Project description:Comparative analysis of tobacco leaves transcriptomes unveils carotenoid pathway potentially determined the characteristics of aroma compounds in different environmental regions. Tobacco (Nicotiana tabacum) is a sensitive crop to environmental changes, and a tobacco with unique volatile aroma fractions always formed in specific ecological conditions. In order to investigate the differential expressed genes caused by environmental changes and reveal the formation mechanism of characteristics of tobacco in three different aroma tobacco regions of Guizhou Province, Agilent tobacco microarray was adapted for transcriptome comparison of tobacco leaves in medium aroma tobacco region Kaiyang and light aroma tobacco regions Weining and Tianzhu. Results showed that there was big difference among the gene expression profiles of tobacco leaves in different environmental conditions. A total of 517 differential expressed genes (DEGs) between Weining and Tianzhu were identified, while 733 and 1,005 genes differentially expressed between Longgang and another two tobacco regions Weining and Tianzhu, respectively. Compared with Longgang, up-regulated genes in Weining and Tianzhu were likely involved in secondary metabolism pathways, especially carotenoid pathway, including PHYTOENE SYNTHASE, PHYTOENE DEHYDROGENASE, LYCOPENE ε-CYCLASE, CAROTENOID β-HYDROXYLASE and CAROTENOID CLEAVAGE DIOXYGENASE 1 genes, while most down-regulated genes played important roles in response to temperature and light radiation, such as heat shock proteins. Gene Ontology and MapMan analyses demonstrated that the DEGs among different environmental regions were significantly enriched in light reaction of photosystem II, response of stimulus and secondary metabolism, suggesting they played crucial roles in environmental adaptation and accumulation of aroma compounds in tobacco plants. Through comprehensive transcriptome comparison, we not only identified several stress response genes in tobacco leaves from different environmental regions but also highlighted the importance of carotenoid pathway genes for characteristics of aroma compounds in specific growing regions. Our study primarily laid the foundation for further understanding the molecular mechanism of environmental adaptation of tobacco plants and molecular regulation of aroma substances in tobacco leaves.
Project description:Alternations in gene methylation and other epigenetic changes regulate normal development as well as drive disease progression. Chronic cigarette smoking causes hyper- and hypo-methylation of genes that could contribute to smoking-related diseases. It is unclear whether consumers of non-combustible tobacco, such as moist snuff, also exhibit such perturbations in their methylome. Here, we present global methylation changes relative to non-tobacco consumers in buccal cells collected from smokers (SMK) and moist snuff consumers (MSC). Generally healthy adult male study subjects were recruited into SMK, MSC and Non-Tobacco Consumer (NTC) cohorts (40 subjects/cohort). Global methylation profiling was performed on the Illumina 450K methylation array using buccal cell DNA. A total of 1,252 loci were found to be significantly differentially methylated in tobacco consumers relative to non-tobacco consumers. Overall, the SMK cohort exhibited larger qualitative and quantitative changes relative to MSC. Approximately half of the total number of gene loci, classified as Combustible Tobacco-Related signatures, and a third of the changes, termed Tobacco-Related signatures, were commonly detected in the tobacco consumers. Very few differences were detected between MSC and NTC, and hierarchical clustering of the top 50 significant gene loci suggested that MSC and NTC co-cluster. Consistent with physiological functions of AhR, combustible tobacco drives profound changes in buccal cell methylation status, principally impacting cell development and immune response pathways. These results aid in placing combustible and non-combustible tobacco products along a risk continuum and provide additional insights into the effects of tobacco consumption.
Project description:The degree of yellowing in tobacco leaves is an important indicator for determining the maturity and harvesting time of tobacco leaves. Reduction in chlorophyll is of utility for promoting the concentrated maturation of tobacco leaves and achieving mechanised harvesting and mining, and utilising tobacco yellow leaf regulatory genes is of great significance for the selection and breeding of tobacco varieties suitable for mechanised harvesting and the resolution of the molecular mechanisms controlling leaf colouration. In this study, the phenotypes of the yellow-leaf K326 and K326 varieties were analysed, and it was observed that the yellow-leaf K326 variety exhibited a distinct yellow leaf phenotype with a significant reduction in chlorophyll content. Subsequently, using a combination of BSA-seq, transcriptomic sequencing (RNA-seq), and proteomic sequencing approaches, we identified the candidate gene Nitab4.5_0008674g0010 that encodes dihydroneopterin aldolase as a factor associated with tobacco leaf yellowing. Finally, by measuring the folate content in K326 and Huangye K326, the folate content in Huangye K326 was observed to be significantly lower than that in K326, thus indicating that folate synthesis plays a crucial role in phenotypic changes in tobacco yellow leaves. This study is the first to use BSA-seq combined with RNA-seq and proteomic sequencing to identify candidate genes in tobacco yellow leaves. The results provide a theoretical basis for the analysis of the mechanism of tobacco yellow leaf mutations.
Project description:Tobacco in its smoke and smokeless form are major risk factors for ESCC (esophageal squamous cell carcinoma). However, molecular alterations associated with smokeless tobacco exposure are poorly understood. In the Indian subcontinent, tobacco is predominantly consumed in chewing form. An understanding of molecular alterations associated with chewing tobacco exposure is vital for identifying molecular markers and potential targets. We developed an in-vitro cellular model by exposing non-transformed esophageal epithelial cells to chewing tobacco over eight month period. Chronic exposure to chewing tobacco led to increase in cell proliferation, invasive ability and anchorage independent growth indicating cell transformation. Molecular alterations associated with chewing tobacco exposure were characterized by carrying out exome sequencing and quantitative proteomic profiling of parental cells and chewing tobacco exposed cells. Quantitative proteomic analysis revealed that established cancer stem cell markers are elevated in tobacco treated cells. Decreased expression of enzymes associated with the glycolytic pathway and increased expression of a large number of mitochondrially localized proteins involved in the electron transport chain as well as enzymes of TCA cycle were also identified. Electron micrographs revealed increase in number and size of mitochondria. Based on these observations, we hypothesise that chronic treatment of esophageal epithelial cells with tobacco leads to a cancer stem cell-like phenotype. These cells also show characteristic OXPHOS phenotype which can be potentially targeted as a therapeutic strategy.
Project description:To investigate the molecular mechanism of tobacco flower in response to the cold treatment, transcriptomic analysis was performed using Agilent Tobacco Gene Expression Microarrays.
Project description:Tobacco exposure has been established to be a major risk factor for developing oral squamous cell carcinoma (OSCC). The purpose of this study is to identify potential biomarkers to distinguish the biological effectsof combustible tobacco products from that of non-combustible tobacco products using normal human gingival epithelial cells (HGEC), non-metastatic (101A) and metastatic (101B) OSCC cell lines.
Project description:Tobacco is mainly consumed in two different forms (smoking and chewing) that vary in their composition and methods of intake. Despite being the leading cause of oral cancer, the molecular mechanisms resulting in malignancy upon tobacco exposure are yet to be fully elucidated. We therefore sought to compare the molecular alterations in oral keratinocytes exposed to smoke and chewing tobacco. OKF6/TERT1 cells were exposed to cigarette smoke condensate or chewing tobacco for progressively increasing durations (2, 4, 6 and 8 months). We employed a TMT-based quantitative proteomics approach to investigate the adverse effects of chronic cigarette smoke or chewing tobacco exposure in oral keratinocytes. LC/MS3 analysis resulted in the quantification of 5,342 proteins and 2,821 proteins in cigarette smoke and chewing tobacco exposed cells, respectively. Upstream regulator analysis indicates the involvement of distinct regulators in CSC exposed cells compared to STE exposed cells. In addition, exome sequencing revealed discrete genetic alterations in cells exposed to each insult. Current analysis defines a clear distinction in the molecular dysregulation in oral cells in response to different tobacco-based insults. Some of the proteins dysregulated in cigarette smoke or chewing tobacco exposed cells may serve as potential early detection biomarkers which could aid in stratification of patients based on tobacco usage history.