The fermentation of cigar tobacco leaves (CTLs) is a critical process driven by microbial activity, which directly influences the degradation of macromolecules and the development of distinctive aromas. However, mechanisms for the directional regulation of this process using defined microbial consortia remain underexplored. This study aimed to construct a synthetic microbial community (SynCom) to enhance the fermentation efficiency and quality of cigar tobacco leaves. Bacillus safensis and Bacillus velezensis with high extracellular cellulase, amylase and protease activities were screened out, and synthetic communities were constructed. This microbial community was applied to cigar tobacco leaves (cultivar QX204) during a 42-day fermentation. The SynCom significantly accelerated the degradation of key macromolecules, reducing cellulose, protein, and starch contents by 52.48 %, 56.36 %, and 68.47 %, respectively, which were markedly greater reductions than those observed in the uninoculated control. Microbiome analysis revealed that inoculation shifted the bacterial community structure, increasing the relative abundance of Firmicutes and significantly enriching the genus Bacillus. Metabolomic profiling identified 31 differentially accumulated volatile flavor compounds, including phenylacetic acid, phytol, and farnesol, which were upregulated in the BsBv group and contributed to enhanced honey, floral, and baked aromas, while reducing irritancy. Integrated multi-omics analysis indicated that these improvements were associated with key metabolic pathways, notably pyruvate metabolism, the pentose phosphate pathway, and glycerolipid metabolism. Furthermore, partial least squares path modeling (PLS-PM) elucidated that the SynCom consortium directly modulated chemical components and indirectly improved sensory quality by mediating shifts in microbial ss-diversity. These findings provide mechanistic insights into how functional SynComs can directionally improve tobacco leaf quality and offer a practical strategy for achieving efficient, high-quality cigar tobacco production.

Despite its widespread adoption in intensive agriculture, the ecological linkages between straw incorporation combined with nitrogen fertilisation, soil microbial processes, and crop productivity in wheat–tobacco rotations remain poorly understood. Here, a field experiment including three straw incorporation levels and four nitrogen application rates was conducted to evaluate their effects on soil properties, rhizosphere microbial communities, and tobacco yield. The results showed that straw incorporation significantly altered soil physicochemical properties and was strongly associated with shifts in rhizosphere microbial community composition. In particular, full straw incorporation promoted bacterial α-diversity and enriched copiotrophic taxa such as Proteobacteria and Bacteroidota. In contrast, nitrogen fertilisation primarily influenced soil nutrient availability and elicited comparatively weaker shifts in microbial community composition. Network analysis further indicated that straw incorporation was linked to greater microbial co-occurrence complexity and stronger positive associations among taxa. Partial least squares path modelling (PLS-PM) suggested distinct statistical relationships linking management practices, soil ecological responses, and tobacco yield. Straw incorporation showed stronger indirect associations with yield alongside coordinated changes in soil properties and microbial ecological attributes, whereas nitrogen fertilisation exhibited stronger direct associations with soil nutrient availability. The combination of full straw incorporation and moderate nitrogen input (R2N2) achieved the highest tobacco yield across all treatments.

Nanoplastics (NPs) are emerging environmental contaminants capable of penetrating plant tissues and disturbing cellular homeostasis. To elucidate cultivar-dependent tolerance mechanisms, two tomato (Solanum lycopersicum L.) cultivars, H1706 (H) and Rheinlands Ruhm (R), were exposed to 50 mg/L of 50 nm polystyrene nanoplastic (PS-NPs) in a hydroponic system for 14 days. Despite comparable NPs accumulation (H: 6.12 ± 0.6 mg/kg; R: 6.71 ± 0.5 mg/kg), cultivar H exhibited 41.97% greater biomass and 8.18% higher photosynthetic efficiency, as indicated by the maximum quantum efficiency of photosystem II (Fv/fm: 0.79 ± 0.02 vs. 0.73 ± 0.03) than R. Multi-omics (transcriptomics & metabolomics) analysis revealed that differentially expressed genes and metabolites were primarily enriched in the “photosynthesis” pathway (p < 0.01). Molecular dynamics simulations indicate that PS-NPs inserted into the cell membrane and disrupted the structure within approximately 400 to 1300 ns of simulation time, ultimately leading to chloroplast disorganization and excessive reactive oxygen species (ROS) formation. However, cultivar H maintained higher levels of both enzymatic antioxidants: peroxidase (POD; +16.07%) and superoxide dismutase (SOD; +19.21%); non-enzymatic antioxidants: glutathione (GSH; +14.76%) and ascorbic acid (AsA; +2.36%), and overall were 1.5–2.0-fold higher than those in cultivar R, leading to 35% lower ROS accumulation. Enhanced reduction-oxidation (redox) buffering preserved chloroplast integrity and sustained photosynthesis, conferring greater PS-NPs tolerance. This work demonstrates that integrating computational simulations with multi-omics can strengthen mechanistic understanding and improve toxicity prediction for plant-NPs interactions.

Soil cadmium (Cd) pollution significantly reduces both the yield and quality of pakchoi, posing potential health risks to consumers. This study aims to investigate the mechanism by which silicon (Si) mitigates Cd accumulation and enhances the yield and quality of pakchoi. The growth of pakchoi was inhibited when treated with 25 mu mol L- 1 CdCl2; however, the application of 1 mmol L- 1 Na2SiO3 significantly alleviated the inhibitory effects of Cd. Transcriptomic and physiological experiments demonstrated that Si application reduced Cd content in the roots and shoots by 39.96% and 61.59%, respectively, by modulating the expression of genes involved in Cd absorption and transport. Following Si application, the activities of catalase and ascorbate peroxidase increased by 2.79-fold and 2.01-fold. This enhancement in antioxidant capacity contributed to improved Cd tolerance. After Si treatment, the nitrate content in pakchoi leaves decreased by 66.14%. In contrast, the levels of vitamin C, glucosinolates, carotenoids, calcium, iron and zinc increased by 89.90%, 43.90%, 111.16%, 14.73%, 51.46% and 82.91% respectively. This enhancement in nutrient composition markedly improves the overall nutritional quality of pakchoi. These results indicate that Si application is an effective method to alleviate Cd stress in crops, providing a viable approach to enhance food safety in Cd-polluted areas.

High-throughput sequencing has generated extensive omics data for Nicotiana species, a key model genus in the Solanaceae family. However, fragmented data and limited cross-species integration in current databases hinder the identification of disease-resistant genes and germplasm innovation. To address these challenges, we developed Nicotiana multi-dimensional omics database (http://biodb.com.cn/NMOD/index.html). This database systematically integrates whole-genome data from 23 tobacco varieties, 168 transcriptome datasets, 777 million variation sites, and phenotypic-agronomic data from 146 global germplasm accessions. Nicotiana multi-omics database (NMOD) emphasizes the annotation of 29 disease-resistant gene families across 10 representative varieties, performs differential expression analysis on transcriptomes under different disease resistance treatments and integrates tools for genomic visualization (JBrowse), homology searching (BLAST), and functional enrichment analysis. In summary, NMOD provides extensive insights into tobacco genomics and genetics, holding promise to enhance future research on disease resistance mechanisms and molecular breeding in tobacco.

Crop diversification has been acknowledged as a means of lowering the environmental impact of agriculture without sacrificing agricultural output in recent years due to the growth of intensive agriculture. Crop rotation and intercropping—the methodical growing of two or more crops on one plot—are promising practices in this regard. Therefore, we conducted a quantitative bibliometric analysis of observed data between 2014 and 2024 to identify current research hotspots and future research trends in intercropping and crop rotation. A further secondary search for research advances in four key sub-areas (soil physicochemical properties, microbial diversity, greenhouse gas emissions (CO2, N2O, or CH4) and crop yield) was conducted based on keyword clustering. Our findings suggest that a crop diversification strategy can significantly increase soil nutrient content, optimize soil physicochemical properties, and regulate microbial community structure. In addition, this strategy can help to reduce greenhouse gas emissions (CO2, N2O, CH4), which will have a positive impact on the atmospheric environment. Crop diversification improves crop yield and quality, which in turn increases farmers’ economic returns. In order to maximize the effective production methods of crop rotation and intercropping, and to increase the efficiency of resource usage, this paper examines the development of research and practice on two cropping patterns worldwide.

Microplastics and various other contaminants are frequently present in soil. Here we investigated the long-term integrated responses of changes in the microbial community, metabolomics, heavy metal availability, and nutritional properties of the cadmium-cuprum-zinc-contaminated coastal saline soil to the three different microplastics. Various categories of microplastics had notable impacts on the available potassium, organic matter, availability of cadmium and cuprum, as well as the enzymatic activity in soil. Microplastics contamination caused diverse changes in microbial diversity and the composition of bacterial and fungal communities, resulting in the enrichment of Mortierella and a decrease of Bacillus abundance. The metabolites in soil primarily affected by microplastics contamination were the pathways involved organic acids and their derivatives, organoheterocyclic compounds, as well as lipids and lipid-like substances. Therefore, the addition of microplastics to soil may influence soil fertility, metal mobility, and alter the structure and metabolic processes of the microbial community in soil.

Continuous tobacco monocropping leads to soil degradation and yield reduction. To address this, we evaluated the effects of tobacco (Nicotiana tabacum L.)-woad (Isatis tinctoria L.) rotation (A2, A4) compared to tobacco monoculture (A1) and woad monoculture (A3) on soil health and crop quality over a multi-year period. Methods involved comparative analysis of soil nutrients, enzyme activities, microbial community structure, and crop chemical composition and economic value. Key results demonstrated that tobacco-woad rotation significantly improved soil fertility. The tobacco-woad rotation could increase the content of organic matter, alkaline available nitrogen, available phosphorus, and available potassium in the soil, which were increased by 1.44%, 17.96%, 4.61%, and 16.20%, respectively, compared to tobacco monoculture. Soil urease and catalase activities, particularly urease (increased by 2.31 times), were significantly enhanced during the tobacco pre-growth period under rotation. Soil microbial communities were significantly restructured under tobacco-woad rotation versus monocropping. Bacterial phyla Acidobacteria, Gemmatimonadota, and Methylomirabilota were enriched in tobacco-woad rotation (A2) relative to tobacco monoculture (A1), while Chloroflexi, Methylomirabilota, and Verrucomicrobiota increased in woad-tobacco rotation (A4) versus woad monoculture (A3). Fungal shifts featured decreased Ascomycota and Basidiomycota with increased Mortierellomycota in both rotations, alongside reduced Chytridiomycota in A4. Rotation enriched key bacterial genera (MND1, Nitrospira, Subgroup-10, and RB41) and fungal taxa (Mortierella, Saccharomyces, and Saitozyma). Crucially, rotation harmoniously improved the chemical composition of both tobacco and woad leaves, increasing reducing sugars, total sugars, nicotine, potassium, and the sugar ratio in tobacco. The proportion of high-quality tobacco leaves post-curing increased by 10.24% (A2), contributing to a significantly higher total crop production value. In conclusion, tobacco-woad rotation effectively alleviates soil degradation associated with continuous tobacco cropping by enhancing soil nutrient availability, boosting key enzyme activities, and optimizing the structure and interactions of the soil microbial community. These soil improvements collectively drive superior crop quality and economic returns, supporting their adoption as a sustainable agricultural practice.IMPORTANCE(i) The effects of rotation of tobacco with woad on the quality of tobacco production were clarified using physiological and biochemical analyses. (ii) The effects of rotating tobacco with woad on soil microorganisms were revealed by microbiome sequencing of tobacco soils. Tobacco-woad rotation significantly improved the relative abundance of soil-dominant bacteria and decreased the relative abundance of harmful fungi. (iii) An efficient cultivation model of tobacco and woad suitable for Shandong was established by combining soil microbiomics with tobacco plant growth and development. Rotation of tobacco to woad gave the best results.

The application of biostimulants is an effective strategy to enhancing plant growth and bolstering stress resilience. However, our understanding of the effects of polysaccharides from Ulva prolifera (PUP) on plant growth under abiotic stress remains limited. In this study, the effects of 100 mg/L (PUP-1), 300 mg/L (PUP-3), 500 mg/L (PUP-5) of PUP and water (CK) on the tobacco (Nicotiana tabacum L.) seedling growth in the acidic soil were compared by a microcosm experiment. The results indicated that PUP-1, PUP-3, and PUP-5 significantly increased the fresh weight by 24 %-70 %, respectively, potentially due to elevated levels of carotenoid, chlorophyll a, and chlorophyll b. PUP significantly improved properties and fertility of the acidic soil, such as pH, available potassium (S-AK), available phosphorus (S-AP), sucrase (S-SU), total nitrogen (S-TN), urease (S-UR), and acid phosphatase (S-APA). The abundances of some beneficial bacteria (Gemmatimonadaceae, Bacillus and Nitrospira) were enhanced by PUP-3 treatment, which might be associated with the increased pH and nutritional status of the soil. Moreover, the increase in the abundance of functional genes in biosynthesis pathways of carbon metabolism, amino acids, secondary metabolites, and fatty acids also demonstrated the positive effect of PUP amendments. Among them, PUP-3 (300 mg/L) treatment significantly promoted tobacco growth and optimized soil microbial composition, while higher concentrations (PUP-5) did not show further gains. In summary, the applications of PUP showed great potentials in the enhancement of plant growth in the acidic soil, and 300 mg/L is the optimal application concentration of this polysaccharide preparation in tobacco cultivation.

Nanoplastics (NPs) have become a new environmental pollutant that causes serious harm to food safety. They can be absorbed by plants, transported to edible parts, transmitted to the human body along the food chain, and can threaten human health. The research investigated the transport and accumulation pathways of polystyrene NPs (PS-NPs) at varying concentrations using red fluorescence labeling. An analysis was conducted on the response of pakchoi to PS-NPs through a combination of transcriptional and physiological experiments. PS-NPs enter the xylem vessel of the root, subsequently carried to the petiole through transpirational tension, and eventually transported from the petiole's xylem vessels to the leaf. PS-NPs induced the accumulation of reactive oxygen species (ROS), which led to oxidative damage. In addition, it also disturbed the homeostasis of endogenous hormones and affected the growth of pakchoi. These findings help people understand the adverse effects of NPs on crops and increase attention to the hazards of NPs.

Chrysanthemum morifolium, ‘Huangju’, is a golden chrysanthemum used for making tea. Limited by land resources, the continuous cropping of Chrysanthemum morifolium ‘Huangju’ has led to serious soil issues, which affects its yield and quality. In this study, different ratios of traditional Chinese medicine compound fertilizers were used to regulate the soil environment in order to achieve the green prevention and control of continuous cropping obstacles of the golden chrysanthemum. Five treatments were set up in the experiment: the control (CK) and different proportions of the Chinese herbal compound fertilizer T1, T2, T3, and T4. After the application of the traditional Chinese medicine compound fertilizer, the physical and chemical soil properties of the golden chrysanthemum were changed to varying degrees, resulting in an increased yield of golden silk chrysanthemum and an improved tea quality. This preliminary study on the application of the traditional Chinese medicine compound fertilizer T2 and T3—that is, Sophora flavescens–Stemona sessilifolia–Mentha haplocalyx–Perilla frutescens–Artemisia annua at ratios of 2:1:2:1:1.5 and 3:1:3:1:2—treatments provided the best results and can be further developed to alleviate the continuous cropping obstacles of fertilizers.

The widespread of plastics poses health risks through the food chain. While plenty of studies show plants absorb it through roots, but research on root responses to it is limited. This study explored the molecular mechanisms of tobacco seedling roots response to different polystyrene nanoparticles (PS-NPs) concentrations using multi-omics approaches. The results from confocal laser scanning microscopy indicated PS-NPs accumulate in root was proportional to concentration. PS-NPs reduced fresh weight by 19.1, 37.0, and 49.7 % in accompanied by increasing ROS. It is noteworthy that the lignin content was also significantly influenced, exhibiting an increase at low concentrations of PS-NPs and a decrease at high concentrations of PS-NPs. Compared to the control, the lignin content is 1.02, 0.87, and 0.83 times that of the control, respectively. To clarify the molecular mechanisms influencing the lignin content, a joint analysis of transcription-metabolism was conducted. It was found that ABA-related metabolites and genes first increased then decreased. In contrast, ethylene, which promote lignin degradation, showed an upward trend. It is likely that the dynamic balance between ABA and ethylene may influence lignin synthesis under PS-NPs treatment. This contribution not only clarified the impact of PS-NPs on plant root growth but also elucidated the potential mechanisms of phytotoxicity.

To elucidate the mechanisms of microbial fertilizers in enhancing tobacco growth and quality, this greenhouse-based pot experiment conducted over 40 days post-transplanting employed integrated microbiomics and metabolomics approaches to conduct a comparative analysis among conventional chemical, organic, and microbial fertilizers. Plant agronomic traits were systematically assessed at 20, 30, and 40 days post-transplanting, while soil physicochemical parameters were analyzed at the experimental terminus (40 days). The findings underscored the remarkable potential of microbial fertilizers in augmenting soil's quick-release nutrient pool and bolstering soil enzymatic activity, surpassing both chemical and organic counterparts. The application of microbial fertilizers accelerated tobacco growth and development, and significantly elevated agronomic indices, including plant stature, stem girth, leaf extension, and the abundance of aromatic precursors, thereby facilitating a marked improvement in tobacco leaf quality. Furthermore, the microbial community composition underwent pronounced alterations subsequent to the application of microbial fertilizers, with the emergence of pivotal microorganisms such as Rhodanobacter and Pseudolabrys within the treatment group. These microorganisms emerged as vital players in nutrient cycling processes, fostered plant growth, and mitigated the incidence of plant diseases. Microbial fertilizers demonstrated a significantly superior capacity to stimulate metabolic vigor in tobacco plants compared to other treatments, concomitant with a substantial enrichment of several metabolites, such as 3-methylindole. These data collectively imply that microbial fertilizers represent a more efficacious means of ameliorating soil physicochemical attributes, thereby fostering superior tobacco growth, development, and quality enhancement.IMPORTANCEIn recent years, there has been a surge in research examining the impacts of various fertilizers on the microbial composition of tobacco rhizosphere soils, and numerous studies have consecutively reported the growth-promoting mechanisms of diverse fertilizers on tobacco plants. However, despite these advancements, the existing body of literature remains inadequate in conclusively demonstrating the superiority of microbial fertilizers over traditional organic and inorganic fertilizers in tobacco cultivation. Consequently, our research aims to demonstrate the superiority of microbial fertilizers in enhancing plant growth by utilizing a comprehensive approach that integrates microbiomics and metabolomics techniques.

Cadmium (Cd) is a pervasive environmental pollutant with long-lasting detrimental effects on agriculture and human health due to its toxicity and bioaccumulation potential. While tobacco (Nicotiana tabacum L.) is recognized for its effectiveness in phytoremediation, the high Cd-accumulating variety NC55 exhibits poor tolerance to Cd. This study employed both soil culture and hydroponic systems to demonstrate that Nicotiana alata exhibits stronger Cd accumulation capacity and tolerance compared with NC55, while combinatorial analysis of transcriptome sequencing and physiological assays provided mechanistic insights into these adaptive responses. N. alata thrived in soil containing up to 40 mg center dot kg- 1 of Cd, achieving a Cd removal rate of 56.12 %, which rendered it suitable for heavily contaminated soils. N. alata displayed enhanced the activities of antioxidant enzymes, with superoxide dismutase and peroxidase levels being 1.40 and 1.86 times greater than those of NC55, respectively. We hypothesized that abscisic acid (ABA)-mediated cell wall remodeling underpins Cd tolerance of N. alata. Under Cd stress, N. alata exhibited enhanced ABA synthesis, along with significantly upregulated expression of PYR/PYL, SnRK2, and ABF genes in the ABA signal transduction pathway. This process activated lignin biosynthesis genes, resulting in a 33.62 % increase in lignin content compared with NC55, which thickened the cell wall and enhances Cd sequestration, thereby mitigating cellular toxicity. The application of sodium tungstate, an ABA synthesis inhibitor, decreased Cd tolerance in both varieties, emphasizing the role of ABA in the development of Cd tolerance. These findings highlight N. alata potential for Cd-contaminated soil remediation, offering a safe and efficient solution for heavily polluted soils.

Selenium and boron can alleviate lead (Pb) toxicity in plants, but their stress resistance mechanisms in tobacco remain unclear. The aim of this study was to investigate the effects of Se/B application on lead-induced oxidative stress, subcellular distribution, cell wall properties, and Pb accumulation. Additionally, a comprehensive analysis of transcriptomics and metabolomics data was conducted. Under Pb stress, the combined application of exogenous addition of Se, B and Se + B to a hydroponic system led to an increase in leaf biomass, promoted photosynthesis, increased antioxidant enzyme activity in tobacco, and significantly reduced the accumulation of Pb in the shoots of tobacco by downregulating the gene expression of the ABC transporter and upregulating the expression of aquaporin (AQP). Additionally, the application of Se and B increased the activity of the phenylpropanoid and glutathione metabolism pathways, promoting the synthesis of secondary metabolites such as coumarin, chlorogenic acid, ferulaldehyde, and (5-l-glutamyl)-l-amino acids. This, in turn, increased the tolerance of tobacco plants to Pb stress. Overall, our research findings provide new theoretical evidence regarding the roles of Se and B in alleviating Pb accumulation and offer potential strategies for the use of Se and B in the remediation of Pb-contaminated soils in agricultural production.

Continuous tobacco monocropping has caused soil degradation and yield reduction in China. Intercropping, as a specific and efficient cropping pattern, is highly associated with the enhancement of soil quality and land-use efficiency. Tobacco (Nicotiana tabacum L.)- Isatis (Isatis tinctoria L.) intercropping can significantly alleviate pests and diseases, and improve soil potential and fertility in tobacco fields. In this study, comparative analysis of three different tobacco-Isatis intercropping (B2, B3, B4) and tobacco monocropping (B1) on the soil nutrients, enzyme activities, and microbial community were conducted. B2, B3, and B4 importantly increased the contents of organic matter, available potassium, and available phosphorus content of the soil by 17.38%, 7.76%, and 2.78%, respectively. Moreover, B2 enhanced the activities of sucrase, urease, and catalase of soil by 2.35 times, 3.16 times, and 4.47 times, respectively, and B3 enhanced the activities of sucrase, urease, and catalase of soil by 2.74 times, 3.22 times, and 3.11 times, respectively. The intercropping pattern also optimized the structure of the soil microbial community. The relative abundances of Acidobacteriota, Chloroflexi, Gemmatimonadota, Planctomycetota, Nitrospirota, and Verrucomicrobiota in B3 and B4 were higher than those in B1. Positive links in soil bacterial correlation networks accounted for 47%, and soil bacteria formed a highly interactive and complex network. And compared with the B1, Ascomycota and Basidiomycota were lower abundance in B2 and B4, Ascomycota were lower abundance in B3 and Mortierellomycota were lower abundance in B2 and B3. Compared with monocropping, the chemical composition of tobacco leaves was harmoniously improved and the total production value of tobacco fields was significantly higher. The content of reducing sugar, total sugar, nicotine, potassium, and two-sugar ratio of leaves were increased after intercropping. The proportion of top-grade tobacco leaves after roasting in B2, B3, and B4 treatments were increased by 8.19%, 16.74%, and 27.32%, respectively. The study constructs insights into microbial community interactions at in tobacco/Isatis intercropping systems, and may facilitate the further development of tobacco/Isatis intercropping systems.

A new Asteraceae species, Ixeridium malingheense Z.Li & Q.Xu sp. nov., from Xingyi City, south-western Guizhou, China, is described and illustrated based on morphological and molecular analyses. Compared with the other species of the genus, the species is most similar to I. yunnanense in a small stature, linear-lanceolate stem leaves, and short phyllaries. However, it is easily distinguished from the latter by its smaller basal leaves 18–34 × 5–13 mm (vs. 10–25 × 5 mm), spatulate or long-spatulate (vs. elliptic, lanceolate, or oblanceolate), petioles ca. 30–55 mm (vs. 10 mm to absent), outer phyllaries 1-seriate (vs. 2-seriate, unequal), achenes smaller 2.0–3.0 × 0.5–1.0 mm (vs. 3.2 × 0.6 mm), and a flowering period of March to May (vs. June). Molecular phylogenetic analyses based on nuclear ITS sequence data determined the systematic position of I. malingheense in Ixeridium.

Unreasonable cultivation methods and management measures have led to widespread obstacles in tobacco continuous cropping in planting areas, resulting in reduced tobacco yield and soil degradation. Therefore, intercropping tobacco with other crops is an effective strategy to improve continuous cropping barriers. In this study, flue-cured tobacco NC102 and conventional planting varieties of Salvia miltiorrhiza were used as materials, and four treatments of flue-cured tobacco monoculture (CK), flue-cured tobacco, and Salvia miltiorrhiza at a ratio of 1:1 (TS11), 2:2 (TS22), and 2:3 (TS23), respectively, were set up to study their effects on soil microorganisms, physical and chemical properties, and yield and quality of flue-cured tobacco. The results showed that intercropping Salvia miltiorrhiza increased the number of soil bacteria and actinomycetes, decreased the number of fungi, and increased the activity of urease and sucrase. The content of available nitrogen and available phosphorus in intercropping Salvia miltiorrhiza soil was significantly higher than that of the flue-cured tobacco monoculture, while the content of available potassium was lower than that of the flue-cured tobacco monoculture. The soil environment was more conducive to the growth of flue-cured tobacco. Compared with the flue-cured tobacco monoculture, the proportion of superior tobacco in intercropping Salvia miltiorrhiza increased by 2.2–3.4%, and the ratio of potassium to chlorine in leaves of different parts of flue-cured tobacco increased by 12.3–75.0%. The content of total sugar and soluble sugar in middle and upper leaves of intercropping flue-cured tobacco was higher than that of the flue-cured tobacco monoculture, which improved the quality of flue-cured tobacco. From the analysis of the chemical composition of tobacco leaves, TS11 (flue-cured tobacco and Salvia miltiorrhiza intercropping row ratio of 1:1) had the best treatment effect, potassium content, total sugar, reducing sugar content, and potassium chloride ratio of flue-cured tobacco were the highest, the chlorine content was the lowest, and the quality was better than other treatments. From the analysis of total output value, the total output value of TS22 (flue-cured tobacco and Salvia miltiorrhiza intercropping row ratio of 2:2) was higher than that of other intercropping treatments. In 2018 and 2019, the total output value increased by 21.3% and 22.4%, respectively, compared with the flue-cured tobacco monoculture. The intercropping advantage was obvious, and the treatment effect was the best.

Nuclear factor Y (NF-Y) gene family is an important transcription factor composed of three subfamilies of NF-YA, NF-YB and NF-YC, which is involved in plant growth, development and stress response. In this study, 63 tobacco NF-Y genes (NtNF-Ys) were identified in Nicotiana tabacum L., including 17 NtNF-YAs, 30 NtNF-YBs and 16 NtNF-YCs. Phylogenetic analysis revealed ten pairs of orthologues from tomato and tobacco and 25 pairs of paralogues from tobacco. The gene structure of NtNF-YAs exhibited similarities, whereas the gene structure of NtNF-YBs and NtNF-YCs displayed significant differences. The NtNF-Ys of the same subfamily exhibited a consistent distribution of motifs and protein 3D structure. The protein interaction network revealed that NtNF-YC12 and NtNF-YC5 exhibited the highest connectivity. Many cis-acting elements related to light, stress and hormone response were found in the promoter of NtNF-Ys. Transcriptome analysis showed that more than half of the NtNF-Y genes were expressed in all tissues, and NtNF-YB9/B14/B15/B16/B17/B29 were specifically expressed in roots. A total of 15, 12, 5, and 6 NtNF-Y genes were found to respond to cold, drought, salt, and alkali stresses, respectively. The results of this study will lay a foundation for further study of NF-Y genes in tobacco and other Solanaceae plants.