Endogenous peer reward mechanisms have been shown to be effective in promoting contributions in public goods games (Yang et al. 2018). However, prior research has not shown whether such a mechanism itself is capable of being fully self-determined by decision-makers voluntarily. In a laboratory experiment, we endogenize the peer reward mechanism by allowing players to select their preferred fraction of total income in the public goods game to use for rewarding their peers’ public goods contributions. Players are then sorted into groups based on their declared fraction, with the group level fraction implemented as the minimum of a group’s individual preferences. We confirm that the reward mechanism successfully reverses the typical time decay in contributions found in public goods games, while maintaining high overall contribution levels, and in addition, implemented “tax” rates increase over time across all groups, demonstrating that players successfully learn the benefit of a higher fraction of income devoted to peer rewards. Contributions and reward vote-casting are both empirically increasing in the tax rate, and full contributions can be reached in practice at the 33% tax threshold. Our study shows that endogenous self-determination of sanctioning capacities and resource redistribution can be effective in sustaining high levels of cooperation.

Plant growth-promoting microorganisms (PGPMs) have shown great promise in enhancing plant development, improving stress tolerance, and modulating key physiological traits. However, their specific effects on cigar tobacco (Nicotiana tabacum) growth and leaf quality under controlled conditions remain poorly understood. In this study, we evaluated several PGPM inoculants, including Sinomonas atrocyanea, Bacillus velezensis, Bacillus cereus, Paenibacillus sp., Arthrobacter atrocyaneus, and other three Arthrobacter sp., for their effects on cigar tobacco growth and key quality traits under controlled conditions. Results showed that several treatments, particularly those containing Arthrobacter sp. and Bacillus velezensis, significantly increased total leaf number, leaf area, stem diameter, and plant height. These treatments also enhanced chlorophyll a and b accumulation, indicating improved photosynthetic capacity. Moreover, soluble sugar content and glandular trichome density, important indicators of flavor and aroma quality, were substantially elevated, Arthrobacter sp. showing the most pronounced sugar accumulation. These improvements are likely associated with microbial traits such as phytohormone production and nutrient solubilization. Our findings suggest that selected PGPMs can serve as effective biofertilizers for enhancing both biomass and quality-related characteristics of cigar tobacco, offering a viable pathway toward greener and higher-value tobacco production.

Cigar tobacco stands as a pivotal economic crop, with its leaf growth and development profoundly influenced by light intensity. Present study specifically aimed to investigate how leaf morphology and anticlinal growth responds to varying light intensities, including normal light intensity (NL–300 µmol m− 2 s− 1) and lower light intensity (LL–100 µmol m− 2 s− 1). The research elucidates significant morphological shifts in cigar tobacco leaves under LL, revealing significant alterations in leaf area, leaf length, and leaf width. Early reductions in leaf dimensions, ranging from 30 to 48

To investigate the deposition characteristics of droplets on the middle and lower leaves of cigar tobacco plants during field operations of a sprayer, this study employs the particle tracking technique within the Discrete Phase Model (DPM) of Computational Fluid Dynamics (CFD) and Two-way coupling technology between discrete and continuous phases. The motion characteristics of droplets under various spraying conditions were analyzed. The study selected mature cigar tobacco plants as the research subject. First, a complete solid model of the mature cigar tobacco plant was constructed using 3D scanning and reverse modeling techniques. Subsequently, the structural parameters of the sprayer were integrated to develop a simulation model for droplet deposition distribution. The simulation analyzed the droplet deposition characteristics on cigar tobacco leaves under nine operational parameter combinations, comprising three spraying pressures and three nozzle orifice diameters. The simulation results revealed that both spraying pressure and nozzle orifice diameters had significant impacts on the deposition performance of droplets on the leaf surfaces. To further validate the accuracy of the simulation model, field experiments were conducted. The field experiment results indicated that the droplet deposition density on both the front and back surfaces of the 17 leaves, from the bottom to the top of the plant, exhibited a consistent variation trend. For the front surface, the coefficient of determination (R2) was 0.7613, with a mean absolute error of 0.1855 mu L/cm2 and a standard error of 0.2438 mu L/cm2. For the back surface, the coefficient of determination (R2) was 0.7608, with a mean absolute error of 0.0582 mu L/cm2 and a standard error of 0.0837 mu L/ cm2. Therefore, the CFD simulation model adopted in this study could accurately predict the droplet deposition characteristics during field operations of the sprayer, providing valuable guidance for optimizing operational parameters in practice.

Introduction:Tobacco flower buds play a crucial role in enhancing the aroma quality of cigar tobacco leaves (CTLs). By incorporating tobacco flower bud extract into the fermentation process, this study investigates its effects on microbial community dynamics and the volatile aroma compounds in CTLs, aiming to improve cigar flavor and quality during fermentation. Methods:To investigate the effects of tobacco flower bud extract on microbial communities and aroma quality during the fermentation of cigar tobacco leaves, volatile aroma components were evaluated using gas chromatography-mass spectrometry (GC-MS). The microbial community dynamics across different fermentation stages were analyzed using metagenomic sequencing. Results and Discussion:Results revealed that tobacco flower buds contain 23 characteristic aroma compounds, including β-ionone and phenylethanal. Notably, the extract induced a pronounced microbial shift, enriching Aspergillus in unfermented leaves and promoting Staphylococcus dominance (97%-98%) during fermentation. This shift facilitated carbohydrate and protein degradation, significantly reducing nicotine content (P < 0.001), increased total sugar (12.5%-18.75%) and reducing sugar levels (13.04%-27.27%), and optimized the potassium-to-chloride ratio. Aroma analysis demonstrated significant enrichment of carotenoid degradation products (farnesyl acetone, citronellal) and Maillard reaction products (5-methyl-2-furaldehyde) in the FE group, with total aroma content increasing by 11.9% compared to control (FW). Metagenomic functional analysis further indicated that the extract inhibited pathways related to harmful metabolite synthesis (47.0% reduction) and enhanced carbohydrate metabolism (30.6% increasing). This study confirms that tobacco flower bud extract reshapes microbial communities and metabolic networks by simultaneously suppressing harmful microbes and enhancing aroma, providing theoretical support for optimizing cigar fermentation and agricultural waste utilization.

Air-curing is the initial step in the processing of cigar tobacco leaves. However, the dynamics of microbial community and metabolic functions in different parts of tobacco leaves during this process remain largely unclear. In this study, amplicon-based high-throughput sequencing revealed that Pseudomonas (9.0 to 29.9%) and Sphingomonas (0.5 to 13.8%) were the dominant bacterial genera in the early stages of air-curing, while Pantoea (1.7-90.4%) became predominant after air-curing. Microbial community diversity analysis indicated that species richness and diversity were significantly higher during the fresh leaf and withering periods. Functional prediction based on PICRUSt2 suggested that the microbial communities in the middle leaves exhibited higher abundances of metabolic pathways related to carbohydrates and amino acids than those in the upper leaves, potentially leading to the formation of more flavor compounds. The volatile flavor compounds were detected during the air-curing process by HS-SPME-GC-MS, with alkaloids and esters being the most prominent, although their accumulation periods differed across leaf parts. Furthermore, based on PLS-DA, 17 and 38 significantly changed flavor components were identified in the upper and middle leaves, respectively. Finally, the potential relationships between characteristic microbes and flavor components were explored based on Spearman correlation coefficient. It was found that multiple bacteria such as Rhodanobacter, Gemmatimonas, and Ramlibacter present in the middle leaves exhibited significant positive correlations with multiple flavor compounds such as 3,3-dimethylacrylic acid, phenylacetone, 2,3-butanedione, and geranylacetone, potentially promoting the flavor formation of cigar tobacco leaves during air-curing process. This study provides scientific insights into the role of microorganisms during the air-curing process of cigar tobacco leaves and offers a scientific basis for screening of specific functional microorganisms to improve and stabilize cigar tobacco flavor in the future.

The study of individual phenotypic information of cigar tobacco plants holds significant importance for enhancing mechanized production levels of cigar tobacco. It provides a foundational basis for the mechanization of field management, plant protection, and the design of harvesting machinery during the production process. Addressing the time-consuming, labour-intensive, inefficient, and highly subjective nature of traditional methods for extracting phenotypic information of cigar tobacco, this paper proposed a novel approach using terrestrial lidar scanning technology for the extraction of phenotypic information in field-grown cigar plants. By utilizing terrestrial lidar to acquire millimeter-precision three-dimensional point cloud data of individual cigar plants and conducting pre-processing of this point cloud data, the study employed a skeleton extraction algorithm based on Laplacian mesh contraction and topological refinement to construct a triangular mesh model of the leaves and a point cloud skeleton of the plant. Based on the triangular mesh of the leaves, this study extracted the leaf area, while the leaf length, leaf inclination angle, and petiole angle were derived from the plant's skeletal point cloud. Additionally, the plant height was ascertained from the point cloud of the cigar tobacco plant. The experimental results, compared with manual field measurements, indicated that the Root Mean Square Error values for actual leaf length, leaf area, leaf inclination angle, petiole angle, and growth height were 1.659 cm, 8.374 cm2, 2.371 degrees, 2.73 degrees, and 2.229 cm, respectively. The average absolute percentage errors for these measurements were 3.102 %, 0.782 %, 3.323 %, 4.148 %, and 1.194 %, respectively. This method provided an effective means of phenotypic information measurement to assist in the growth monitoring of mature cigar plants, mechanized plant protection, mechanized harvesting, and other projects that integrate agro-mechanics and agronomy.

Abstract Ustilago maydis is a pathogenic fungus in Basidiomycota causing corn smut disease. A strain of U. maydis YZZF202006 was isolated from the tumor of corn smut collected from Jingzhou city in China. The intracellular bacteria were confirmed inner hyphal of the strain YZZF202006 by PCR amplification and fluorescence in situ hybridization (FISH) and SYTO-9. An endohyphal bacterium YZUMF202001 was isolated from the protoplasts of the strain YZZF202006. It was gram-negative, short rod-shaped with smooth light yellow colony. The endohyphal bacterium was genomic evidenced as Klebsiella michiganensis on the basis of average nucleotide identity (ANI) analysis and the phylogram. Then K. michiganensis was GFP-Labeled and reintroduced into U. maydis, which confirmed the bacterium can live in hyphae of U.maydis. The bacterium can grow on N-free culture media. Its nitrogenase activity was reached av. 646.25 ± 38.61 nmol·mL− 1·h− 1 C2H4 by acetylene reduction assay. A cluster of nitrogen fixation genes (nifJHDKTXENXUSVWZMFLABQ) was found from its genome. The endohyphal K. michiganensis may play an important role to help nitrogen fixation for fungi in the future.

In a continuous-time version of the Bewley–Huggett–Aiyagari model, this paper shows theoretically and numerically that the fatness of the Pareto upper tail of the income distribution depends on tax progressivity only through the general equilibrium effect on the interest rate. With confiscatory taxes (marginal income tax rate approaching 100% at the top), the Pareto exponent is independent of tax progressivity.

Soil-borne diseases are closely related to rhizosphere microecosystem. While, plant species and genotypes are important factors affected rhizosphere microecosystem. In this study, the rhizosphere soil microbial community and metabolites of susceptible and resistant tobacco cultivars were investigated. The results showed that there were significant differences in the rhizosphere microbial community and metabolites between susceptible cultivar Yunyan87 and resistant cultivar Fandi3. Furthermore, the rhizosphere soil of Fandi3 showed a higher microbial diversity than that of Yunyan87. The abundance of R. solanacearum was much higher in the rhizosphere soil of Yunyan87 than in the rhizosphere soil of Fandi3, resulting in a higher disease incidence and index. While the abundance of beneficial bacteria in the rhizosphere soil of Fandi3 were higher than that of Yunyan87. Additionally, there were significant differences in metabolites between Yunyan87 and Fandi3 cultivars, and 4-hydroxybenzaldehyde, 3-hydroxy-4-methoxybenzoic acid, vamillic aldehyde, benzoic acid, 4-hydroxybenzyl alcohol, p-hydroxybenzoic acid and phthalic acid were notably high in Yunyan87. Redundancy analysis (RDA) indicated that the rhizosphere microbial community of Fandi3 and Yunyan87 were highly correlated with various environmental factors and metabolites. Overall, susceptible and resistant tobacco cultivars had different impact on rhizosphere microbial community and metabolites. The results expand our understanding of the roles of tobacco cultivars in plant-micro-ecosystem interactions, and provide a basis for the control of tobacco bacterial wilt.

Since its discovery as a third unique gaseous signal molecule, hydrogen sulfide (H2S) has been extensively employed to resist stress and control pathogens. Nevertheless, whether H2S can prevent tobacco bacterial wilt is unknown yet. We evaluated the impacts of the H2S donor sodium hydrosulfide (NaHS) on the antibacterial activity, morphology, biofilm, and transcriptome of R. solanacearum to understand the effect and mechanism of NaHS on tobacco bacterial wilt. In vitro, NaHS significantly inhibited the growth of Ralstonia solanacearum and obviously altered its cell morphology. Additionally, NaHS significantly inhibited the biofilm formation and swarming motility of R. solanacearum, and reduced the population of R. solanacearum invading tobacco roots. In field experiments, the application of NaHS dramatically decreased the disease incidence and index of tobacco bacterial wilt, with a control efficiency of up to 89.49%. The application of NaHS also influenced the diversity and structure of the soil microbial community. Furthermore, NaHS markedly increased the relative abundances of beneficial microorganisms, which helps prevent tobacco bacterial wilt. These findings highlight NaHS's potential and efficacy as a powerful antibacterial agent for preventing tobacco bacterial wilt caused by R. solanacearum.

The harvest time is a key factor for cigar leaves with high quality, which varies greatly depending on the environment. In this study, we performed a growth characterization of the cigar tobacco CX-26 ( Nicotiana tabacum L.) from the cluster stage to the vigorous stage and mature stage. Further, soil plant analysis development measurement of three middle leaves with 67 (T1), 71 (T2), and 75 days (T3) of growth after transplant indicates that the maturity might change from 71 to 75 days of growth. A genome-scale transcriptome was conducted to explore the gene expression dynamics of this maturity change. A total of 80,502 genes were detected in the CX-26 leaves, of which 64,611 genes were annotated on the reference genome. T1 and T2 leaves had fewer differential expressing genes (DEGs), while T3 leaves had 26,456 DEGs from T2 leaves, supporting the distinct growth of T3 leaves. Analyses of Gene ontology, Kyoto encyclopedia of genes and genomes identified that DEGs are involved inkey pathways including photosynthesis-antenna proteins, plant hormone/mitogen-activated protein kinase signaling pathway, and plant-pathogen interaction. Abscisic acid and jasmonate acids positively regulate leaf senescence and chlorophyll degradation and were higher in the T3 leaves compared with T1 and T2 leaves. In contrast, the total sugar was reduced in T3 leaves compared with T1 and T2 leaves, indicating the overripe state of the T3 leaves. Furthermore, several photosynthesis-related enzymes and a transcription factor were highlighted in the gene regulatory network, which might regulate the dynamics of carbohydrate metabolism, lipid metabolism, and energy metabolism. In summary, our study provides insight into the growth state of CX-26 cigar leaves.

The harvest time is a key factor for cigar leaves with high quality, which varies greatly depending on the environment. Here, we performed a genome-scale mRNA transcriptomic analysis on the cigar cultivar CX-26 (Nicotiana tabacum L.) to evaluate the relationship between gene expression and growth state. The leaves were harvested with 67 (T1), 71(T2) and 75 (T3)-day growth. A total of 80,502 genes were detected in the CX-26 leaves, of which 64,611 genes were annotated on the reference genome. Principal component analysis showed that T1 and T2 leaves had a high overlapping pattern, while T3 leaves were distinct. Indeed, T1 and T2 leaves had fewer differential expressing genes (DEGs), while T3 leaves had 26,456 DGEs from T2 leaves, supporting the distinct growth of T3 leaves. GO annotations mainly enriched the photosynthesis-related metabolic process, catalytic activity and binding biological processes. KEEG analysis identified the key pathways including photosynthesisantenna proteins, plant hormone/MAPK signaling pathway and plant-pathogen interaction. The maturity regulation and defense response-associated hormones abscisic acid and jasmonate acid were higher in the T3 leaves than that in T1 and T2 leaves confirming the KEEG analysis. Furthermore, several photosynthesis-related enzymes and a transcription factor were highlighted in the gene regulatory network, which might regulate the dynamics of carbohydrate metabolism, lipid metabolism and energy metabolism. In summary, our study provides insight into the growth state of CX-26 cigar leaves.

The lack of irrigation water in agricultural soils poses a significant constraint on global crop production. In-depth investigation into microRNAs (miRNAs) has been widely used to achieve a comprehensive understanding of plant defense mechanisms. However, there is limited knowledge on the association of miRNAs with drought tolerance in cigar tobacco. In this study, a hydroponic experiment was carried out to identify changes in plant physiological characteristics, miRNA expression and metabolite profile under drought stress, and examine the mitigating effects of selenium (Se) application. The shoot dry weight of drought-stressed plants was approximately half (50.3%) of that in non-stressed (control) conditions. However, plants supplied with Se attained 38.8% greater shoot dry weight as compared to plants with no Se supply under drought stress. Thirteen miRNAs were identified to be associated with drought tolerance. These included 7 known (such as nta-miR156b and nta-miR166a) and 6 novel miRNAs (such as novel-nta-miR156-5p and novel-nta-miR209-5p) with the target genes of squamosa promoter-binding-like protein 4 (SPL4), serine/threonine protein phosphatase 2A (PPP2A), cation/calcium exchanger 4-like (CCX4), extensin-1-like (EXT1) and reduced wall acetylation 2 (RWA2). Further investigation revealed that the expression levels of Ext1 and RWA2 were significantly decreased under drought stress but increased with Se addition. Moreover, key metabolites such as catechin and N-acetylneuraminic acid were identified, which may play a role in the regulation of drought tolerance. The integrated analysis of miRNA sequencing and metabolome highlighted the significance of the novel-nta-miR97-5p- LRR-RLK- catechin pathway in regulating drought tolerance. Our findings provide valuable insights into the molecular mechanisms underlying drought tolerance and Se-induced stress alleviation in cigar tobacco.

Tobacco prefers nitrate as a nitrogen (N) source. However, little is known about the molecular components responsible for nitrate uptake and the physiological responses of cigar tobacco to N deficiency. In this study, a total of 117 nitrate transporter 1 (NRT1) and peptide transporter (PTR) family (NPF) genes were comprehensively identified and systematically characterized in the whole tobacco genome. The NtNPF members showed significant genetic diversity within and across subfamilies but showed conservation between subfamilies. The NtNPF genes are dispersed unevenly across the chromosomes. The phylogenetic analysis revealed that eight subfamilies of NtNPF genes are tightly grouped with their orthologues in Arabidopsis. The promoter regions of the NtNPF genes had extensive cis-regulatory elements. Twelve core NtNPF genes, which were strongly induced by N limitation, were identified based on the RNA-seq data. Furthermore, N deprivation severely impaired plant growth of two cigar tobaccos, and CX26 may be more sensitive to N deficiency than CX14. Moreover, 12 hub genes respond differently to N deficiency between the two cultivars, indicating the vital roles in regulating N uptake and transport in cigar tobacco. The findings here contribute towards a better knowledge of the NtNPF genes and lay the foundation for further functional analysis of cigar tobacco.

A high yield cellulase production strain was screened from the surface of cigar wrapper leaves and added to cigar wrapper leaves for fermentation in the present study. The enzyme-producing strain was identified as Bacillus velezensis, and its maximum carboxymethyl cellulase activity could reach 44.3 U/mL. Making the cellulose degradation rate of cigar wrapper leaves as the index, the fermentation temperature, inoculum concentration, and carbon and nitrogen source addition concentration were optimized by response surface methodology. The results showed that under the conditions of inoculation concentration of 20%, fermentation temperature of 37 °C, addition of 4.5 ‰ glucose and 2.25 ‰ glutamate, the highest degradation rate of tobacco cellulose was 31.7%. Significance analysis results showed that the order of factors affecting the degradation rate of cigar wrapper cellulose was: inoculation concentration > carbon and nitrogen source addition concentration > temperature. The analysis of aroma substances under the optimal conditions found that the total amount of aroma substances of cigar wrapper increased by 26.1% compared with that before fermentation, in which β-damascenone, megastigmatrienone, farnesyl acetone, and solanone were significantly improved. The results were conducive to improving the aroma quality and concentration of cigar wrapper leaves.

Tax enforcement not only detects tax evasion (the direct effect) but also enforces voluntary compliance (the indirect effect). This paper explores implications of the indirect effect for the optimal size of the budget allocated to the Internal Revenue Service (IRS). The conventional wisdom prescribes that the size of the budget allocated to the IRS should always fall short of the level where an additional dollar allocated would return just an additional dollar of revenue. In a model where taxpayers are subject to a small amount of incomplete information, we show that after taking into consideration the indirect effect of tax enforcement, it is possible that the optimal prescription is opposite to the conventional wisdom.

在湖北恩施的连作土壤中分离出一种能够高效降解烟碱的细菌P3a,从形态结构特征、16S rDNA序列分析以及建构系统发育树等方面对其进行鉴定,结果表明P3a为节杆菌(Arthrobacter sp.).该菌株能在pH 7.0、温度37℃、230 r/min的条件下,36 h内对2 g/L烟碱的降解率为99.06％.并将菌株P3a应用到新鲜的烟叶中,发现它可以减少1 kg新鲜烟叶中55.11％的烟碱.鉴于其对烟碱的降解能力很强,可高效地应用于环境和烟草废弃物中烟碱降解.

不同品种雪茄烟叶晾制后叶色存在显著差异.本研究以晾制后的雪茄烟品种楚雪10号(CX-010)和楚雪14号(CX-014)烟叶为材料,运用液相色谱-串联质谱(LC-MS/MS)联用技术开展非靶向代谢组学分析,探索两品种烟叶在晾制后代谢物的相对含量差异及其与叶色的关系.结果表明,两个品种晾制后的烟叶代谢物相对含量存在显著差异.与CX-014相比,CX-010烟叶中游离氨基酸与生物碱相对含量总体较低,脂质相对含量总体较高,相差最大的32种差异代谢物包含2种氨基酸、10种酚酸、3种酰胺等物质.结合KEGG代谢通路分析,发现精氨酸和脯氨酸代谢通路中脯氨酸生物合成途径在两品种间差异显著.差异代谢物的生理功能分析显示,两品种烟叶晾制后的叶色差异主要与脯氨酸、水杨酸、黄酮类和生物碱的含量差异有关.

Tobacco-Specific Nitrosamines (TSNAs) are a class of common carcinogens that are widely present in cigarette products and smoke, which seriously affect the health of smokers and vastly restrict the safety of tobacco products. In our present research, the effects of Portulaca oleracea on nitrite scavenging and nitrosamine formation were evaluated through in vitro and tobacco field experiments. Further, four compounds Ferulic Acid O-Glucoside, Ellagic Acid, 13:4 + 4O Fatty Acyl Hexoside, and Feruloylmalic Acid were tentatively screened as potential Nitrate Reductase (NR) ligands by affinity ultrafiltration HPLC-MS. Molecular docking was then carried out to further verify the inhibitory activities of these potential ligands and elucidate their interaction mechanisms with NR. The results showed that P. oleracea exhibited substantial abilities in scavenging nitrite and blocking the formation of nitrosamines, which was mainly attributed to its abundant reductive components, especially its phenolics. In conclusion, the current study provided new insight into new strategies to reduce tobacco toxicity based on natural extracts, which is of great value to the tobacco industry.