Purine metabolism in mesophyll protoplasts of tobacco (Nicotiana tabacum) leaves.
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ABSTRACT:
SUBMITTER: Barankiewicz J
PROVIDER: S-EPMC1161536 | biostudies-other | 1980 Jan
REPOSITORIES: biostudies-other
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Project description:Tobacco wildfire disease caused by Pseudomonas syringae pv. tabaci is one of the most destructive foliar bacterial diseases occurring worldwide. However, the effect of wildfire disease on cigar tobacco leaves has not been clarified in detail. In this study, the differences in microbiota and chemical factors between wildfire disease-infected leaves and healthy leaves were characterized using high-throughput Illumina sequencing and a continuous-flow analytical system, respectively. The results demonstrated significant alterations in the structure of the phyllosphere microbial community in response to wildfire disease, and the infection of P. syringae pv. tabaci led to a decrease in bacterial richness and diversity. Furthermore, the content of nicotine, protein, total nitrogen, and Cl- in diseased leaves significantly increased by 47.86%, 17.46%, 20.08%, and 72.77% in comparison to healthy leaves, while the levels of total sugar and reducing sugar decreased by 59.59% and 70.0%, respectively. Notably, the wildfire disease had little effect on the content of starch and K+. Redundancy analysis revealed that Pseudomonas, Staphylococcus, Cladosporium, and Wallemia displayed positive correlations with nicotine, protein, total nitrogen, Cl- and K+ contents, while Pantoea, Erwinia, Sphingomonas, Terrisporobacter, Aspergillus, Alternaria, Sampaiozyma, and Didymella displayed positive correlations with total sugar and reducing sugar contents. Brevibacterium, Brachybacterium, and Janibacter were found to be enriched in diseased leaves, suggesting their potential role in disease suppression. Co-occurrence network analysis indicated that positive correlations were prevalent in microbial networks, and the bacterial network of healthy tobacco leaves exhibited greater complexity compared to diseased tobacco leaves. This study revealed the impact of wildfire disease on the microbial community and chemical compositions of tobacco leaves and provides new insights for the biological control of tobacco wildfire disease.
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Project description:Withering is an important biological process associated with dehydration and cell wall metabolism in postharvest plant organs during curing/processing and storage. However, the withering mechanisms involved in dehydration and cell wall metabolism in postharvest tobacco leaves remain elusive. Here, TMT-based quantitative proteomic analysis in tobacco leaves under different withering conditions was performed. In total, 496 differentially abundant proteins (DAPs) were identified. To elucidate the withering mechanism of tobacco leaves, 28 DAPs associated with cell wall metabolism were screened.
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Project description:The growth and development of plants are sensitive to their surroundings. Although numerous studies have analyzed plant transcriptomic variation, few have quantified the effect of combinations of factors or identified factor-specific effects. In this study, we performed RNA sequencing (RNA-seq) analysis on tobacco leaves derived from 10 treatment combinations of three groups of ecological factors, i.e., climate factors (CFs), soil factors (SFs), and tillage factors (TFs). We detected 4980, 2916, and 1605 differentially expressed genes (DEGs) that were affected by CFs, SFs, and TFs, which included 2703, 768, and 507 specific and 703 common DEGs (simultaneously regulated by CFs, SFs, and TFs), respectively. GO and KEGG enrichment analyses showed that genes involved in abiotic stress responses and secondary metabolic pathways were overrepresented in the common and CF-specific DEGs. In addition, we noted enrichment in CF-specific DEGs related to the circadian rhythm, SF-specific DEGs involved in mineral nutrient absorption and transport, and SF- and TF-specific DEGs associated with photosynthesis. Based on these results, we propose a model that explains how plants adapt to various ecological factors at the transcriptomic level. Additionally, the identified DEGs lay the foundation for future investigations of stress resistance, circadian rhythm and photosynthesis in tobacco.
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Project description:To provide a detailed insight into the early biological process of tobacco mosaic disease, transcriptomic changes in tobacco leaves were surveyed at 1, 3 and 5 days after mono-infected by Tobacco mosaic virus (TMV) and co-infected by Cucumber mosaic virus (CMV) and TMV. At the three different stages, there were 2372, 3168 and 2045 differentially expressed genes (DEGs) in mono-infected leaves, and 2388, 3281 and 3417 DEGs were identified in co-infected leaves. There were 836, 1538 and 1185 common DEGs between the mono-infection and co-infection at the three time points, respectively. These common DEGs were enriched in the pathways, such as photosynthesis, biosynthesis of secondary metabolites, plant-pathogen interaction, porphyrin and chlorophyll metabolism, phenylalanine metabolism and phenylpropanoid biosynthesis. Photosynthesis pathway was observably down-regulated, and defense response pathways were markedly up-regulated. These pathways have been found to be related to tobacco mosaic disease. Of these common DEGs, the changes in expression of argonaute proteins, thioredoxins and peroxidases showed that the activation of RNA silencing and the destruction of redox balance can be induced by tobacco mosaic virus infection, resulting in the reset of biology process and damage in tobacco plants. Additionally, the occurrence of symptoms in co-infected tobacco plants was more early and serious than mono-infection, indicating that there is synergy between TMV and CMV in co-infected tobacco plants. The timely usage of antiviral agents and plant resistance inducers can decrease the incidence of tobacco mosaic disease through changing the expression of some DEGs, indicating that these genes can be used to screen novel plant resistance inducers and antiviral agents. Overall, our results were helpful in clarifying the mechanism of tobacco mosaic disease and provided novel strategies for the prevention of tobacco mosaic disease.
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Project description:An endophytic fungus Arthrinium arundinis TE-3 was isolated and purified from the fresh leaves of cultivated tobacco (Nicotiana tabacum L.). Chemical investigation on this fungal strain afforded three new prenylated diphenyl ethers (1-3) as well as three known analogues (4-6). Structure elucidation of the isolated compounds was carried out by analysis of 1D and 2D nuclear magnetic resonance (NMR) and high-resolution electrospray ionization mass spectroscopy (HRESIMS) spectra, as well as by comparison of those data with literature data. The absolute configuration of the stereogenic center at C-8 in 1 was assigned by comparison of the experimental and calculated ECD spectra. Compounds 1 and 2 showed selective antifungal activity against Mucor hiemalis with minimum inhibitory concentration (MIC) values of 8 and 4 μg/mL, respectively. Compounds 5 and 6 exhibited inhibitory activity against Alteraria alternata with an MIC value of 8 μg/mL. In the cytotoxic assay, 2, 5, and 6 displayed moderate in vitro cytotoxicity against the human monocytic cell line (THP-1 cell line), with IC50 values of 40.2, 28.3, and 25.9 μM, respectively. This study indicated that endophytic fungi possess great potential for exploring new bioactive secondary metabolites.
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Project description:BackgroundPollen tube growth is essential for plant reproduction and represents a widely employed model to investigate polarized cell expansion, a process important for plant morphogenesis and development. Cellular and regulatory mechanisms underlying pollen tube elongation are under intense investigation, which stands to greatly benefit from a comprehensive understanding of global gene expression profiles in pollen and pollen tubes. Here, RNA sequencing technology was applied to de novo assemble a Nicotiana tabacum male gametophytic transcriptome and to compare transcriptome profiles at two different stages of gametophyte development: mature pollen grains (MPG) and pollen tubes grown for six hours in vitro (PT6).ResultsDe novo assembly of data obtained by 454 sequencing of a normalized cDNA library representing tobacco pollen and pollen tube mRNA (pooled mRNA isolated from mature pollen grains [MPG] and from pollen tubes grown in vitro for 3 [PT3] or 6 [PT6] hours) resulted in the identification of 78,364 unigenes. Among these unigenes, which mapped to 24,933 entries in the Sol Genomics Network (SGN) N. tabacum unigene database, 24,672 were predicted to represent full length cDNAs. In addition, quantitative analyses of data obtained by Illumina sequencing of two separate non-normalized MPG and PT6 cDNA libraries showed that 8979 unigenes were differentially expressed (differentially expressed unigenes: DEGs) between these two developmental stages at a FDR q-value of <0.0001. Interestingly, whereas most of these DEGs were downregulated in PT6, the minor fraction of DEGs upregulated in PT6 was enriched for GO (gene ontology) functions in pollen tube growth or fertilization.ConclusionsA major output of our study is the development of two different high-quality databases representing the tobacco male gametophytic transcriptome and containing encompassing information about global changes in gene expression after pollen germination. Quantitative analyses of these databases 1) indicated that roughly 30% of all tobacco genes are expressed in the male gametophyte, and 2) support previous observations suggesting a global reduction of transcription after pollen germination. Interestingly, a small number of genes, many of which predicted to function in pollen tube growth or fertilization, were found to be upregulated in elongating pollen tubes despite globally reduced transcription.
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Project description:Genetic mapping of seed germination traits has been performed with many plant species. In tobacco, however, investigations are rare. In the present study, a bi-parental mapping population consisting of 118 doubled haploid lines and derived from a cross between 'Beinhart-1000' and 'Hicks' was investigated. Four germination-related traits, total germination (TG), normal germination (NG), time to reach 50% of total germination (T50), and the area under the curve after 200 h of germination (AUC) were considered by examining seeds either untreated or after a moderate controlled deterioration (CD). Quantitative trait loci were found for all traits distributed on 11 out of the 24 linkage groups. It was demonstrated that, as in many other species, germination-related traits are very complex and under polygenic control.
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