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- Tobacco-Smoking-Related Differential DNA Methylation: 27K Discovery and Replication(The American Journal of Human Genetics, 2011) Lutz P. BreitlingTobacco smoking is responsible for substantial morbidity and mortality worldwide, in particular through cardiovascular, pulmonary, and malignant pathology. CpG methylation might plausibly play a role in a variety of smoking-related phenomena, as suggested by candidate gene promoter or global methylation studies. Arrays allowing hypothesis-free searches on a scale resembling genome-wide studies of SNPs have become available only very recently. Methylation extents in peripheral-blood DNA were assessed at 27,578 sites in more than 14,000 gene promoter regions in 177 current smokers, former smokers, and those who had never smoked, with the use of the Illumina Human Methylation 27KBeadChip.Thisrevealeda single locus, cg03636183, located in F2RL3, with genome-wide significance for lower methylation in smokers (p ¼ 2.68 3 10 31). This was similarly significant in 316 independent replication samples analyzed by mass spectrometry and Sequenom EpiTyper (p ¼ 6.33 3 10 34). Our results, which were based on a rigorous replication approach, show that the gene coding for a potential drug target of cardiovascular importance features altered methylation patterns in smokers. To date, this gene had not attracted attention in the literature on smoking.
- Linalool Induces Resistance Against Tobacco Mosaic Virus in Tobacco Plants(Plant Disease, 2023) He YanThe essential oil of Cinnamomum camphora is the most widely consumed and used spice in the world today. It has therapeutic effects in medicine and has been shown to have good antibacterial and bacterio static effects in agriculture. This study found that C. camphora oil significantly induced plant disease resistance activity. Linalool, its main active component, significantly induced plant disease resistance activity (67.49% at a concentration of 800 pg/ml) over the same concentration of the chitosan oligosaccharide positive control but had no direct effect on tobacco mosaic virus (TMV). In this study of its antiviral mechanism, linalool induced hypersensitive reaction (HR); the overexpression of related defense enzymes SOD, CAT, POD, and PAL; and the accumulation of H2O2 and SA content in N. glutinosa. Besides, linalool induced crops resistance against Colletotrichum lagenarium, Botrytis cinerea, Sclerotinia sclerotiorum, and Phytophthora capsica. Taken together, the anti-TMV mechanism of linalool involved the induction of plant disease resistance through activation of a plant immune response mediated by salicylic acid. Linalool-induced plant disease resistance activity has a long duration, broad spectrum, and rich resources; linalool thus has the potential to be developed as a new plant-derived antiviral agent and plant immune activator.
- Controlling Tobacco Diseases: An Overview of Black Shank and Fusarium Wilt(International Journal of Applied Sciences and Biotechnology, 2023) Roman PandeyBlack shank, caused by Phytophthora nicotianae, and Fusarium wilt, caused by the Fusarium oxysporium f. sp. nicotianae, are major diseases affecting tobacco crops globally. Phytophthora nicotianae is primarily found in tropical and subtropical regions and infects tobacco plants by producing zoospores that swim to root tissue and form cysts. Symptoms of black shank include root and crown rot, wilting, leaf chlorosis, stem lesions, and pith necrosis. Management strategies for black shank include cultural practices, chemical treatments, and host resistance. Chemical fungicides, such as metalaxyl or mefenoxam, oxathiapiprolin, and fluopicolide, can be used but there is a risk of fungicide resistance. Fusarium wilt is characterized by yellowing, drying, and death of leaves, leading to the death of the entire plant. Control measures for Fusarium wilt include plant resistance, cleanliness, crop rotation, nutrition, nematode management, and fumigation or biofumigation. The most successful control of Fusarium wilt has been through the use of resistant tobacco cultivars. The impact of rotation crops and resistant plants on the pathogen populations in the soil must be evaluated and soil pH and calcium levels may also impact the disease. The presence of the fungus in a field can last for several years without a vulnerable host.
- Carbohydrates—Key Players in Tobacco Aroma Formation and Quality Determination(MDPI, 2020)Carbohydrates are important compounds in natural products where they primarily serve as a source of energy, but they have important secondary roles as precursors of aroma or bioactive compounds. They are present in fresh and dried (cured) tobacco leaves as well. The sugar content of tobacco depends on the tobacco variety, harvesting, and primarily on the curing conditions (temperature, time and moisture). If the process of curing employs high temperatures (flue-curing and sun-curing), final sugar content is high. In contrast, when air curing has a lower temperature, at the end of the process, sugar level is low. Beside simple sugars, other carbohydrates reported in tobacco are oligosaccharides, cellulose, starch, and pectin. Degradation of polysaccharides results in a higher yield of simple sugars, but at the same time reduces sugars oxidization and transfer into carbon dioxide and water. Loss of sugar producers will compensate with added sugars, to cover undesirable aroma properties and achieve a better, pleasant taste during smoking. However, tobacco carbohydrates can be precursors for many harmful compounds, including formaldehyde and 5-hydroxymethylfurfural. Keeping in mind that added sugars in tobacco production are unavoidable, it is important to understand all changes in carbohydrates from harvesting to consuming in order to achieve better product properties and avoid the formation of harmful compounds. This review summarizes current knowledge about tobacco carbohydrates, including changes during processing with special focus on carbohydrates as precursors of harmful compounds during smoking.
- Chemical Basis of the Fungicidal Activity of Tobacco Extracts against Valsa mali(MDPI, 2016) Zhongfeng ZhangUnder pressure from social criticism and an unclear future, tobacco researchers have begun to seek alternative uses for the product. Here, we present our study on isolating tobacco compounds with fungicidal activity, which could be used as plant-derived pesticides. Using Valsa mali as the target fungus, agar plate tests were conducted to evaluate the fungicidal activity of various tobacco extracts, including tobacco leaves extracts prepared with different solvents, extracts of different tobacco cultivars, and samples from different tobacco organs. Fungal growth morphology was used as the criterion to evaluate the fungicidal activity of tobacco extracts. Correlation analyses between the fungicidal activities and the chemical components of tobacco extracts indicated the major chemical constituents with fungicidal activity. Then, the active compounds were isolated and their effects on the ultra-microstructures of V. mali was analyzed using scanning- and transmission-electron microscopy. The results suggested that tobacco extracts prepared with solvents of weaker polarity had higher fungicidal activity, and the inhibitory activity of tobacco extracts against V. mali was also cultivar dependent. Furthermore, the fungicidal effects of tobacco flower extracts were higher than those of the leaf extracts. Chemical analysis indicated that cembranoids were the main fungicidal substances, which act by destroying the endometrial structure of the fungus. Tobacco cembranoids at 80 µg/mL could completely inhibit the growth of V. mali, with an EC50 value of 13.18 µg/mL. Our study therefore suggests that tobacco leaves and inflorescences are excellent plant resources for the biological control of V. mali.