Mulching films are widely used to improve agricultural productivity; however, their residues can fragment during weathering and generate microplastics, posing potential environmental risks in farmland soils. Here, we collected polyethylene mulching films with well-documented natural exposure durations, i.e., fresh (Y0), and after 1 (Y1), 2 (Y2), and 3 (Y3) years in farmland, enabling a time-resolved assessment of in situ aging, and evaluated their thermochemical upcycling potential using Thermogravimetric-Fourier transform infrared spectroscopy (TG-FTIR) and Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Results showed that, during natural aging, the film surface became progressively rougher, developing numerous cracks and pores. Substantial amounts of oxygen were introduced into the film structure as O-containing functional groups (e.g., C=O, C-O-C, - OH), thereby increasing the carbonyl and hydroxyl indices. In addition, the contents of minerals such as Al, Si, Ca, Mg, and Fe within the films increased rapidly, leading to higher ash content and more residual solid after pyrolysis. Conversely, both the crystallinity and surface charge of the films generally decreased with prolonged exposure. Pyrolysis analysis revealed that, with aging, the proportion and amount of CO2 in the pyrolysis volatiles increased, while the contents of alkanes, alkenes, and cycloalkanes in the liquid products decreased; meanwhile, the yield of valuable oxygenates and other chemicals increased. This study reveals the natural aging process and potential resource utilization pathways of mulching film in farmland environments, providing a theoretical basis for addressing mulching film-related environmental issues.

With the improvement of technologies for the resource utilization of agricultural wastes, tobacco stalk biochar is gradually being applied to agricultural production in karst regions. However, the effects of tobacco stalk biochar application at different frequencies on soil quality and plant growth are poorly understood. Here, we integrated metagenomics with soil pseudo-targeted metabolomics to explore how tobacco stalk biochar application frequencies affect soil chemical properties, enzyme activities, microbial communities, metabolites, and plant growth. The results showed that annual application of an equal amount of tobacco stalk biochar could better promote tobacco growth by increasing soil available nutrients and enzyme activities. Microbial community analysis revealed that annual application recruited beneficial bacterial genera (Sphingomonas, Actinomadura and Variovorax), while biennial application enriched microbial diversity. Moreover, soil pseudo-targeted metabolomics analysis showed that the annual application significantly increased the amino acid content, while one-time application significantly increased the phenolic acid. Additionally, redundancy analysis revealed alkali-hydrolyzable nitrogen (AHN) and pH as primary environmental factors synergistically regulated soil enzymes, microbial communities, and soil metabolites, thereby forming a complex interaction network. Phenylalanine, glutamate, pyroglutamic acid, polyphenol oxidase, Bradyrhizobium, and Pseudolabrys are likely key factors in network for mediating the effects of tobacco stalk biochar application frequency. Our results indicated that soil enzymes, microbial communities, and metabolites collectively drove the optimal enhancement of soil quality and plant growth under the annual equal application, suggesting a potential ways to mitigate the negative effects in continuous cropping obstacles.

Tobacco (Nicotiana tabacum L.) is an important economic crop whose production is severely threatened by black shank and bacterial wilt, caused by Phytophthora nicotianae and Ralstonia solanacearum, respectively. Kunitz-type trypsin inhibitors (KTIs), as key components of plant innate immunity, play crucial roles in defense against biotic stress in various plant species. In this study, we systematically identified 22 KTI genes in N. tabacum genome and conducted a comprehensive analysis of their phylogenetic relationships, structural features, and expression patterns. By comparing transcriptomic profiles under colonization by the beneficial endophyte Piriformospora indica versus infection by the pathogenic fungus P. nicotianae, we identified a pathogen-specifically induced gene, NtKTI9. This gene was significantly activated upon infection by both P. nicotianae and R. solanacearum. Functional studies revealed that the NtKTI9 protein possesses trypsin inhibitory activity and exhibits antimicrobial capacity in vitro. Overexpression of NtKTI9 in tobacco activated the phenylpropanoid metabolism pathway, which promoted lignin deposition in the roots and enhanced plant resistance against both pathogens. Further mechanistic analysis showed that the expression of NtKTI9 is induced by jasmonic acid (JA) signaling, while its overexpression, in turn, strengthens JA signaling by regulating α-linolenic acid metabolism, suggesting a potential positive feedback loop that synergistically amplify plant immune responses. Based on gain-of-function evidence, this study indicates that NtKTI9 positively contributes to immune regulation in tobacco, which not only deepens our understanding of how KTI genes participate in plant immunity but also provides a novel candidate gene and theoretical foundation for molecular breeding of disease-resistant tobacco.

IntroductionGlucose in tobacco leaves acts as a vital chemical precursor that thermally degrades and reacts with amino acids during combustion and curing to enrich aldehydes, ketones, and nitrogen‐containing heterocyclic aroma compounds, thereby shaping flavor and masking harshness. However, current analytical methods for glucose quantification are limitations of high complexity, poor portability, and low eco-friendliness.MethodsA facile approach for on-site method for glucose determination in both flue‐cured and fresh tobacco leaves, based on aqueous extraction followed by test-strip reflectometric analysis, was developed.Results Design of experiments with central composite design was employed to achieve the ideal extraction conditions, with a shaking count of 70 times and a static immersion time of 36 min. The matrix effect in the aqueous tobacco extract showed a suppression effect with relative quantitative errors below 5.0%, and the test strip’s enzymatic reaction exhibited high specificity for glucose. The developed method showed a good linear relationship over the range of 2.00–90.0 mg/L (y = 0.9952× + 0.0253, R2 = 0.9991). The average recoveries ranged from 94.1% to 96.0% for flue‐cured tobacco and 95.0% to 97.5% for fresh tobacco leaves, with repeatability RSDs ≤ 3.86% and ≤ 4.51%, reproducibility RSDs ≤ 5.00% and ≤ 5.98%, respectively. Compared with the traditional derivatization GC‐MS method, the linear regression slope between the two methods was 0.9781 (r = 0.9997 and p < 0.01), and the overall AGREEprep score of test strip with reflectometry method was 0.78, further confirming both the excellent accuracy and greenness. Finally, this method was successfully applied to evaluate glucose variation among different cultivars and growth stages, demonstrating its practical applicability.DiscussionThis study developed a simple, portable, and green method for the determination of glucose content in different tobacco matrices, which could provide scientific reference data for tobacco quality evaluation and physiological growth monitoring.

Although plastic film mulching enhances tobacco yield and quality, its residues pose a threat to soil health. Herein, a field experiment was designed to investigate the impacts of polyethylene (PE) and poly (butylene adipate-co-terephthalate) (PBAT) residues on soil carbon pools throughout the tobacco growth cycle. Plastic film residues increased soil CO2 and CH4 emissions by 1.09-15.33% and 14.57-122.47%, respectively, with responses varying by polymer type and growth stage. PE residues inhibited the accumulation of soil organic carbon (SOC) fractions and weakened carbon pool stability, with the degree of inhibition regulated by residue concentration. Conversely, high levels of PBAT residues elevated total SOC but preferentially enriched active carbon pools, evidenced by a declining MAOC/SOC ratio. The rhizosphere microbial functional shifts driven by residual film accumulation are an important potential factor influencing soil carbon pool dynamics. Low-concentration PE residues had no significant impact on microbial functions, severe PE accumulation triggered oxidative stress and forced a selective gene function, shift toward efficient energy pathways, indicating metabolic inefficiency driven by stress. As an exogenous available carbon source, PBAT substantially enriched genes involved in carbon fixation and degradation, thereby stimulating microbial metabolism and accelerating rhizosphere carbon turnover. Enzyme activity measurements and targeted metabolomics analyses provided further evidence substantiating the microbial metabolic reprogramming processes suggested by functional gene profiling. This study elucidated how distinct plastic residues differentially regulate soil carbon cycling via microbial metabolic modulation, providing a scientific basis for the ecological risk assessment of mulch film residues.

ABSTRACT Biological amendment strategies effectively enhance the physical and chemical properties of continuously cropped soils, offering an environmentally sustainable and economically viable solution. This study investigated the impacts of distinct straw formulations on the cultivation performance of Stropharia rugosoannulata and associated soil microbial communities. Four treatments were established: R group (100% rice straw), C group (100% corn straw), TR group (10% tobacco stalk + 90% rice straw), and TC group (10% tobacco stalk + 90% corn straw). Employing a combined approach of field experiments and high-throughput sequencing, we systematically evaluated treatment efficacy through assessments of agronomic traits and nutritional quality of S. rugosoannulata, soil physicochemical parameters, and microbial community profiling. The TC group significantly enhanced S. rugosoannulata growth parameters, including height, cap thickness, stipe length, and fresh weight per individual fruiting body, outperforming pure straw treatments. The C group demonstrated the highest crude protein content (32.44%) among all treatments, while nicotine residues in tobacco-containing formulations remained below safety thresholds. Post-harvest incorporation of spent mushroom substrate (SMS) significantly increased soil organic matter (SOM), alkali-hydrolyzable nitrogen (AN), available potassium (AK), and available phosphorus (AP) contents, with the greatest increases observed in the TR group. Notably, the TC group promoted tobacco plant development between 40–80 days post-transplantation, evidenced by significant increases in plant height and leaf area expansion. All treatments substantially reduced incidence rates of tobacco black shank and brown spot disease, with the TR group reducing the incidence by 86.77% and 81.83%, respectively. Microbially, both TC and TR groups significantly enhanced the Chao1 index of soil bacteria and fungi, reduced the Simpson index, and promoted the enrichment of beneficial microbial genera (e.g., Actinobacteriota, Gaiella, and Mortierella), while inhibiting opportunistic pathogenic fungi (e.g., Neocosmospora and Scedosporium). βNTI model analysis revealed that drift and others (DR) primarily governed community assembly patterns, but the TC group uniquely intensified dispersal limitation (DL) effects on fungal community structure.IMPORTANCEDriven by the excessive pursuit of economic interests and limited soil resources, the intensive cultivation system centered on continuous cropping has become a critical component of agricultural production. However, this practice has led to soil nutrient depletion, escalated disease pressures, and root decay caused by soilborne pathogens, ultimately hindering healthy crop development. S. rugosoannulata cultivation is a non-expensive alternative to enhance soil health. Our study provides the first comprehensive characterization of different straw formulations, demonstrating exceptional potential for enhancing the yield and quality of S. rugosoannulata, improving the soil microecology in continuous cropping systems, and suppressing soil-borne diseases. These findings provide a scientific basis for sustainable field management and the recycling of straw resources.

To promote the green development of the tobacco logistics industry and realize resource utilization of its solid packaging waste, this study investigated plastic wrapping film (polyethylene, PE), logistics cardboard boxes (LCB), logistics wood strips (LWS), and cigarette packaging paper (CPP) as representative materials. Comprehensive analyses were conducted on their composition, surface functional groups, morphology, crystal phases, chemical bonds, and pyrolysis behaviors. Furthermore, the co-pyrolysis interactions and kinetic parameters of PE blended with LCB, LWS, or CPP were studied. The results showed that PE is mainly composed of C, H, and trace O, with C-H and-OH as dominant surface functional groups. In contrast, LCB, LWS, and CPP are rich in C, H, O, N, and S, with major surface functional groups of C=O,-C-O, C-H, and-OH, and contain substantial mineral particles or additives. PE displays high thermal stability, decomposes within a narrow temperature range (407 similar to 485 degrees C), and produces negligible solid residue after pyrolysis. During co-pyrolysis, there are strong interactions between PE and LCB, LWS, or CPP. Notably, the presence of minerals or additives in LCB can greatly mitigate the negative effects of PE softening, shifting the pyrolysis temperature of both LCB and PE to lower regions and reducing their activation energies to 11.43 and 16.53 kJ/mol, respectively. The study demonstrates that co-pyrolysis is a feasible approach for the resource utilization of solid waste from the tobacco logistics industry.

To investigate the effect of different mulching cultivation methods on soil carbon flux, continuous monitoring of soil carbon flux was conducted in tobacco fields in Kaiyang County, Guizhou Province, using the static chamber-gas chromatography method under three cultivation modes: no mulching (CK), mulching during half of the growth period (T1), and mulching throughout the full growth period (T2). The characteristics of soil carbon flux (including CO2 and CH4) were analyzed in combination with various environmental conditions. Results showed that the peaks of CO2 and CH4 fluxes under different mulching methods occurred on the 35th and 56th days after transplanting, and the fluxes followed an "M-shaped" double-peak curve during the tobacco growth period, with similar trends. Compared with CK, T1 and T2 increased the cumulative CO2 emissions by 16.49% and 48.75%, respectively, while T1 resulted in a 27.69% reduction in cumulative CO2 emissions compared to T2. The cumulative CH4 emissions under CK and T1 showed a net absorption effect, while T2 displayed a net CH4 emission effect. The diurnal CO2 flux maxima and minima occurred at 12:00-14:00 and 4:00-6:00, respectively, which corresponded closely to the variations in sampling temperature. The CH4 flux under CK, T1, and T2 peaked during the high-temperature period of the day (12:00-14:00). In summary, mulching cultivation methods significantly affect soil carbon flux in tobacco fields. Among these methods, mulching during half of the growth period (T1) achieves better carbon sequestration and emission reduction, making it a recommended cultivation practice for tobacco production in this region.

As an emerging contaminant, nanoplastics (NPs) could enter plant tissues through roots and leaves, posing threats to plant growth. Majority of the earlier studies have focused on the toxic effects of NPs after their uptake and the potential non-toxicological biological impacts. We found that 20 nm polyethylene NPs (PE-NPs) could rapidly induce stomatal closure in tobacco leaves after 1 h of exposure, along with increased reactive oxygen species levels and up-regulated expression of pathogenesis-related genes. These responses were similar to those induced by pathogen-associated molecular patterns (PAMPs), as in case of response to pathogen recognition. Subsequent multi-omics integration analyses of transcriptome, proteome, metabolome, and phosphoproteome revealed convergent and divergent responses of tobacco leaves to PE-NPs and the tobacco pathogen Pseudomonas syringae pattern-triggered immunity (PTI) responses. Tobacco leaves responded to both elicitors in a similar manner at the transcriptome and proteome levels, exhibiting numerous similar PTI response patterns, but distinct at the metabolome levels. The differences might arise from elicitor-specific phosphorylation events during post-translational modification, which reshaped gene expression by modulating enzyme activity, leading to distinct metabolite profiles. Our multi-level regulatory network revealed the molecular framework by which NPs as abiotic stressors activated plant innate immunity, providing a novel perspective for understanding the ecological impacts of NPs.

Long-term continuous cropping, low fertilizer use efficiency, and fixation of phosphorus and potassium in nutrient-deficient soils severely constrain sustainable tobacco production. Multifunctional plant growth-promoting rhizobacteria (PGPR) with robust environmental adaptability offer a promising strategy to reduce chemical fertilizer inputs. A multifunctional bacterial strain EL9 was isolated from tobacco rhizosphere and identified as Priestia megaterium. It showed a colorimetric value equivalent to 55.47 mg·L⁻1 IAA, solubilized 427.60 mg·L⁻1 phosphate, and mobilized 172.29 mg·L⁻1 potassium. Whole-genome sequencing revealed a 5.10 Mb genome carrying genetic features potentially involved in IAA production, including the tryptophan biosynthesis gene cluster and the amiE gene. Additional genes related to phosphorus transport, sulfate assimilation, and core carbon/nitrogen metabolism were also identified. Pot experiments showed that EL9 significantly increased IAA, available phosphorus, and potassium in rhizosphere soils of tobacco, Chinese cabbage, and wheat, accompanied by enhanced plant growth and root development. Field trials confirmed improved tobacco agronomic traits and cured leaf quality. Genomic safety assessment revealed no complete or obvious pathogenicity determinants based on in silico analyses, and additionally, plate assays suggested preliminary antagonistic activity against Fusarium oxysporum. Priestia megaterium EL9 is a promising multifunctional PGPR with a well-characterized genetic repertoire and showed promising efficacy in pot experiments across three crop species (tobacco, Chinese cabbage, and wheat) and in field trials with tobacco, supporting its potential as a biofertilizer for sustainable agriculture.

Poly (butylene adipate-co-butylene terephthalate) (PBAT) biodegradable mulch film may pose ecological risks to the soil environment. However, its environmental impacts on karst yellow soil remain unclear. Hence, this study combined 16S rRNA sequencing with soil pseudo-targeted metabolomics to investigate the effects of PBAT degradation at three dosage levels on karst yellow soil. Results showed that PBAT exerted dosage-dependent effects on soil available nutrients and enzyme activities. Specifically, alkali-hydrolyzable nitrogen (AHN) and available phosphorus (AP) decreased, while available potassium (AK) increased. Most soil enzymes generally increased in the early stage and stabilized in the later stage; however, soil polyphenol oxidase (S-PPO) exhibited a trend of initial promotion followed by inhibition. PBAT degradation drove the temporal succession of the bacterial communities, shifting them from a relatively stable initial state to a composition enriched in PBAT-degrading taxa (e.g., Sphingomonas, Novosphingobium, and Chujaibacter). This microbial shift was accompanied by the enrichment of metabolic functions associated with degradation. Soil pseudo-targeted metabolomic analysis revealed that PBAT degradation altered the soil metabolic profile. At the early stage (120 days), stress-response pathways were activated to maintain microbial homeostasis. At the later stage (240 days), metabolic activity shifted toward modulating amino acid, energy, and carbohydrate pathways in response to persistent degradation. Furthermore, a richer correlation network formed between soil bacteria and metabolites in the later stage. This study demonstrates that PBAT influences the soil bacterial microbiome and alters metabolome dynamics in karst yellow soil, providing a certain theoretical basis for understanding its ecological impact and guiding its safe application.

The adverse effects of microplastics (MPs) and nanoplastics (NPs) on plant growth have gained significant attention. However, the response of tobacco plants to polypropylene microplastics (PP-MPs) remains poorly understood. To address this, a microcosm experiment was conducted in which tobacco seedlings were exposed to PP-MPs at varying concentrations (100 and 1000 mg/kg) and particle sizes (20 nm and 100 µm) for 48 days in red soil. The physicochemical, transcriptomic, and metabolic responses of tobacco plants to PP-MP treatments were assessed. Our findings indicate that the effect of PP-MP exposure on tobacco growth was dose-dependent, with the higher doses (1000 mg/kg) inducing significantly stronger responses. Further, a significant accumulation of key metabolites in the phenylpropanoid and flavonoid biosynthesis pathways such as quercetin, phloretin, kaempferol, liquiritigenin, naringin, myricetin, ferulic acid, formaldehyde, and methyl eugenol was observed in response to PP-MPs. Additionally, the transcriptomic analysis revealed that higher doses enriched more DEGs than lower. KEGG pathway analysis identified significant enrichment in phenylpropanoid biosynthesis, flavonoid biosynthesis, sesquiterpenoid and triterpenoid biosynthesis, and plant hormone signal transduction. The notable variation in the expression of key enzyme-related genes such as PAL, CHI, CSE, C4H, 4CL, COMT, and CYP indicates the substantial impact on lignin synthesis. Lastly, large-sized PPMPs alter the activity of key lignin-degrading enzymes, affecting the lignin content. This study offers valuable insights into the responses of tobacco plants to varying concentrations and sizes of PP-MPs, integrating both physicochemical and molecular perspectives.

Tobacco (Nicotiana tabacum L.) is an important cash crop, but its yield, quality, and profitability are severely affected by bacterial wilt caused by Ralstonia solanacearum. There is currently no effective means to control tobacco bacterial wilt. This study reported a novel strategy to improve resistance to bacterial wilt and enhance the growth of tobacco. Magnesium oxide nanoparticles with concentrations of > 250 mg/L inhibited the growth of Ralstonia solanacearum while promoting Piriformospora indica growth. Magnesium oxide nanoparticles can bind to Piriformospora indica through electric field force. Compared with the single application of magnesium oxide nanoparticles or Piriformospora indica, co-application of magnesium oxide nanoparticles (250 mg/L) and Piriformospora indica (107 cfu/mL) demonstrated a superior promoting effect on tobacco growth and resistance to bacterial wilt. The magnesium oxide nanoparticles-Piriformospora indica combination strengthened the functions of magnesium oxide nanoparticles or Piriformospora indica on tobacco by inducing expression of the genes involved in pathogenesis (such as PTI and PR10a), immunity, reactive oxygen species detoxification, hormone signaling, and transcriptional regulation (such as WRKY). This combination shapes the microbial community to improve tobacco resistance to Ralstonia solanacearum, resulting in an increase in the abundance of beneficial bacteria such as Streptomyces, Nocardioides, and Micromonospora. Furthermore, an integrated analysis of the transcriptome, metagenomics, and soil metabolomics revealed the root-microbe interactional networks driven by the magnesium oxide nanoparticles-Piriformospora indica combination under Ralstonia solanacearum attack. This work highlights the advantages of the magnesium oxide nanoparticles-Piriformospora indica combination in tobacco production, providing an potential nanobiofertilizer for controlling tobacco bacterial wilt.

The mismatch between the solar spectrum and chlorophyll absorption peaks, combined with magnesium (Mg) and molybdenum (Mo) deficiencies in acidic soils, critically constrains photosynthetic efficiency and crop productivity. In this study, a multifunctional nanomaterial with dual-capabilities i.e. spectral-conversion and nutrient-supply—molybdate-intercalated (MoO42−) and europium (Eu3+)-doped layered double hydroxide (MgAlEu-MoO42−-LDH)—was applied to tobacco (Nicotiana tabacum L.) leaves as a phyllospheric regulator. Material characterization revealed that MgAlEu-MoO42−-LDH exhibited strong absorption in the ultraviolet region and efficiently converted the absorbed energy into red emissions at 610 nm and 706 nm, thereby optimizing the leaf-surface light environment. Scanning electron microscopy confirmed its uniform adhesion on the leaf surface. Compared with the control (CK) and the unreacted MgAlEu-MoO42−-LDH raw material (Raw), MgAlEu-MoO42−-LDH treatment significantly enhanced plant height, leaf area, net photosynthetic rate (Pn), chlorophyll content, and accumulation of photosynthetic carbon assimilate. The Mg and Mo contents in leaves increased markedly, while malondialdehyde (MDA) levels and antioxidant enzyme activities showed no significant changes, indicating effective nutrient supplementation and no evident phytotoxicity. Mechanism analyses with transcriptomics and metabolomics further revealed that MgAlEu-MoO42−-LDH upregulated multiple genes involved in photosystem electron transport and reprogrammed the phytohormone network (downregulation of indole-3-acetic acid (IAA) and abscisic acid (ABA), and upregulation of salicylic acid (SA)). Collectively, MgAlEu-MoO42−-LDH acts as a novel phyllospheric nano-regulator that synergistically couples “light-environment optimization” and “nutrient supply” to enhance photosynthetic efficiency and promote crop growth, providing a promising strategy for nanomaterial-driven sustainable agriculture.

ABSTRACT Multifunctional plant growth-promoting rhizobacteria (PGPR) have garnered significant attention in agricultural applications; however, a few have applied them in crop rotation or intercropping fields. To identify PGPR with strong colonization ability and broad spectrum benefit, we screened strains from the local tobacco rhizosphere and evaluated their growth-promoting effects across various crops and farming systems. In this study, strain L8, identified as Bacillus thuringiensis , was selected as a multifunctional PGPR capable of producing indole-3-acetic acid (IAA), solubilizing potassium, and mobilizing both organic and inorganic phosphorus. Compared with the control group, the soil treated with strain L8 in tobacco pot experiments showed significantly higher levels of IAA, available potassium, and available phosphorus. Furthermore, tobacco plants inoculated with L8 exhibited significantly improved growth parameters compared with the uninoculated control. The results indicated that compared with the control, strain L8 increased tobacco fresh weight (by 83.18%), plant height (by 29.32%), relative chlorophyll content (by 14.33%), as well as plant phosphorus (by 23.78%) and potassium (by 30.81%). Interestingly, L8 not only enhanced tobacco growth but also improved tobacco root morphology, significantly increasing root length (1.55-fold), root surface area (1.78-fold), and root volume (2.05-fold) compared with the control. These findings provide valuable insights into utilizing plant growth-promoting bacteria for tobacco production. Moreover, the inoculation strain L8 enriched soil organic matter and nutrient content in both wheat ( Triticum aestivum )-maize ( Zea mays ) rotation and peanut ( Arachis hypogaea )-maize intercropping systems. Furthermore, within the intricate tillage systems of wheat-corn rotation and peanut-corn intercropping, multifunctional PGPR strain L8 can play a crucial role in crop growth promotion, yield increase, and higher soil nutrient availability. IMPORTANCE These findings aim to study the application of plant growth-promoting rhizobacteria (PGPR) in diverse crops and complex planting systems, showing their adaptability and effectiveness in various agricultural contexts. The study suggests that this strain improves nutrient utilization in the soil, enhances soil health, and plays a significant role in plant growth through the secretion of substances like auxin (IAA). In parallel, we observed that applying this strain improved the production efficiency of wheat, corn, and peanuts within complex farming systems, indicating that this method holds the potential for enhancing both the yield and quality of various crops.

Soil microbial communities are crucial for essential ecosystem functions such as nitrogen cycling and organic matter decomposition. However, accurately classifying their gene sequences remains challenging due to overlooked taxonomic hierarchies, environmental variability, and insufficient structural dynamics. Current methods predominantly focus on intra-sequence nucleotide features while neglecting the community’s hierarchical taxonomy. To address these gaps, we analyzed soil samples collected from the loess regions of Guizhou and investigated dynamic changes in microbial community composition across plant growth stages. We propose MicroGraphBERT, a deep learning framework synergizing DNABERT’s context-aware embeddings with taxonomy-aware priors via graph attention network to enable joint modeling of sequence and ecological features for microbial classification. Trained on high-throughput sequencing data from the Guizhou loess regions, MicroGraphBERT integrates nucleotide-level contextual semantics from DNABERT and cross-species relational learning with graph attention network to capture both sequence features and taxonomic hierarchies. This approach identifies complex microbial patterns under varying soil conditions, achieving a classification accuracy of 98.72%. Our work advances precision microbiome analytics by providing a scalable solution for soil health monitoring, intelligent fertilizer optimization, and sustainable agroecosystem management.

IntroductionSmall molecule metabolites can act as soil conditioners to improve the soil environment and thereby promote crop growth. Like many other components of root exudates, succinic acid not only contributes to plant growth and stress resistance but also influences microbial growth in soil, thereby participating in the carbon cycle. Succinic acid is believed to act as a signaling molecule that bridges the host plant and microorganisms during their interactions. However, the mechanism by which succinic acid affects microbes, metabolites and their interaction in soil remains unclear.MethodsHigh-throughput sequencing and pseudotargeted metabolomics techniques were applied for exploring the effects of succinic acid in tobacco-planting soil and corresponding tobacco chemical composition.ResultsThe addition of succinic acid improved the soil chemical properties for increasing the available potassium, total nitrogen, total phosphorus and total potassium, and had a positive impact on soil fertility. In the microbial communities, fungi were more sensitive to succinic acid than bacteria. The relative abundance of Proteobacteria in the bacterial community was significantly decreased, while that of Chloroflexi was significantly increased. The relative abundances of Actinobacteriota and Acidobacteriota also showed a decreasing trend. The relative abundances of Ascomycota and Basidiomycota in the fungal community increased significantly, while the relative abundance of Chytridiomycota decreased significantly. The microbial function prediction indicated that 0.4% succinic acid may affected the nutrients and carbon-nitrogen cycles. In the soil metabolomics, the absolute contents of monosaccharide, disaccharide, sugar alcohol and trehalose in soil metabolites increased significantly. The 47 characteristic metabolites were significantly enriched in amino acid metabolism and carbohydrate metabolism. Correlation analysis showed that soil microbes were mainly positively correlated with amino acids and sugars. In addition, the relative abundances of monosaccharide, disaccharide and sugar alcohol increased in tobacco leaf, while alkaloid and amino acid decreased for improving the tobacco chemical composition.ConclusionThis study demonstrated that the addition of succinic acid affected soil chemical property, microbial communities and the composition of soil metabolites, and then improved crop chemical components.

Seed germination is vital for crop emergence and yield. Seed biopriming with beneficial microbes like Piriformospora indica has gained attention for promoting plant growth and stress tolerance. This study used tobacco as a model to explore P. indica’s germination-enhancing mechanisms through physiological and transcriptomic analyses via RNA-Seq under controlled laboratory conditions. Results showed P. indica enhanced lipid and starch degradation, upregulated related genes, and optimized sugar metabolism networks. In energy metabolism, P. indica reprogrammed genes in glycolysis, pyruvate metabolism, and the TCA cycle, forming an efficient energy-generating network. P. indica also activated phenylpropanoid biosynthesis genes and antioxidant enzyme activity, reducing oxidative stress. In summary, P. indica likely improves tobacco seed germination via metabolic remodeling, energy optimization, and oxidative defense. These findings offer insights into P. indica’s role in seed germination and hold promise for seed coating and early-stage biostimulant formulations in crops.

Poly (butylene-adipate-co-terephthalate) (PBAT) biodegradable mulch film has been considered a promising, environmentally friendly, and sustainable alternative to polyethylene. However, its long-term effects on crops and soil remain insufficiently understood. This study aimed to investigate the effects of PBAT mulch film with three application rates (0.05 g/kg, 0.5 g/kg, and 5 g/kg), as well as polyethylene (PE) mulch film (0.05 g/kg), on lettuce (Lactuca sativa L.) growth and soil microbial communities after 4-year pot experiment. The results indicated that the degradation of PBAT biodegradable mulch film in soil was significantly higher than that of PE. The concentrations of chlorophyll a, total chlorophyll, vitamin C, soluble protein, and nitrate in lettuce significantly increased in high application rates of PBAT mulch film. Soil urease (UR) activity increased with the increase of the PBAT application rates, whereas catalase (CAT) activity decreased. Moreover, the application of PBAT biodegradable mulch film significantly altered the composition of soil bacterial and fungal communities. The relative abundances of the bacterial genus Chujaibacter and Pseudolabrys increased with high PBAT application rates. Beneficial fungi such as Amphinema and Trichoderma showed an increasing trend, while pathogenic fungi exhibited the opposite pattern. These trends were also validated with the functional classification of bacteria and fungi. Overall, our findings suggest that PBAT mulch film application exerts significant effects on the soil micro-ecological environment and crop growth.