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Background Root-to-shoot translocation of zinc (Zn) and cadmium (Cd) depends on the concentrations of both metals in the medium. A previous study on tobacco ( Nicotiana tabacum ) pointed to the contribution of NtZIP1, NtZIP2, NtZIP4 and NtIRT1-like in the regulation of this phenomenon. To learn more, Zn and Cd accumulation, root/shoot distribution and the expression of ZIP genes were investigated in the apical, middle and basal root parts. Results We show that Zn/Cd status-dependent root-shoot distribution of both metals was related to distinct metal accumulation in root parts. At low Zn and Cd in the medium, the apical part contained the highest metal level; at higher concentrations, the middle and basal parts were the major sink for excess metal. The above were accompanied by root part-specific expression pattern modifications of ZIPs ( NtZIP1-like, NtZIP2, NtZIP4A/B, NtZIP5A/B, NtZIP5-like, NtZIP8, NtZIP11, NtIRT1 , and NtIRT1-like ) that fell into four categories with respect to the root part. Furthermore, for lower Zn/Cd concentrations changes were noted for NtZIP5A/B and NtZIP5-like only , but at higher Zn and Cd levels for NtZIP1-like, NtZIP5-like, NtZIP8, NtZIP11, NtIRT1 , and NtIRT1-like. NtZIP1, here renamed to NtZIP5B , was cloned and characterized. We found that it was a zinc deficiency-inducible transporter involved in zinc and cadmium uptake from the soil solution primarily by the middle root part. Conclusions We conclude that regulation of the longitudinal distribution of Zn and Cd is highly specific, and that the apical, middle and basal root parts play distinct roles in Zn/Cd status-dependent control of metal translocation efficiency to shoots, including the stimulation of Zn translocation to shoots in the presence of Cd. These results provide new insight into the root part-specific unique role of NtZIP5B and other ZIP genes in the longitudinal distribution of zinc and cadmium and their contribution to the regulation of root-to-shoot translocation.

Tobacco is a model plant for studying flower coloration. Flavonoids and carotenoids were reported to contribute to the flower color in many plants. We investigated the mechanism underlying flower color formation in tobacco by comparing the profiling flavonoids and carotenoids between various species Nicotiana tabacum L. and Nicotiana rustica L., as their flowers commonly presented red (pink) and yellow (orange), respectively. The metabolomes were conducted by UPLC–ESI–MS/MS system. The main findings were as follows: (1) A total of 31 flavonoids and 36 carotenoids were identified in all four cultivars involved in N. tabacum and N. rustica . (2) Flavonoids and carotenoids tended to concentrate in the red flowers ( N. tabacum ) and yellow flowers ( N. rustica ), respectively. (3) About eight flavonoids and 12 carotenoids were primarily screened out for metabolic biomarkers, such as the robust biomarker involving kaempferol-3- o -rut, quercetin-glu, rutin, lutein, and β-carotene. This is the first research of systematic metabolome involving both flavonoids and carotenoids in tobacco flower coloration. The metabolic mechanism concluded that flavonoids and carotenoids mainly contributed to red (pink) and yellow (orange) colors of the tobacco flowers, respectively. Our finding will provide essential insights into characterizing species and modifying flower color in tobacco breeding through genetic improvement or regulation of featured metabolic synthesis.

Nicotiana tabacum L. (tobacco) has extremely high economic value, medicinal value, scientific research value and some other uses. Though it has been widely cultivated throughout the world, classification and change of its suitable habitats is not that clear, especially in the context of global warming. In order to achieve rational cultivation and sustainable development of tobacco, current (average from 1970-2000) and future (2070, average from 2061-2080) potential suitable habitats of Nicotiana tabacum L. were forecasted with MaxEnt model and ArcGIS platform based on 854 occurrence data and 22 environmental factors in this study. The results revealed that mean temperature of warmest quarter (bio10), annual precipitation (bio12), solar radiation in September (Srad9), and clay content (CLAY) were the four decisive environment variables for the distribution of Nicotiana tabacum L. Under current climate conditions, suitable habitats of Nicotiana tabacum L. were mainly distributed in south-central Europe, south-central North America, most parts of South America, central Africa, south and southeast Asia, and southeast coast of Australia, and only 13.7% of these areas were highly suitable. By the year 2070, suitable habitats under SSP1-2.6, SSP3-7.0, and SSP5-8.5 climate scenarios would all increase with the largest increase found under SSP3-7.0 scenario, while suitable habitats would reduce under SSP2-4.5 climate scenario. Globally, the center of mass of suitable habitats would migrate to southeast to varying degrees within Libya under four different climate scenarios. The emergence of new habitats and the disappearance of old habitats would all occur simultaneously under each climate scenario, and the specific changes in each area, combined with the prediction results under current climate conditions, will provide an important reference for the adjustment of agronomic practices and rational cultivation of Nicotiana tabacum L. both currently and in the future.

Tobacco ( Nicotiana tabacum L.) is a globally crop due to its distinctive flavor and economic value. In this study, we systematically analyzed the dynamic changes in volatile substances, broad-spectrum metabolites, enzymes, and biochemical compounds in tobacco leaves during flue-curing process. Combining metabolomics with enzyme activity and biochemical analysis, we identified that 43℃ is a critical period for enzyme activity and metabolite transitions, while 45 ℃ requires stringent moisture control. During the T3 stages, phenolic acids, amino acids, and derivatives were notably enriched, with increases of 19.58-fold, 18.59-fold, and 17.33-fold in lmmn001643, MWS20633g, and Lmhn004756, respectively. These compounds may serve as candidate biomarkers for non-volatile compounds. Aroma dynamics primarily contributed to the green and sweet flavor of flue-cured tobacco leaves, and the key aroma components included D114, KMW1317, and KMW0466. Differential volatile and non-volatile metabolites were enriched in four pathways, including monoterpenoid biosynthesis, tyrosine metabolism, phenylalanine metabolism, and phenylpropanoid biosynthesis. These pathways are closely related to phenylalanine ammonia-lyase and the synthesis of chlorogenic acid and rutin, which influence the aroma quality, aroma intensity, irritation, and volatility of tobacco. Additionally, the contents of caffeic acid, ferulic acid, sinapic acid, and PAL activity in phenylpropanoid biosynthesis pathway, increased with the rising temperature, accelerating reactions with alcohols and leading to increase lignin formation. This study enhances our understanding of the dynamic changes in the aroma and metabolic substances of Cuibi 1(CB-1) at the critical stages of the curing process and offers valuable insights for process improvement.

The nonenergy-conserving alternative oxidase (AOX) has been hypothesized to modulate the amount of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in plant mitochondria but there is sparse direct in planta evidence to support this. Laser scanning fluorescent confocal microscopy and biochemical methods were used to directly estimate in planta leaf concentrations of superoxide ( ), nitric oxide (NO), peroxynitrite (ONOO−) and hydrogen peroxide (H2O2) in wildtype (Wt) tobacco (Nicotiana tabacum) and transgenic tobacco with altered amounts of AOX. We found that plants lacking AOX have increased concentrations of leaf mitochondriallocalized and leaf NO in comparison to the Wt, while leaf concentrations of H2O2 were similar or lower in the AOX-suppressed plants. Based on our results, we suggest that AOX respiration acts to reduce the generation of ROS and RNS in plant mitochondria by dampening the leak of single electrons from the electron transport chain to O2 or nitrite. This may represent a universal role for AOX in plants. More work is now needed to establish the functional implications of this role, such as during abiotic and biotic stress.

Tobacco ( Nicotiana tabacum ), an allotetraploid species extensively cultivated worldwide, serves as a key model system for plant research but exhibits high susceptibility to insect pests. The comprehensive molecular mechanisms underlying N. tabacum ’s response to insect pests remain poorly characterized. In this study, we collected leaf RNA-seq samples from tobacco plants at 0, 6, and 24 h after exposing them to either the aphid ( Myzus persicae ) or the cotton bollworm ( Helicoverpa armigera ). The numbers of differentially expressed genes (DEGs) responding to cotton bollworms exceeded those responding to aphids at both 6 and 24 h. Pathway enrichment analysis, weighted gene co-expression network analysis (WGCNA), and clustered expression pattern analysis revealed that the most significantly enriched pathways were involved in hormone signal transduction, secondary metabolism, and the regulation of transcription factors. We employed CRISPR/Cas9 technology to disrupt Jasmonoyl-L-isoleucine hydrolase 1 (JIH1), which was significantly upregulated following insect treatment as confirmed by both RNA-seq and qRT-PCR analyses, to validate its role in insect resistance. The weight of cotton bollworms decreased by 25.67% when feeding on ntjih1-1 plants compared to wild-type (WT) plants. In ntjih1-1 plants, transcripts involved in jasmonic acid (JA), salicylic acid (SA), and ethylene (ET) signaling pathways were activated. Concurrently, plant height decreased, whereas primary root length increased. Interestingly, the expression levels of 13 of 15 JAZ genes were repressed in ntjih1-1 plants. The ntjih1-2 plants showed no enhanced resistance to cotton bollworms, potentially due to functional selective evolution of NtJIH1-1 and NtJIH1-2 during tobacco chromosome doubling. Our results indicate that JIH1 may play a vital role in balancing growth and defense in the plant’s immune response to herbivory.

Background SWEET (Sugar Will Eventually be Exported Transporter) proteins play vital roles in the transport of sugars, contributing to the regulation of plant development, hormone signaling, and responses to abiotic stress. Results In this study, we identified 57 NtSWEETs in tobacco ( Nicotiana tabacum L.), and then their physicochemical properties, chromosomal localization, synteny, phylogenetic relationships, genomic structure, promoter cis -elements, protein interaction network, tissue specificity, and expression pattern were systematically analyzed. In addition, NtSWEET12i improves drought and saline-alkali tolerance in tobacco by enhancing soluble sugars transport, ABA signaling, proline biosynthesis, and ROS scavenging. These findings illuminate the role of NtSWEETs , particularly NtSWEET12i , in regulating plant tolerance to drought and saline-alkali stresses. Conclusions This study offers new insights to enhance our understanding of the roles of NtSWEETs and identify potential genes involved in drought and saline-alkali tolerance of plants. Clinical trial number Not applicable.

Monoterpenes are important for plant survival and useful to humans. In addition to their function in plant defense, monoterpenes are also used as flavors, fragrances and medicines. Several metabolic engineering strategies have been explored to produce monoterpene in tobacco but only trace amounts of monoterpenes have been detected. We investigated the effects of Solanum lycopersicum 1-deoxy-D-xylulose-5-phosphate synthase (SlDXS), Arabidopsis thaliana geranyl diphosphate synthase 1 (AtGPS) and Mentha × piperita geranyl diphosphate synthase small subunit (MpGPS.SSU) on production of monoterpene and geranylgeranyl diphosphate (GGPP) diversities, and plant morphology by transient expression in Nicotiana benthamiana and overexpression in transgenic Nicotiana tabacum. We showed that MpGPS.SSU could enhance the production of various monoterpenes such as (−)-limonene, (−)-linalool, (−)-α-pinene/β-pinene or myrcene, in transgenic tobacco by elevating geranyl diphosphate synthase (GPS) activity. In addition, overexpression of MpGPS.SSU in tobacco caused early flowering phenotype and increased shoot branching by elevating contents of GA3 and cytokinins due to upregulated transcript levels of several plastidic 2-C-methyl-D-erythritol-4-phosphate (MEP) pathway genes, geranylgeranyl diphosphate synthases 3 (GGPPS3) and GGPPS4. Our method would allow the identification of new monoterpene synthase genes using transient expression in N. benthamiana and the improvement of monoterpene production in transgenic tobacco plants.

Purpose Flue-cured tobacco ( Nicotiana tabacum L.), a key economic crop in China, is highly dependent on nitrogen (N) management. This study evaluated the effects of multi-split N application via drip irrigation on tobacco growth, N accumulation, and nitrogen use efficiency (NUE). Methods A randomized experiment was conducted with 10 treatments (T0-T9) in K326 tobacco grown in nutrient-rich brown soil. The treatments differed in terms of N application timing and proportions. Results T2 and T3, which applied N twice post-transplant, led to the highest dry weight accumulation in roots, stems, and leaves, with T3 resulting in a 65.8% increase in root dry weight over that of T6. N accumulation followed the order of leaves > stems > roots, with T1 resulting in the highest total N accumulation, a 1.77-fold significant increase compared with that in T0 ( p  < 0.05). The fertilizer nitrogen (FN) was highest at T1 and T2, reaching nearly 46%, whereas T9 presented the lowest FN, decreasing by 22% compared with that at T1. T1 also retained the most N in the soil, whereas T3 had the highest N residues after the first top dressing. Uneven N applications resulted in significantly lower biomass and NUE. Conclusions These results highlight the importance of balanced multi-split N applications (T2 and T3) in improving dry matter accumulation, NUE, and crop quality. Optimizing N application through drip irrigation offers a promising approach to improving both yield and N management efficiency in flue-cured tobacco cultivation. Key points Flue-cured tobacco is crucial for China’s economy and relies heavily on sound N management. Multi-split nitrogen application via drip irrigation enhances growth and N use efficiency. Balanced N applications improve N accumulation and overall crop quality.

Nicotine exhibits obvious heterosis, which can be used to create Nicotiana tabacum L. (tobacco) varieties with varying nicotine content. However, the reasons for the formation of nicotine heterosis and its relationship to nicotine transport and accumulation remain unknown. This study conducted a comprehensive analysis of six tobacco hybrids with varying heterosis levels and their parent materials from various aspects, such as phenotype, physiology, and transcriptomics. The results showed that the direct path coefficient of transport heterosis to nicotine heterosis was highest in hybrids, at 0.98, and a highly significant positive correlation between the two. The plant height, thick stalk circumference, large flow of tissue fluid in the stalk, and high nicotine concentration of tobacco were the underlying factors that led to the strong nicotine transport capacity of hybrids. The formation of nicotine transport heterosis in hybrids was mainly influenced by non-additive gene effects (accounting for 89.93%), with over-dominant effects playing a dominant role (accounting for 58.79%). Among non-additive expression DEGs, nicotine transporter related multi antimicrobial extrusion protein, drug/metabolite transporter, ABC family transporter, and glutathione S-transferase were significantly upregulated in hybrid strains. The RT-qPCR results indicated that these genes related nicotine transport also exhibited heterosis at the expression level. Our results revealed that the formation of nicotine heterosis is mainly achieved by enhancing the nicotine transport capacity in hybrids. The results are not only beneficial for promoting the theoretical study of nicotine heterosis in tobacco and the breeding and utilization of hybrids, but are also of great significance for guiding nicotine production and promoting its multipurpose utilization.