Tobacco Varieties Research Articles

KARAKTERISASI MORFOLOGIS TEMBAKAU LOKAL KEBUMEN SEBAGAI UPAYA PELESTARIAN PLASMA NUTFAH

The tobacco plant is one of the plants cultivated in Kebumen Regency because it has high economic value compared to other plants. The varieties planted by farmers still use local varieties, namely Jero-Jlegi and Onthel. This variety has yet to be characterized, even though this tobacco plant is familiar to Kebumen farmers. The purpose of this study was to characterize morphologically and agronomically, namely, the production of local varieties of tobacco plants in Kebumen Regency, as an effort to preserve germplasm. The research was conducted in Peniron Village, Pejagoan District, Kebumen Regency. The results showed that the Jero-Jlegi variety tobacco plants had a plant height to the top leaf of 125cm, a plant height to a stem of 70 cm, a stem diameter of 2.5cm-3cm, a leaf length of 61cm, a leaf width of 36cm, a crown width of 109cm and a total of 10 leaves. The Onthel tobacco variety has a plant height to the top leaf of 131cm, a plant height to a stem of 66 cm, a stem diameter of 3cm, a leaf length of 67cm, a leaf width of 40cm, a crown width of 136cm and a total of 9 leaves. Ha) higher than the Onthel tobacco variety, 18.4 tons/day. Characterizing a plant will be very useful in selecting elders in a plant breeding program based on the variety's description. Keywords: tobacco, local, kebumen

Effects of cadmium on transcription, physiology, and ultrastructure of two tobacco cultivars

Cadmium (Cd) is one of the most toxic heavy metal pollutants worldwide. Tobacco is an important cash crop; however, the accumulation of Cd in its biomass is very high. Cadmium may enter the body of smokers with contaminated tobacco and the surrounding environment via smoke. Therefore, it is important to understand the mechanisms of Cd accumulation and tolerance in tobacco plants, especially in the leaves. In this study, the effects of Cd on the growth, accumulation, and biochemical indices of two tobacco varieties, K326 (Cd resistant) and NC55 (Cd sensitive), were studied through transcriptomic and physiological experiments. Transcriptome and physiological analyses showed differences in the expression of Cd transport and Cd resistance related genes between NC55 and K326 under Cd stress. The root meristem cells of NC55 were more severely damaged. The antioxidant enzyme activity, ABA and ZT content, chlorophyll content, photosynthetic rate, and nitrogen metabolism enzyme activity in K326 leaves were higher than in NC55. These data elucidate the mechanisms of low Cd accumulation and high Cd tolerance in K326 leaves and provide a theoretical basis for cultivating tobacco varieties with low Cd accumulation and high Cd resistance.

Transcriptomic and metabolic regulatory network characterization of drought responses in tobacco.

Drought stress usually causes huge economic losses for tobacco industries. Drought stress exhibits multifaceted impacts on tobacco systems through inducing changes at different levels, such as physiological and chemical changes, changes of gene transcription and metabolic changes. Understanding how plants respond and adapt to drought stress helps generate engineered plants with enhanced drought resistance. In this study, we conducted multiple time point-related physiological, biochemical,transcriptomic and metabolic assays using K326 and its derived mutant 28 (M28) with contrasting drought tolerance. Through integrative analyses of transcriptome and metabolome,we observed dramatic changes of gene expression and metabolic profiles between M28 and K326 before and after drought treatment. we found that some of DEGs function as key enzymes responsible for ABA biosynthesis and metabolic pathway, thereby mitigating impairment of drought stress through ABA signaling dependent pathways. Four DEGs were involved in nitrogen metabolism, leading to synthesis of glutamate (Glu) starting from NO-3 /NO-2 that serves as an indicator for stress responses. Importantly, through regulatory network analyses, we detected several drought induced TFs that regulate expression of genes responsible for ABA biosynthesis through network, indicating direct and indirect involvement of TFs in drought responses in tobacco. Thus, our study sheds some mechanistic insights into how plant responding to drought stress through transcriptomic and metabolic changes in tobacco. It also provides some key TF or non-TF gene candidates for engineering manipulation for breeding new tobacco varieties with enhanced drought tolerance.

Creation of New High-Productive Tobacco Varieties in the Sheki-Zakatala Economic Region

The article shows the implementation of selection and varietal studies on 70 samples, consisting of 35 varieties of tobacco collection nurseries and 35 hybrid selection materials, at the Zakatala Regional Experiment Station in the Sheki-Zakatala economic region. It was determined that the height of the plant in the collection area varied between 170 (Samsun-155, Samsun short) and 335 (106 blue form) cm. Thus, in the conditionally named Selected-2016 form, the height of the plants was 268 cm, and in the Virginia AZ form it was 282 cm. The maximum number of leaves was 50 in Zakatala Dubek varieties. The dimensions of the leaf blade were the highest in the Krupnolist variety with a width of 37 cm, and in the Virginia KY 160 variety with a length of 62 cm. Vegetation periods varied between 107-132 days. The height of the plant in the selection area varied between 180-295 cm. Thus, the height of the plants differed from the others with the highest being 295 cm in Virginia-20 × Zakatala Dubek and Virginia-20 × 106 blue form hybrids. The number of leaves was 49 in Virginia-20 × Zakatala Dubek form. The dimensions of the leaf blade were observed to be 64 cm in length in Virginia NC-71 × Zakatala Dubek × Virginia-20 complex pollination, and 37 cm in width in 106 blue form × Burley-122 hybrid. Vegetation periods varied between 115-129 days. In the collection area, it was observed that the highest yield indicator was 39.0 hwt/ha in Burley TN-90 varieties, and the lowest was 27.1 hwt/ha in Samsun short stature variety. Zakatala Dubek variety has the highest yield of commodity type I-II 90%, III-IV-10% and it differs from others. In the hybrid field, the highest yield index was 39.7 hwt/ha in the blue form of Virginia-20 × 106, and the lowest was 27.9 hwt/ha in the Virginia-548 × Virginia KY-160 variant. Virginia-20 × Zakatala Dubek variant had the highest yield of commodity species I-II 92%, III-IV-8% and differed from others. In 2021, 11 new hybrids were obtained as a result of selection works.

The NtSPL Gene Family in Nicotiana tabacum: Genome-Wide Investigation and Expression Analysis in Response to Cadmium Stress.

The SQUAMOSA promoter binding protein-like (SPL)SPL family genes play an important role in regulating plant growth and development, synthesis of secondary metabolites, and resistance to stress. Understanding of the role of the SPL family in tobacco is still limited. In this study, 42 NtSPL genes were identified from the genome of the tobacco variety TN90. According to the results of the conserved motif and phylogenetic tree, the NtSPL genes were divided into eight subgroups, and the genes in the same subgroup showed similar gene structures and conserved domains. The cis-acting element analysis of the NtSPL promoters showed that the NtSPL genes were regulated by plant hormones and stresses. Twenty-eight of the 42 NtSPL genes can be targeted by miR156. Transcriptome data and qPCR results indicated that the expression pattern of miR156-targeted NtSPL genes was usually tissue specific. The expression level of miR156 in tobacco was induced by Cd stress, and the expression pattern of NtSPL4a showed a significant negative correlation with that of miR156. These results suggest that miR156-NtSPL4a may mediate the tobacco response to Cd stress. This study lays a foundation for further research on the function of the NtSPL gene and provides new insights into the involvement of NtSPL genes in the plant response to heavy metal stress.

Yield of tobacco varieties and commodity of tobacco raw material under different plant placement schemes in the conditions of the central Forest Steppe of Ukraine

Yield of tobacco varieties and commodity of tobacco raw material under different plant placement schemes in the conditions of the central Forest Steppe of Ukraine

Topping and grafting affect the alkaloid content and gene expression patterns of tobacco (Nicotiana tabacum L.).

In this study, we aimed to determine molecular mechanisms underlying the effects of topping and grafting in tobacco (Nicotiana tabacum L.) by comparing the alkaloid contents and enrichment pathways of differentially expressed genes (DEGs) among plants subjected to different combinations of topping and grafting treatments. Plants of the tobacco variety "Zhongyan 100" and eggplant (Solanum melongena L.) were grafted in four combinations as scions and rootstocks, respectively. The four treatment groups were tobacco with topping, tobacco without topping, topped tobacco grafted onto an eggplant rootstock, and non-topped tobacco grafted onto an eggplant rootstock. Tobacco leaves were collected on the day of topping, at 7days after topping, and after flue curing, the alkaloid contents of the collected leaves were determined. Leaves of plants subjected to the different treatments were collected for RNA sequencing and screened for DEGs, which were subsequently subjected to functional enrichment analyses. Analyses revealed reductions in the leaf alkaloid contents of tobacco subjected to combined topping and eggplant grafting. Gene annotation indicated that topping influences biological processes such as starch metabolism and stress response, whereas grafting affected the biosynthesis and metabolic pathways of secondary metabolites. Downregulated DEGs between non-topped tobacco and eggplant-grafted topped tobacco and between topped and non-topped tobacco are mainly involved in inositol phosphate metabolic and biosynthetic processes. Downregulated DEGs between different grafting methods (eggplant-grafted non-topped tobacco vs. non-topped tobacco and eggplant-grafted topped tobacco vs. topped tobacco) are mainly involved in sesquiterpene synthase activity and photosynthesis. The findings of this study provide important insights into the molecular mechanisms underlying the effects of topping and grafting on tobacco plants.

Inheritance of yield-related morphological characteristics in F1 tobacco hybrids

The aim of this work was to study the mode of inheritance of the number of leaves per stalk and the length, width and area of the leaves from the middle part of the stalk - traits directly related to the yield in the offspring of the first generation. The studies were made with four mother parent tobacco varieties of different types (three of the Prilep type: P-23, ? 18-50/4, ? 76/86 and one of the Basmak type - ?? 8/1), one pollen donor parent Burley B-1-91, and their four F1 hybrids. The crosses were made in 2018, 2019 and 2020, and the experiment with the parent genotypes and their hybrids was set up in 2019, 2020 and 2021, on a field trial at the Scientific Tobacco Institute - Prilep in a randomized block design with four replications. All appropriate cultural practices were applied during the growing season. The research data indicates that there was no heterosis in the hybrids for the studied traits. The partially dominant mode of inheritance is an indicator of good successive selection of individuals in future generations and quick fixation and stabilization of the traits. The hybrids MS 8/1 ? B-1/91 and P 18-50/4 ? B-1/91 represent very interesting material for future tobacco breeding activities.

Transgenic tobacco plant overexpressing ginkgo dihydroflavonol 4-reductase gene GbDFR6 exhibits multiple developmental defects.

Dihydroflavonol Q 4-reductase (DFR), a key enzyme in the flavonoid biosynthetic pathway in plants, significantly influences plant survival. However, the roles of DFR in the regulation of plant development are largely unknown. In the present study, phenotypes of transgenic tobacco plants overexpressing the Ginkgo biloba DFR gene, GbDFR6, were investigated. Transgenic tobacco seedlings exhibited relatively low fresh weights, long primary roots, decreased lateral root numbers, and impaired root gravitropic responses when compared to wild-type tobacco plants. Adult transgenic tobacco plants exhibited a considerably high percentage of wrinkled leaves when compared to the wild-type tobacco plants. In addition to the auxin-related phenotypic changes, transgenic tobacco plants exhibited delayed flowering phenotypes under short-day conditions. Gene expression analysis revealed that the delayed flowering in transgenic tobacco plants was caused by the low expression levels of NtFT4. Finally, variations in anthocyanin and flavonoid contents in transgenic tobacco plants were evaluated. The results revealed that the levels of most anthocyanins identified in transgenic tobacco leaves increased. Specifically, cyanidin-3,5-O-diglucoside content increased by 9.8-fold in transgenic tobacco plants when compared to the wild-type tobacco plants. Pelargonidin-3-O-(coumaryl)-glucoside was only detected in transgenic tobacco plants. Regarding flavonoid compounds, one flavonoid compound (epicatechin gallate) was upregulated, whereas seven flavonoid compounds (Tamarixetin-3-O-rutinoside; Sexangularetin-3-O-glucoside-7-O-rhamnoside; Kaempferol-3-O-neohesperidoside; Engeletin; 2'-Hydoxy,5-methoxyGenistein-O-rhamnosyl-glucoside; Diosmetin; Hispidulin) were downregulated in both transgenic tobacco leaves and roots. The results indicate novel and multiple roles of GbDFR6 in ginkgo and provide a valuable method to produce a late flowering tobacco variety in tobacco industry.

Microbial network and composition changes according to tobacco varieties and interferes differently in black shank disease defense.

The soil-borne oomycete pathogen Phytophthora parasitica can cause black shank disease in tobacco plants. The use of resistant varieties can be used to control black shank disease. The potential relationships of the composition of the rhizosphere microbiome to resistance to black shank disease are poorly understood. This work aims to compare the rhizosphere microbial community and network of the tobacco resistant variety HB202 with the susceptible variety XY3. Rhizospheric soils were collected from tobacco plants of HB202 and XY3 in the fields with same soil types and agricultural operations. The compositions of the rhizosphere microbial communities were revealed by Illumina sequencing of bacterial 16S rRNA genes and fungal spacer (ITS) sequences and analysed with molecular ecological network pipeline. The alpha diversity of fungal communities of the two varieties was significantly different. The structure and composition of bacterial and fungal communities in the resistant variety in the rhizosphere was different from the susceptible variety. Relative abundances of beneficial genera in the HB202 microbiota were higher than in the XY3. Conversely, the XY3 microbiota exhibited a higher abundance of deleterious genera compared to the HB202 microbiota. The resistant variety influences the topological properties and microbial interactions in the rhizosphere against the disease. The network of the HB202 was more complex and had higher connectivity compared to the XY3 network. The rhizosphere microbial communities and networks of two tobacco varieties are very different. These changes in the microbial communities and their interactions may play an important role in tobacco resistance to black shank disease.

Analysis of Agricultural Input Resources on Chopped Tobacco Production of Reket and Seram Varieties in Suralaga District East Lombok Regency

Tobacco is a leading commodity that has high economic value. The tobacco products industry has a major contribution to the structure of state revenues through excise taxes, employment and sources of farmers' income. This research aims to; 1) explain the relevance of the characteristics of farmers and the production of chopped tobacco in Suralaga sub-district, East Lombok Regency; 2) analyze the influence of farming input resources on the production of reket and seram tobacco varieties in Suralaga District, East Lombok Regency. The research was conducted in Suralaga District, East Lombok Regency. The study was conducted from July 2021 - November 2021. The sampling method used purposive sampling as many as 40 farmer respondents who run tobacco farming. The data analysis method used in this research is quantitative analysis with multiple linear regression approaches. The results of the research show that the agricultural input resource variables that affect the production of tobacco farming are tobacco farming land variables, pesticides, labour, farming experience, and age. While the dummy variables in this study, namely the gender and variety types were also stated as variables that had an effect on tobacco production.

Differentially enriched fungal communities in root rot resistant and susceptible varieties of tobacco (Nicotiana tabacum L.) under continuous monoculture cropping.

Root rot is a major disease of tobacco that causes crop losses of up to 15-20% of global tobacco production. The present study aimed to compare the fungal communities, and physicochemical properties of rhizosphere soil of root rot resistant (Yunyan 87; Y) and susceptible (Honghua Dajinyuan; H) tobacco varieties. Four treatments of each variety under continuous monocropping cultures included: control groups (HT0 and YT0); 2 years of continuous cropping (HT2 and YT2); 4 years of continuous cropping (HT4 and YT4); and 8 years of continuous cropping (YT8 and HT8). The soil physicochemical properties including available nitrogen (AN), available phosphorus (AP), available potassium (AK), and organic matter (OM) were increased (p < 0.05) from HT0 to HT8, whereas the resistant variety (Y) showed an inconsistent trend from YT0 to YT8. The pH was decreased (p < 0.05) from HT0 to HT8 and YT0 to YT8. Further, the disease incidence rate and disease index of the H variety also increased (p < 0.05) from HT0 to HT8. Alpha diversity analysis revealed that susceptible variety had higher fungal diversity from HT0 to HT8, while resistant variety exhibited lower diversity from YT0 to YT8. Ascomycota and Mortierellomycota were the dominant phyla in H and Y. Ascomycota abundance was increased (p < 0.05), whereas Mortierellomycota was decreased (p < 0.05) for continuous cropping years in H and Y. Penicillium, Fusarium, and Chrysosporium were the top three abundant genera in both varieties. The relative abundance of Penicillium spp. was increased (p < 0.05) in Y, whereas decreased (p < 0.05) in H variety. Specifically, Chrysosporium spp. was increased (p < 0.05) whereas Fusarium spp. was decreased (p < 0.05) in YT2. Redundancy analysis (RDA) revealed that fungal communities in H and Y rhizospheres were influenced by pH and carbon content, respectively. The top three highly enriched (p < 0.05) pathways in both varieties were fatty acid elongation, fatty acid β-oxidation I, and glyoxylate cycle. Our study concluded that resistant variety exhibited lower fungal diversity and functionally enriched metabolic pathways than susceptible variety that might be the result of molecular breeding practices, however, the relative abundance of Penicillium spp. were increased in resistant variety under long-term monoculture cropping.

Identification of superior haplotypes and candidate genes for yield-related traits in tobacco (Nicotiana tabacum L.) using association mapping

Tobacco is an industrial crop, and its leaves and stems are used to produce cigarettes, cigars, pipe tobacco, and to extract bioethanol and biofuel. However, knowledge of the genetic basis underlying agronomic traits related to quality and yield in tobacco is limited. Therefore, we undertook association mapping to identify quantitative trait nucleotides (QTNs) associated with seven yield-related traits in 94 natural tobacco accessions using 126,602 SNPs and two multi-locus models. The mapping identified 465 QTNs across five environments for stem girth (SG: 84 QTNs), leaf number (LN: 61), SPAD (76), leaf length (LL: 71), leaf width (LW: 71), leaf length to width ratio (LLW: 58), and node distance (ND: 67), with phenotypic variance ranging from 0.46% to 30.99%. Of these, 45 reliable QTNs were found in multiple environments and detected by both methods. In addition, the mapping identified 16 pleiotropic QTNs for different traits, e.g., pQTN-18–13 on Chr18 associated with all traits except SG. For 43 QTNs, yield-related traits significantly differed between superior and alternative alleles, with 13 forming haplotype blocks with 3–5 haplotype groups. We screened 15 putative candidate genes based on the 13 haplotype QTNs for yield-related traits, e.g., PCK1, ECR1, MTACP1, SMC6B, and FH14. To the best of our knowledge, this is the first study to identify superior haplotypes associated with yield-related traits, providing a foundation for genetic studies, map-based cloning, and molecular breeding to improve tobacco varieties with desirable yield-related traits.

The Effect of Various Cultivation Methods on the Yield and Quality Indicators of Nicotiana tabacum

In 2018-2020, the experiment was laid on a site with one type of relief. The experiment was carried out in 4 repetitions, 4 rows in each section, the length of each row was 10 meters. Soil of gray-forest-meadow type in the Sheki stronghold. 10 plants were selected from each experiment. Plant growth was measured every 15 days. After drying the collected leaves in the Rolla and Decloit drying chambers, the mass of dry leaves was determined. Due to the biological properties of Virginia tobacco varieties group, nitrogen (N) fertilization is not considered acceptable. For the first time in Azerbaijan, the effect of nitrogen fertilizers on the growth of tobacco variety Virginia Cocker 347 under irrigation conditions was studied. According to the results of the study in the growing season of 2020, it was found that the highest growth dynamics among the variants was obtained against the background of N45P120 + 20 tons and manure on an area of 90×40 cm. 70-80-50% of the irrigation rate was 253.4 cm, 70-80-60% of the irrigation rate 255.1 cm, 70-70-60% of the irrigation rate 251.4 cm. 27.7 hwt/ha when irrigated at 70-70-60%.

Effects of Microplastics on Growth and Physiological Characteristics of Tobacco (Nicotiana tabacum L.)

The environmental effects caused by the proliferation of microplastics have received extensive attention. However, at this stage, there is a lack of research on the toxicology of microplastics and their impacts on plants. This study explored the effects of microplastics on the growth and physiological characteristics of tobacco. Using tobacco (Nicotiana tabacum L.) variety Yunyan87 and low-density polyethylene (LDPE, 13 μm particle size), different concentrations, which were 0 mg/L (CK), 10 mg/L (T1), 100 mg/L (T2), and 1000 mg/L (T3), were subjected to hydroponic experiments to study the effects of microplastics on the growth and physiological characteristics of tobacco. The results showed that microplastics had a certain inhibitory effect on the growth of tobacco. Among them, high concentrations of microplastics significantly inhibited the root architecture and growth characteristics. According to the performance observed with different treatments, the content of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) increased in the medium and high concentrations. In addition, the changes in catalase (CAT) and peroxidase (POD) activity were not obvious. Experiments showed that microplastics could significantly inhibit the growth and development of tobacco and reduce the accumulation of aerial parts and root biomass.

Quality Parameters as Influenced by Different Integrated Nutrient Management of Rustica Tobacco (Nicotiana rustica L.) and Its Residual Impact on Succeeding Summer Green Gram (Vigna radiata L.)

The present research work entitled “Quality parameters as influenced by different integrated nutrient management of rustica tobacco (Nicotiana rustica L.) and its residual impact on succeeding summer green gram (Vigna radiata L.) ” a field experiment was conducted during rabi and summer season of years 2020-21 and 2021-22 at Bidi Tobacco Research Station, Anand Agricultural University, Anand, Gujarat. The experimental field had an even topography with a gentle slope having good drainage and sandy loam in texture. The soil of the experimental field at 0-15 cm depth was low in organic carbon and available nitrogen, medium in available phosphorus and potassium and slightly alkaline in reaction. The ten integrated nutrient management treatments viz., T1: 100% RDF (200-00-00 kg/ha), T2: 75% RDF + 25% N from FYM, T3: 75% RDF + 25% N from poultry manure, T4: 75% RDF + 25% N from castor cake, T5: 50% RDF + 50% N from FYM, T6: 50% RDF + 50% N from poultry manure, T7: 50% RDF + 50% N from castor cake, T8: 50% RDF + 25% N from FYM + Azotobacter, T9: 50% RDF + 25% N from poultry manure + Azotobacter, T10: 50% RDF + 25% N from castor cake + Azotobacter were tested in Randomized Block Design with four replications. Rustica tobacco variety GCT 3 was considered as main rabi crop and green gram variety GAM 5 was considered as summer residual crop. The experiment was conducted on the same site during both the years without changing randomization of treatments. Results of the experiment showed that quality parameters viz. nicotine content was found significant due to various integrated nutrient management during both the years (2020-21 and 2021-22) in pooled analysis, while reducing sugar and chloride content was found non-significant during both the years (2020-21 and 2021-22) but significant result was observed in pooled analysis due different integrated nutrient management in both quality parameters under application of 75% RDF + 25% N from poultry manure (T3). In case of residual summer green gram protein content in seed and protein yield exerted significant result due to various integrated nutrient management during the years 2021, 2022 and in pooled analysis under application of 50% RDF + 50% N from FYM (T5). Interaction effect (Y x T) was found non-significant on all the growth parameters during the experiment.

Creation of High-yielding, High-quality, Resistant to Diseases and Pests Varieties of Nicotiana tabacumin the Zakatala District (Azerbaijan)

The article is devoted to the study, creation of high-yielding, high-quality and disease-resistant varieties of tobacco. The basis for obtaining stable and high yields of such high-quality raw materials is the selection of appropriate varieties of tobacco for various agro-economic conditions. For the first time, studies have been carried out on the effect of fertilizers and previous crops on the yield and quality of aromatic varieties of tobacco.

CONSUMPTION PATTERNS OF TOBACCO AND INTOXICANTS IN INDIA

Tobacco smoking and binge alcohol drinking are two of the leading risk factors for premature mortality worldwide. In India, studies have examined the geographic distributions of tobacco smoking and alcohol drinking only at the state-level; sub-state variations and the spatial association between the two consumptions are poorly understood. We analyze the consumption patterns, socio-economic distribution and the household choice of a variety of harmful tobacco and alcohol products across India.

Affordable phosphor-converted LEDs with specific light quality facilitate the tobacco seedling growth with low energy consumption in Industrial Seedling Raising.

Industrial Seedling Raising (ISR) is increasingly becoming an important part of Modern Agriculture because of its efficient utilization of land, water, and fertilizer as well as its advantages of being not easily affected by the weather. However, the high cost and high energy consumption of light sources for plant growth is limiting the popularization of ISR technology. Phosphor-converted light-emitting diodes (pc-LEDs) make use of relatively affordable red phosphor and blue light chips, providing an adjustable spectrum to optimize plant growth. To identify the energy-saving light quality of pc-LEDs, we investigated the effects of a variety of light qualities on the growth of tobacco seedlings. Y3Al5O12:Ce3+, CaAlSiN3:Eu2+, KAl11O17:Eu2+ phosphors were combined with the blue light chip according to different proportions to produce the following light sources: CK (white light), T1 (blue light), T2 (red light), T3 (red: blue light ratio=1:4), T4 (red: blue light ratio=4:1). The tobacco variety Xiangyan7 grown continuously under T1, T2, T3, and T4 significantly increased the leaf area, stem length, biomass, root area and main root length compared with those grown under white light. Among the five kinds of light qualities tested, T4 treatment exerted the best effect on leaf development and biomass increase, while T2 exerted the best effect on stem elongation. The cytological analysis demonstrated that the promotion of the cell size and cell number of leaf epidermal cells by T1-T4 might contribute to the leaf expansion. Further analysis at the molecular level suggested that the light quality affected the RNA levels of the genes involved in cell division and expansion. When tobacco seedlings reached the same biomass, T1-T4 light sources saved 71%, 86%, 80% and 89% of electric energy respectively compared with white light. Therefore, the application of specific pc-LEDs not only reduces the cost of light source production, but also saves energy consumption, offering great potential for ISR technology to cut costs and increase efficiency.

Nitrogen metabolic rate and differential ammonia volatilization regulate resistance against opportunistic fungus Alternaria alternata in tobacco.

Nutritional correlations between plants and pathogens can crucially affect disease severity. As an essential macronutrient, the availability of nitrogen (N) and the types of N content play a fundamental part not only in energy metabolism and protein synthesis but also in pathogenesis. However, a direct connection has not yet been established between differences in the level of resistance and N metabolism. Pertinently, former studies hold ammonia (NH3) accountable for the development of diseases in tobacco (Nicotiana tabacum L.) and in some post-harvest fruits. With a purpose of pinpointing the function of NH3 volatilization on Alternaria alternata (Fries) Keissl pathogenesis and its correlation with both N metabolism and resistance differences to Alternaria alternata infection in tobacco, leaf tissue of two tobacco cultivars with susceptibility (Changbohuang; CBH), or resistance (Jingyehuang; JYH) were analyzed apropos of ammonia compensation point, apoplastic NH4+ concentration, pH value as well as activities of key enzymes and N status. At the leaf age of 40 to 60 d, the susceptible cultivar had a significantly higher foliar apoplastic ammonium (NH4+) concentration, pH value and NH3 volatilization potential compared to the resistant one accompanied by a significant reduction in glutamine synthetase (GS), which in particular was a primary factor causing the NH3 volatilization. The NH4+ concentration in CBH was 1.44 times higher than that in JYH, and CBH had NH3 compensation points that were 7.09, 6.15 and 4.35-fold higher than those of JYH at 40, 50 and 60 d, respectively. Moreover, the glutamate dehydrogenase (GDH) activity had an upward tendency related to an increased NH4+ accumulation in both leaf tissues and apoplast but not with the NH3 compensation point. Collectively, our results strongly suggest that the accumulation of NH3 volatilization, rather than NH4+ and total N, was the primary factor inducing the Alternaria alternata infection in tobacco. Meanwhile, the susceptible cultivar was characterized by a higher N re-transfer ability of NH3 volatilization, in contrast to the disease–resistant cultivar, and had a stronger capability of N assimilation and reutilization. This study provides a deeper understanding of the pathogenicity mechanism induced by Alternaria alternata, which is useful for breeding Alternaria alternata-resistant varieties of tobacco, at the same time, our research is also conducive to control tobacco brown spot caused by Alternaria alternata in the field.