistant cultivars. However, copper and streptomycin resistance, efflux-mediated multidrug tolerance and rapid pathogen adaptation have weakened these strategies. Target-oriented research provides a framework for exploring agricultural antibacterials, anti-virulence agents, anti-colonization strategies, resistance sensitizers and host-resistance interventions, but many of these approaches remain conceptual, model-system, greenhouse or medical-bacteriology-derived rather than proven field solutions. This review classifies bacterial control targets into two interconnected groups: growth-essential targets, including peptidoglycan biosynthesis, membrane/envelope systems, nucleic-acid processes, protein synthesis, metabolism, nutrient transport and cell division; and anti-virulence/anti-adaptation targets, including secretion systems, quorum sensing, biofilms, motility, adhesion, cell-wall-degrading enzymes, tolerance systems, oxidative-stress responses and host susceptibility factors. Using “Candidatus Liberibacter asiaticus” (CLas) as a case study, genome annotation and infection-stage transcript-abundance data prioritized Sec-dependent secretion, outer-membrane/surface proteins, Bam assembly, nutrient transporters, Clp proteostasis, redox adaptation and core cellular processes as candidate target classes. Envelope-associated, secretion/anti-virulence, nutrient-acquisition and stress-sensitization modules may represent potential directions for downstream validation, but CLas candidates remain hypothesis-generating priorities requiring validation for essentiality, conservation, druggability, delivery feasibility, crop safety and field performance. Full article

Postbiotics are defined as preparations of inanimate microorganisms and/or their components that confer a health benefit on the host. Although interest in postbiotics has increased substantially, their translational use in functional foods remains insufficiently characterized with respect to preparation identity, production methodology, food-matrix compatibility, mechanistic specificity, and regulatory positioning. This PRISMA-guided structured review aims to synthesize current evidence on postbiotics in functional food and nutraceutical contexts, with particular emphasis on preparation-based characterization, gut–brain axis-related mechanisms and clinical findings, food matrix applicability, and regulatory and health-claim considerations. Unlike broader postbiotic reviews that mainly address definitions, general health effects, or technological stability, this review integrates preparation identity, production process, gut–brain axis-related evidence, food matrix compatibility, and regulatory/health-claim translation within a single functional food framework. A structured literature search was conducted in Scopus and Web of Science Core Collection and was completed on 16 February 2026. The search strategy included three conceptual blocks: postbiotic and inactivation-based preparation terms, functional food/nutraceutical and food matrix terms, and gut–brain axis-related clinical and mechanistic terms. Cosmetic, topical, veterinary, animal feed, and aquaculture-focused publications were excluded. The export files contained 131 records from Scopus and 136 from the Web of Science Core Collection, yielding 267 records after applying document-type and language filters. After manually removing duplicates, 237 unique records were screened. Following title/abstract screening, 176 records were excluded as outside the scope of the review, and 61 publications were retained for full-text assessment and final thematic synthesis. The review was reported according to applicable PRISMA 2020 items. The evidence was organized into three thematic domains: gut–brain axis-related clinical findings, mechanistic evidence, and food matrix/product development applications. Heat-inactivated preparations, including Lactobacillus gasseri CP2305 and Lactiplantibacillus plantarum SNK12, have shown preliminary effects on stress-related symptoms, sleep quality, and selected neuroendocrine or inflammatory biomarkers in human studies. Mechanistic pathways include gut barrier integrity, immunomodulation, short-chain fatty acid signaling, tryptophan–kynurenine–serotonin metabolism, vagal communication, and regulation of the hypothalamic–pituitary–adrenal axis. Food matrix studies support the potential application of postbiotics in fermented dairy products, cereal-based systems, plant-based matrices, powders, concentrates, and bioactive packaging; however, matrix-dependent effects on bioavailability, sensory quality, and biological activity remain incompletely defined. Postbiotics provide a stable translational platform for functional-food development, but their scientific and commercial use requires clear characterization of the microbial source, production process, inactivation method, retained active fractions, dose metric, delivery matrix, and clinically meaningful endpoint. Future studies should avoid broad category-level claims and prioritize preparation- and matrix-defined human evidence with standardized safety reporting. Full article

Huanglongbing (HLB), caused by Candidatus Liberibacter asiaticus (CLas) and vectored by Asian citrus psyllid (Diaphorina citri), remains a major constraint to sustainable citrus production. In Florida, individual protective covers (IPCs) have been adopted as an effective psyllid exclusion tool by shielding young trees from this vector of the phloem-dwelling bacterium CLas. Brassinosteroids (BRs), a class of plant steroid hormones, are being explored as a treatment to mitigate HLB and are approved for commercial use in the state. We investigated the effect of IPCs combined with homobrassinolide (HBr) applied as a foliar spray on CLas titer, canopy volume, tree growth, yield, fruit quality, and defense-related gene expression of the salicylic acid (SA) pathways in ‘Tango’ mandarin grafted on sour orange (SO) or US-942 rootstocks. After being covered with IPCs in the field for three years, trees were subjected to monthly foliar application of HBr upon IPC removal. The experiment included four treatment groups: trees with IPC and HBr spray (IPC HBr+), IPC without HBr (IPC HBr-), no-IPC with HBr (no-IPC HBr+), and no-IPC without HBr (no-IPC HBr-). IPCs effectively delayed bacterial infection for six to nine months after IPC removal, maintaining higher cycle threshold (Ct) values (lower CLas titers) than in no-IPC trees, confirming the protective effect of IPCs against early CLas colonization. The combination of IPCs and HBr spray significantly enhanced canopy volume, particularly in trees grafted on SO. This effect was sustained over one year and was consistently greater in IPC HBr+ trees than in IPC HBr- and no-IPC HBr+ or HBr- trees, suggesting a synergistic effect of the combined therapy on enhancing tree growth. The tree height and trunk diameter were primarily improved by IPC, regardless of HBr treatment. IPC-treated trees exhibited significantly greater height and trunk diameters (scion and rootstock) than no-IPC trees across one or both rootstocks, indicating that IPCs alone contribute to these horticultural growth improvements. IPC trees also showed reduced preharvest fruit drop compared to the no-IPCs trees, resulting in higher yields, with additional gains observed in IPC HBr+ trees on SO. Fruit quality attributes, including °Brix, titratable acidity, peel color, and size, did not differ significantly among treatments. Importantly, gene expression analysis revealed early and sustained upregulation of key SA pathway genes in IPC HBr+ trees, indicating that HBr effectively activated systemic acquired resistance (SAR), particularly on SO rootstock. This study highlights the complementary roles of IPCs and HBr in the management of HLB. While IPCs provided essential early protection against CLas and promoted long-term horticultural growth, HBr enhanced early canopy development, activated host defense mechanisms, and enhanced yield. The integration of both approaches offers a sustainable and effective strategy to protect young citrus trees, delay CLas infection, and improve tree health and productivity under endemic HLB. Full article

Fungal communities associated with the phyllosphere can influence plant health, stress responses, and disease dynamics in managed crop systems. However, limited information is available on fungal microbiome structure across phyllosphere compartments of Eucalyptus cinerea cultivated for cut foliage production. In this study, fungal communities (including epiphytic and endophytic fungi) associated with leaf, stem, and bark tissues of intensively managed E. cinerea grown in Ireland were characterised using ITS amplicon sequencing. Samples were collected from five trees, with tissues pooled by compartment to generate 15 biological samples. Following quality control and denoising, 405 fungal amplicon sequence variants (ASVs) were retained for analysis. Observed richness, Shannon and Simpson indices, and Faith’s phylogenetic diversity differed among compartments, with bark exhibiting higher values than leaf and stem tissues (p < 0.05). PERMANOVA analysis indicated that both compartment (R² = 0.239, p = 0.002) and tree identity (R² = 0.451, p = 0.002) significantly influenced fungal community composition. Bark communities were dominated by Diaporthe (52.9%), Peniophora (12.8%), and Talaromyces (10.4%), whereas leaf and stem communities were characterised primarily by Vishniacozyma and Sporobolomyces. Differential abundance analysis identified 26 and 23 differentially abundant ASVs between bark and leaf, and bark and stem tissues, respectively, whereas no significant differences were detected between leaf and stem communities. Weighted UniFrac analyses further revealed separation of bark-associated communities from photosynthetic tissues. These findings demonstrate compartment-associated variation in fungal community structure within the phyllosphere of managed E. cinerea and highlight the importance of considering both host-level and tissue-level effects in plant microbiome studies. This study provides a baseline assessment of fungal assemblages associated with commercially managed Eucalyptus under Irish growing conditions and supports future investigations into the functional significance of these microbial communities for plant health and resilience. Full article

Ilyonectria is a common soil-inhabiting fungal genus that comprises numerous plant phytopathogenic species capable of infecting a wide array of crops, medicinal herbs, and horticultural plants. However, the lack of a reliable and efficient genetic transformation method has severely hindered the elucidation of the pathogenic mechanisms of Ilyonectria pathogens. In this study, we established an efficient protoplast-mediated genetic transformation method for two dominant Panax root rot pathogens, I. robusta and I. vredehoekensis. Key parameters governing high-quality protoplast preparation, including mycelium culture time, enzyme composition, osmotic stabilizer type, digestion speed, and digestion time, were systematically optimized. Subsequently, orthogonal experiments were conducted to optimize the PEG-CaCl₂-mediated transformation conditions and to screen regeneration media for protoplasts. The optimal enzymatic system is composed of 20 mg/mL driselase and 10 mg/mL lysing enzyme, with 0.7 M NaCl as the osmotic stabilizer. Under these conditions, high-viability and high-quality protoplasts were obtained from I. vredehoekensis after 3 h of digestion at 150 rpm, and from I. robusta after 2 h of digestion at 100 rpm, yielding 5.52 × 10⁷ CFU/mL and 5.75 × 10⁷ CFU/mL protoplasts, respectively. Efficient transformation was achieved using a mannitol-prepared STC buffer mediated by 40% PEG4000. PCR and fluorescence microscopy verified positive transformants. Additionally, pathogenicity assays showed no significant differences in virulence between the transformed and wild-type strains, suggesting that the transformation procedure did not alter virulence. To the best of our knowledge, this is the first study to successfully establish genetic transformation methods for I. robusta and I. vredehoekensis, providing an essential technical platform for functional gene analysis, pathogenicity studies, and host–pathogen interaction research. In addition, the optimized transformation strategy may serve as a valuable reference for studies on other Ilyonectria species. Full article

Background: Pectobacterium brasiliense-mediated soft rot severely threatens the production of diverse cash crops worldwide and brings severe yield reduction risks. A virulent strain BS1113 was separated from diseased cigar tobacco plants collected in Yunnan, yet its virulence regulatory genes and copper resistance-related genetic background have not been fully analyzed so far. This study aims to decipher the genomic features of BS1113 and clarify its pathogenic and copper-tolerant characteristics via whole-genome sequencing, comparative genomics and indoor phenotype verification. Methods: Hybrid sequencing strategies combining Illumina short reads and PacBio long reads were adopted to obtain the complete circular genome sequence of strain BS1113. Subsequent comparative genomic analysis and multiple phenotypic identification experiments were conducted to characterize its genetic architecture and physiological traits. Results: Genome assembly results showed that the circular chromosome of BS1113 spans 4,916,962 bp with a GC content of 51.96%, which encodes a total of 4369 functional protein-coding genes. Genomic comparison revealed that BS1113 completely lacks the T3SS gene cluster, while it conserves intact T2SS, T6SS and I-F CRISPR-Cas systems; the chromosomal copper resistance operon copRSAB was also detected in this isolate. Pathogenicity tests validated that BS1113 satisfies all criteria of Koch’s postulates on cigar tobacco hosts. In addition, BS1113 displayed prominent tolerance against eight mainstream copper bactericides widely used for tobacco disease management. Conclusions: This research generates the first complete high-quality genome of P. brasiliense isolated from cigar tobacco hosts. The genomic data explain the infection mechanism of this pathogen independent of intact T3SS, and also reveal the genetic basis supporting its persistent survival under long-term copper fungicide pressure in field cultivation environments. Full article

Background/Objectives: This study aims to establish a systematic phytochemical characterization and quality evaluation method to systematically evaluate the influence of multiple factors on the chemical composition of Taxillus chinensis, thereby providing a scientific basis for its development, utilization, and quality control standards. Methods: To ensure a targeted and representative metabolic screening, six representative batches covering the major geographical origins and host plants were selected for initial metabolomic profiling. An integrated analytical approach combining UPLC-MS/MS-based widely targeted metabolomics, HPLC fingerprinting, and multi-component quantitative analysis with multivariate statistical analysis was employed. Results: Significant quality variations were identified across the samples. Metabolomics results indicated that while chemical component types were qualitatively consistent across growth conditions, their contents varied significantly. Unique differential metabolites clustered according to specific geographical origins or host plants. KEGG pathway analysis revealed that geographical origin primarily regulated phenylpropanoid biosynthesis, whereas host differences mainly influenced flavonoid and monoterpenoid biosynthesis. Furthermore, HPLC fingerprinting of 20 batches demonstrated similarities greater than 0.9, with 15 common peaks determined. Based on their high relative abundance, differential significance across samples, and documented pharmacological relevance to the herb’s traditional efficacy, six bioactive components—gallic acid, catechin, epicatechin, hyperoside, isoquercitrin, and quercitrin—were identified and quantified. Notably, samples originating from Wuzhou exhibited the highest total content of these components. Consistent with PCA and HCA results, gallic acid, hyperoside, isoquercitrin, and quercitrin were identified as potential markers driving quality differences. Conclusions: This integrated approach allows for a systematic analytical screening of Taxillus chinensis, clarifying chemical variations caused by environmental and biological factors, and supporting the standardization and comprehensive utilization of this medicinal plant. Full article

Plants can provide natural enemies with alternative food resources that enhance their performance in addition to prey consumption. Extrafloral nectaries attract beneficial insects by supplying nectar in exchange for pest suppression, although other arthropods may also benefit. This study aimed to characterize the extrafloral nectar composition of bottle gourd, Lagenaria siceraria (Molina) Standley (Cucurbitaceae), a host plant of Nesidiocoris tenuis Reuter (Hemiptera: Miridae), and to evaluate the effects of its carbohydrate profile on key biological parameters of this predator. Extrafloral nectar was chemically characterized for carbohydrate and amino acid composition, and laboratory bioassays were conducted to assess the effects of a sugar solution of the extrafloral nectar carbohydrate profile when provided with two factitious food sources, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) eggs and Artemia sp. (Anostraca: Artemiidae) cysts. Female egg production, nymphal development and food source consumption were evaluated. Chemical analysis revealed that bottle gourd extrafloral nectar consisted primarily of glucose, fructose, sucrose and melezitose, while serine was the dominant amino acid. Four essential amino acids were also detected. Sugar supplementation did not affect nymphal development rate but significantly reduced factitious food consumption. Significant differences in egg production were observed among feeding regimes. Sugar supplementation did not affect egg production when E. kuehniella eggs were provided, but significantly increased egg production when Artemia cysts were used as food source. These results indicate that extrafloral nectar carbohydrates can function as effective supplementary nutritional resources for N. tenuis, particularly when lower-quality factitious food sources are used. These findings enhance our understanding of plant–predator nutritional interactions and suggest that extrafloral nectar-derived components warrant further evaluation for incorporation into mass rearing protocols. Full article

Phytophthora blight, caused by the oomycete pathogen Phytophthora capsici, is a devastating disease that severely constrains pepper (Capsicum annuum) production, leading to significant yield reduction and quality deterioration. Pathogen infection elicits a host immune response that involves extensive transcriptional reprogramming, during which transcription factors (TFs) act as key regulatory hubs linking upstream signaling cascades to downstream defense gene expression networks. NAC TFs represent a plant-specific gene family and play crucial roles in plant growth, development, and response to various stresses. However, the infection-responsive transcriptional dynamics and functions of NAC TFs during pepper–P. capsici interactions remain poorly elucidated. In this study, transcriptome profiling and RT-qPCR analysis of pepper plants challenged with P. capsici identified three NAC TF genes—CaNAC61, CaNAC79, and CaNAC92—that were consistently upregulated at the infection stages. Subcellular localization assays demonstrated that all these three proteins localize to the nucleus. Silencing of CaNAC61, CaNAC79, or CaNAC92 in pepper conferred enhanced resistance to P. capsici. In contrast, their transient overexpression in pepper leaves significantly promoted lesion expansion and suppressed transcript levels of the defense marker genes CaPR1, CaDEF1, and CaLOX1. Consistently, heterologous overexpression in transgenic Nicotiana benthamiana further validated CaNAC61, CaNAC79, and CaNAC92 as negative regulators in resistance to P. capsici. Collectively, our findings demonstrated that CaNAC61, CaNAC79, and CaNAC92 negatively regulate plant resistance to P. capsici, expanding the functional diversity of NAC TFs in plant immune responses and providing valuable candidate targets for genetic improvement against Phytophthora blight. Full article

Introduction: The upper Arlanza River (Duero Basin, Burgos, Spain) hosts a genetically distinct local lineage of brown trout (Salmo trutta fario), the “Arlanza strain”, largely free from hatchery-derived introgression, alongside other native cyprinids of conservation concern, including the Iberian chub (Achondrostoma arcasii, Vulnerable—IUCN). The river also supports the Iberian desman (Galemys pyrenaicus, Endangered—IUCN) and Eurasian otter (Lutra lutra). Despite these values, the study reach presents multiple transverse obstacles limiting longitudinal connectivity and degraded riparian cover in critical sections due to livestock erosion, compromising habitat quality for all species. Objective: This study aimed to design engineering interventions to improve fluvial and riparian habitat in a 4 km reach of the upper Arlanza River, restoring longitudinal connectivity and thermal refuge availability while strictly preserving the genetic integrity of the native Arlanza trout strain. Methodology: The reach was characterised through electrofishing surveys, riparian quality assessment (modified RQI index), hydraulic refuge evaluation (IR index), and hydrological analysis based on a 30-year flow record. Brown trout population dynamics were modelled using dimP 1.0 software, with a comparative analysis between upstream (Quintanar de la Sierra village) and downstream (Vilviestre del Pinar village) sampling points to identify connectivity bottlenecks. Engineering works were scheduled to avoid reproductive periods of all target species. Results: The upstream population showed a rejuvenated age structure (density: ~1.40 ind/m; mean length: 12.0 cm), consistent with good spawning conditions but limited growth capacity due to cold temperatures and low summer flows. The downstream point exhibited a severely reduced population (~0.10 ind/m), indicating marked loss of connectivity and habitat degradation. Priority intervention zones were identified in the Camping and lower Prado Mayor sub-reaches. Proposed measures included weir notching to restore fish passage, livestock watering points to reduce bank erosion, and riparian restoration by planting native species (Populus tremula, Betula alba, Salix spp.) protected with fences. Conclusions: Restoring longitudinal connectivity and riparian cover in the upper Arlanza River are essential to protect the genetically valuable Arlanza trout strain, the endangered G. pyrenaicus, and other native fish species, providing a transferable framework for headwater fluvial restoration that jointly addresses biodiversity conservation and genetic resource protection. Full article

SND (Secondary wall-associated NAC domain) transcription factors are core regulators of secondary cell wall formation in plants. To identify key genes involved in wood formation in Pinus massoniana Lamb. and elucidate the molecular regulatory mechanisms underlying its wood formation, this study systematically characterized the SND gene family in P. massoniana and performed functional validation of the candidate gene PmSND4. Candidate sequences were obtained by screening the transcriptome database, and SND family members were identified by combining Pfam domain validation. Bioinformatics analysis was used to analyze their phylogenetic relationships and conserved motif characteristics. Tissue expression profiling was employed to screen potential candidate genes, and the molecular characteristics of PmSND4 were analyzed through subcellular localization. Poplar was used as a heterologous expression host to validate its biological function. The results showed that six P. massoniana SND family members (PmSND1-6) with complete NAC domains were identified. PmSND4 belongs to the SND/ANAC075 subfamily, and is preferentially expressed in stems, with relatively lower and comparable expression levels in needles and roots. It is localized in the nucleus. Overexpression of PmSND4 significantly promoted the vegetative growth of transgenic poplar, increased stem xylem cell wall thickness, and significantly enhanced lignin and hemicellulose contents, but had no significant effect on cellulose content. This study completed the systematic identification of the SND gene family in P. massoniana and clarified the effect of PmSND4 on lignin and hemicellulose accumulation in transgenic poplar, providing important gene resources and a theoretical basis for understanding its potential role in wood quality improvement in P. massoniana. Full article