Project description:The saprotrophic fungus P. citrinum is a dorminant leaf-degrading fungus in tobacco industry. The genome-wide exprssion analysis involved in fungal growth was analyzed by using high throughput sequencing (RNA-Seq) on two substrates and time points. Our transcriptional profiles revealed that numerous differentially expressed genes (DEGs), of which involved in metabolism, cell transport and cell rescue, were significantly involved in tobacco-degradation process of P. citrinum.
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 (Nicotiana tabacum L.) is an important cash crop, and the size of its leaves significantly influences both yield and quality. However, the upper part of tobacco leaves, due to its dense tissue structure, often faces issues such as narrow and thick leaves during the production of roasted cigarettes. These problems have a severe impact on the yield and quality of the upper leaf. Although the mechanism of leaf size regulation in Arabidopsis thaliana has been extensively studied, it remains unclear for tobacco. Therefore, this research aimed to investigate the role of the NtAN3 gene in regulating tobacco leaf size by utilizing the NC82 variety. The researchers created both an overexpression mutant (G27) and a silencing mutant (M21) of the NtAN3 gene and examined their impact on leaf size using cell morphology observation and transcriptome analysis. These research findings offer valuable insights for molecular breeding aimed at improving tobacco yield and enhancing the availability of upper leaves.
Project description: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.
Project description:We identified NtCISZOG as a key regulator of chlorophyll content in tobacco, revealing its interaction with NtChlH, which provides a genetic basis for breeding tobacco varieties with centralized leaf maturation.
Project description:For decades the tobacco plant has served as a model organism in plant biology to answer fundamental biological questions in the areas of plant development, physiology, and genetics. Due to the lack of sufficient coverage of genomic sequences, however, none of the expressed sequence tag (EST)-based chips developed to date cover gene expression from the whole genome. The availability of Tobacco Genome Initiative (TGI) sequences provides a useful resource to build a whole genome exon array, even if the assembled sequences are highly fragmented. Here, the design of a Tobacco Exon Array is reported and an application to improve the understanding of genes regulated by cadmium (Cd) in tobacco is described. From the analysis and annotation of the 1,271,256 Nicotiana tabacum fasta and quality files from methyl filtered genomic survey sequences (GSS) obtained from the TGI and ~56,000 ESTs available in public databases, an exon array with 272,342 probesets was designed (four probes per exon) and tested on two selected tobacco varieties. Two tobacco varieties out of 45 accumulating low and high cadmium in leaf were identified based on the GGE biplot analysis, which is analysis of the genotype main effect (G) plus analysis of the genotype by environment interaction (GE) of eight field trials (four fields over two years) showing reproducibility across the trials. The selected varieties were grown under greenhouse conditions in two different soils and subjected to exon array analyses using root and leaf tissue to understand the genetic make-up of the Cd accumulation. An Affymetrix Exon Array was developed to cover a large (~90%) proportion of the tobacco gene space. The Tobacco Exon Array will be available for research use through the Affymetrix array catalogue. As a proof of the exon array usability, we have demonstrated that the Tobacco Exon Array is a valuable tool for studying Cd accumulation in tobacco leaves. Data from field and greenhouse experiments supported by gene expression studies strongly suggested that the difference in leaf Cd accumulation between the two specific tobacco cultivars is dependent solely on genetic factors and genetic variability rather than on the environment.
Project description:Diterpenoids and sucrose esters are synthesized in cigar tobacco leave (CTLs) trichomes and secreted onto leaf surface as trichome exudate (TE), contributing to sensory quality.To reveal the mechanism by which TE affects CTLs quality, this study employed the half-leaf method, utilizing tobacco extract as the fermentation medium for cigar tobacco leaves. We analyze the effects of TE on the sensory quality, chemical composition, and microbial communities of cigar tobacco leaves. The levels of degradation products (solanone, isovaleric acid, sclareolide, and sclareol) in the trichome exudate increased, while the levels of reducing sugars, proteins, and tobacco alkaloids decreased. These chemical changes are key factors in enhancing the aroma of smoke, increasing sweetness, reducing harshness, and lowering physiological strength. Metabolic alterations in tobacco leaves led to significantly increased levels of lipids and lipoids, organic acids and their derivatives, and organic heterocyclic compounds. TE enriches Pseudomonas aff. cichorii and Aspergillus aff. intermedius, which degrade nicotine and protein, increase the contents of reducing sugars, amino acids, lipids and lipid-like molucules. This reduces the irritation and physiological strength of CTLs and enhances the sweet taste. Meanwhile, TE is degraded and transformed by P. aff. cichorii to generate aroma compounds, thereby enhancing the aroma quality of cigar tobacco leaves.This study demonstrated that TE not only provides aroma precursors but also modifies leaf chemical components by shaping the microbial community during fermentation, thereby improving CTLs quality and providing a theoretical basis for establishing an artificial fermentation technology system for CTLs based on TE.
Project description:We used two hybrid combinations and their 4 parents as materials. One week after topping the tobacco plant, samples were taken, including three tissues: root, stalk, and leaf. The RNA of these samples was extracted, and transcriptome sequencing analysis was carried out to explore the transcriptional profile differences between hybrids and their parents, and to analyze the gene differential expression between different tissues.