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:sua-CMS (cytoplasmic male sterility) is the only male sterile system in tobacco breeding, but the mechanism of abortion is unclear. Cytological characteristics show that abortion in the sua-CMS line msZY occurs before the differentiation of sporogenous cells. In this study, a comparative transcriptomic analysis was conducted on flower buds at the abortion stage of msZY and its male fertile control ZY. A total of 462 differentially expressed genes were identified in msZY and ZY, which were enriched via protein processing in the endoplasmic reticulum (ER), oxidative phosphorylation, photosynthesis, and circadian rhythm-plant by Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. Most genes were downregulated in the ER stress pathway, heat-shock protein family, F1F0-ATPase encoding by the mitochondrial genome, and differentiation of stamens. Genes in the programmed cell death (PCD) pathway were upregulated in msZY. The transcriptome results were consistent with those of qRT-PCR. Ultrastructural and physiological analyses indicted active vacuole PCD and low ATP content in msZY young flower buds. We speculated that PCD and a deficiency in ATP synthesis are essential for the abortion of sua-CMS. This study reveals the potential mechanism of abortion of tobacco sua-CMS.
Project description:The development of low-alkaloid (LA) tobacco varieties is an important target in the tobacco breeding industry. However, LA Burley 21 plants, in which the Nic1 and Nic2 loci controlling nicotine biosynthesis are deleted, are characterized by impaired leaf maturation that leads to poor leaf quality before and after curing. Polyamines are involved in key developmental, physiological, and metabolic processes in plants, and act as anti-senescence and anti-ripening regulators. We investigated the role of polyamines in tobacco leaf maturation by analyzing the free and conjugated polyamine fractions in the leaves and roots of four Burley 21 varieties: NA (normal alkaloid levels, wild-type control), HI (high intermediates, nic2 -), LI (low intermediates, nic1 -), and LA (nic1 - nic2 -). The pool of conjugated polyamines increased with plant age in the roots and leaves of all four varieties, but the levels of free and conjugated putrescine and spermidine were higher in the LI and LA plants than NA controls. The increase in the polyamine content correlated with delayed maturation and senescence, i.e., LA plants with the highest polyamine levels showed the most severe impaired leaf maturation phenotype, characterized by higher chlorophyll content and more mesophyll cells per unit leaf area. Treatment of LA plants with inhibitors of polyamine biosynthesis and/or the growth regulator Ethephon® reduced accumulation of polyamines, achieving a partial amelioration of the LA phenotype. Our data show that the regulation of polyamine homeostasis is strongly disrupted in LA plants, and that free and conjugated polyamines contribute to the observed impairment of leaf maturation.
Project description:Cutaneous malignant melanoma is an aggressive cancer of melanocytes with a strong propensity to metastasize. We posit that melanoma cells acquire metastatic capability by adopting an embryonic-like phenotype, and that a lineage approach would uncover metastatic melanoma biology. Using a genetically engineered mouse model to generate a rich melanoblast transcriptome dataset, we identify melanoblast-specific genes whose expression contribute to metastatic competence and derive a 43-gene signature that predicts patient survival. We identify a melanoblast gene, KDELR3, whose loss impairs experimental metastasis. In contrast, KDELR1 deficiency enhances metastasis, providing the first example of different disease etiologies within the KDELR-family of retrograde transporters. We show that KDELR3 regulates the metastasis suppressor, KAI1, and report an interaction with the E3 ubiquitin-protein ligase gp78, a regulator of KAI1 degradation. Our work demonstrates that the melanoblast transcriptome can be mined to uncover targetable pathways for melanoma therapy.
Project description:Plant growth, crop yield, and pest and disease control are enhanced by PGPR (Plant growth promoting rhizobacteria), which are beneficial microorganisms found in a close symbiosis with plant roots. Phytohormones are secreted, nutrient uptake is improved, and soil properties along with the microbiological environment are regulated by these microorganisms, making them a significant focus in agricultural research. In this study, the efficient PGPR strain T1 was isolated and screened from tobacco inter-root soil, and identified and confirmed by ITS sequencing technology. Tobacco growth indicators and soil property changes were observed and recorded through potting experiments. The activities of key enzymes (e.g., sucrase, catalase, urease) in soil were further determined. High-throughput sequencing technology was utilized to sequence the soil microbial community, and combined with macro-genomics analysis, the effects of T1 strain on soil microbial diversity and metabolic pathways were explored. Following the application of T1, significant improvements were observed in the height, leaf length, and width of tobacco plants. Furthermore, the physical and chemical properties of the soil were notably enhanced, including a 26.26% increase in phosphorus availability. Additionally, the activities of key soil enzymes such as sucrase, catalase, and urease were significantly increased, indicating improved soil health and fertility. Comprehensive joint microbiomics and macrogenomics analyses revealed a substantial rise in the populations of beneficial soil microorganisms and an enhancement in metabolic pathways, including amino acid metabolism, synthesis, and production of secondary metabolites. These increase in beneficial microorganisms and the enhancement of their metabolic functions are crucial for plant growth and soil fertility. This study provides valuable references for the development of innovative microbial fertilizers and offers programs for the sustainable development of modern agriculture.
Project description:Light/dark (L/D) cycle plays a crucial role in controlling the production and quality of vegetables. However, the mechanism of L/D cycle on vegetable growth and quality is scarce studied. To investigate the impact of L/D cycle on lettuce growth and quality, we designed three diel scenarios, including 16 hours of light and 8 hours of darkness (L16/D8), 12 hours of light and 6 hours of darkness (L12/D6), and 8 hours of light and 4 hours of darkness (L8/D4). By phenotypic analysis, we found that lettuce grew taller under the L8/D4 scenario than under L16/D8 light cycle scenarios. The physiological indexes showed that the lettuce leaves grown in the L8/D4 scenario exhibited greater enhancements in the levels of soluble protein, soluble sugar, and carotenoid content compared to the other scenarios. By comparing the expression levels under different diel scenarios (L16/D8 vs L12/D6, L16/D8 vs L8/D4, and L12/D6 vs L8/D4), we identified 7,209 differentially expressed genes (DEGs). Additionally, 3 gene modules that were closely related to L/D cycle of lettuce were selected by WGCNA analysis. The eigengenes of three gene modules were enriched in plant hormone signal transduction, sphingolipid metabolism, and nucleocytoplasmic transport pathways. Through network analysis, we identified six hub genes (CIP1, SCL34, ROPGEF1, ACD6, CcmB, and Rps4) in the three gene modules, which were dominant in plant circadian rhythms and greatly affected lettuce growth. qRT-PCR analysis confirmed the diurnal response patterns of the 6 hub genes in different treatments were significant. This study intensively enhanced our comprehension of the L/D cycle in the growth morphology, nutritional quality, and metabolic pathways of lettuce.
Project description:Rosa beggeriana 'Aurea' is a yellow-green leaf (yl) mutant and originated from Rosa beggeriana Schrenk by 60Co-γ irradiation, which is an important ornamental woody species. However, the molecular mechanism of the yl mutant remains unknown. Herein, comparative transcriptome profiling was performed between the yl type and normal green color type (WT) by RNA sequencing. A total of 3,372 significantly differentially expressed genes (DEGs) were identified, consisting of 1,585 upregulated genes and 1,787 downregulated genes. Genes that took part in metabolic of biological process (1,090), membrane of cellular component (728), catalytic (1,114), and binding of molecular function (840) were significantly different in transcription level. DEGs involved in chlorophyll biosynthesis, carotenoids biosynthesis, cutin, suberine, wax biosynthesis, photosynthesis, chloroplast development, photosynthesis-antenna proteins, photosystem I (PSI) and photosystem II (PSII) components, CO2 fixation, ribosomal structure, and biogenesis related genes were downregulated. Meanwhile, linoleic acid metabolism, siroheme biosynthesis, and carbon source of pigments biosynthesis through methylerythritol 4-phosphate (MEP) pathways were upregulated. Moreover, a total of 147 putative transcription factors were signification different expression, involving NAC, WRKY, bHLH, MYB and AP2/ERF, C2H2, GRAS, and bZIP family gene. Our results showed that the disturbed pigments biosynthesis result in yl color by altering the ratio of chlorophylls and carotenoids in yl mutants. The yl mutants may evoke other metabolic pathways to compensate for the photodamage caused by the insufficient structure and function of chloroplasts, such as enhanced MEP pathways and linoleic acid metabolism against oxidative stress. This research can provide a reference for the application of leaf color mutants in the future.
Project description:Leaf senescence, a pivotal process in plants, directly influences both crop yield and nutritional quality. Foxtail millet (Setaria italica) is a C4 model crop renowned for its exceptional nutritional value and stress tolerance characteristics. However, there is a lack of research on the identification of senescence-associated genes (SAGs) and the underlying molecular regulatory mechanisms governing this process. In this study, a dark-induced senescence (DIS) experimental system was applied to investigate the extensive physiological and transcriptomic changes in two foxtail millet varieties with different degrees of leaf senescence. The physiological and biochemical indices revealed that the light senescence (LS) variety exhibited a delayed senescence phenotype, whereas the severe senescence (SS) variety exhibited an accelerated senescence phenotype. The most evident differences in gene expression profiles between these two varieties during DIS included photosynthesis, chlorophyll, and lipid metabolism. Comparative transcriptome analysis further revealed a significant up-regulation of genes related to polysaccharide and calcium ion binding, nitrogen utilization, defense response, and malate metabolism in LS. In contrast, the expression of genes associated with redox homeostasis, carbohydrate metabolism, lipid homeostasis, and hormone signaling was significantly altered in SS. Through WGCNA and RT-qPCR analyses, we identified three SAGs that exhibit potential negative regulation towards dark-induced leaf senescence in foxtail millet. This study establishes the foundation for a further comprehensive examination of the regulatory network governing leaf senescence and provides potential genetic resources for manipulating senescence in foxtail millet.
Project description:Seed germination marks a new life cycle of a plant. Although ethylene promotes seed germination, the underlying molecular mechanism is poorly understood. Ethylene Responsive Factors (ERFs) play an essential role in ethylene signaling. Here we show that overexpression of Tomato Ethylene Responsive Factor 1 (TERF1), an ERF transcription factor isolated from tomato, can promote tobacco seed germination at 23 °C in darkness. Hormones analysis showed that salicylic acid (SA), 3-indoleacetic acid (IAA), abscisic acid (ABA) and gibberellic acids (GAs) were significantly increased by TERF1, while jasmonic acid (JA) was significantly reduced in TERF1 seeds. Transcriptome analysis identified 7,961 differentially expressed genes (DEGs), including 6,213 mRNAs, 25 miRNAs, 1,581 lncRNAs and 141 circRNAs. Gene Ontology (GO) enrichment analysis showed that cell cycles, sugar metabolism, microtubule-based processes were activated by TERF1, while DNA repair, lipid metabolism were repressed by TERF1. We also identified differentially expressed regulatory genes for ABA and GA biosynthesis or signaling in TERF1 seed, including transcription factors, kinases, phosphatases and ubiquitin protein ligases, non-coding RNAs (ncRNAs). At posttranscriptional level TERF1 also regulates gene expression through alternative splicing (AS). Protein-protein interaction (PPI) network analysis revealed three key biological processes regulated by TERF1, including nitrogen metabolism, light related processes and mitosis. Pheynotype and gene expression analysis showed that TERF1 significantly reduced seed sensitivity to ABA and auxin during germination through repressing key components of ABA signaling pathway. Our results unraveled the function of TERF1 in promoting seed germination.Supplementary informationThe online version contains supplementary material available at 10.1007/s12298-021-01049-4.