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The research interest in azulene‐embedded polycyclic aromatic hydrocarbons (PAHs) has significantly increased recently, but the lack of efficient synthetic strategies impedes the investigation of their structure‐property relationships and further opto‐electronic applications. Here we report a modular synthetic strategy towards diverse azulene‐embedded PAHs by a tandem Suzuki coupling and base‐promoted Knoevenagel‐type condensation with good yields and great structural versatility, including non‐alternant thiophene‐rich PAHs, butterfly‐ or Z‐shaped PAHs bearing two azulene units, and the first example of a two‐azulene‐embedded double [5]helicene. The structural topology, aromaticity and photophysical properties were investigated by NMR, X‐ray crystallography analysis and UV/Vis absorption spectroscopy assisted by DFT calculations. This strategy provides a new platform for rapidly synthesizing unexplored non‐alternant PAHs or even graphene nanoribbons with multiple azulene units. [ABSTRACT FROM AUTHOR]

Das Forschungsinteresse an in polyzyklische aromatische Kohlenwasserstoffe (PAKs) eingebettete Azulene hat sich in den letzten Jahren signifikant erhöht, aber der Mangel an effizienten Synthesestrategien hemmt die Studien der Struktur‐Eigenschaftsbeziehungen sowie weiterer opto‐elektronischer Anwendungen. Wir berichten hier von einer neuen modularen Synthesestrategie für diverse Azulen‐eingebettete PAKs durch eine Tandem Suzuki Kupplung und basenvermittelte Kondensation des knoevenagel Typs in guten Ausbeuten und exzellenter struktureller Vielfalt. Die Substrate beinhalten nicht‐alternierende thiophenreiche PAKs, schmetterlings‐ und z‐förmige PAKs mit zwei Azuleneinheiten sowie das erste Beispiel zweier eingebetteter Azuleneinheiten, welche ein doppel‐[5]Helicen bilden. Die strukturelle Topologie, Aromatizität und die photophysischen Eigenschaften wurden per NMR Spektroskopie, Einkristallstrukturanalyse, UV/Vis Absorptionsspektroskopie sowie durch DFT Simulationen untersucht. Diese Strategie stellt eine neue Herangehensweise für die zügige Synthese bisher nicht erforschter, nicht‐alternierender PAKs oder Graphennanostreifen mit mehreren Azuleneinheiten dar. [ABSTRACT FROM AUTHOR]

Instead of concluding with a pessimism, however, Garrido points out that the reification of the subject for the perfection of the constitutive principle is not peculiar to capitalism; it exists likewise in the religious and in the artistic form of life, for instance. Ontological conversion, Garrido concludes, is "the constant source of the authenticity, universality and intersubjectivity of the subject" (Garrido, 2021, p. 99). Garrido cites James Heartfield's words that "the human subject persists, but in denial of its own subjectivity" (Heartfield, 2006, p. 238; Garrido, 2021, p. 230). [Extracted from the article]

This article formulates the "enigma of time" as the paradoxical compatibility between the apparent completeness of a temporal object's presence and the actual incompleteness of its manifestation. Proceeding with the methodological assumption that this paradox cannot be "solved" by positing an atemporal foundation (while compartmentalizing temporality to the extent that it becomes ontologically superfluous), I point to a constant risk in Husserl's transcendental phenomenology that the temporality of temporal phenomena is traced to an atemporal activity arranging equally atemporal contents—and thereby is explained away rather than explained. The risk was already recognizable in the "schematic model" of apprehension, and it persisted in the foundationalist interpretation of "absolute time-consciousness." By contrast, I suggest a hermeneutics that takes time seriously, which comprehends the paradox and make it the productive core of philosophizing. Only in this way can time cease to be a petrifying impasse and instead redefine the landscape of philosophy. [ABSTRACT FROM AUTHOR]

• The full-length of NtMYB4a cDNA is 816 bp with an ORF encoding 271 amino acids. • NtMYB4a shows differential spatio-temporal expression. • NtMYB4a positively regulates anthocyanin biosynthesis in tobacco corolla. • NtMYB4a is involved in abiotic stress responses. The MYB transcription factors are involved in the regulation of plant secondary metabolism, cell development and morphogenesis, and stress response. Here, a full-length, 816-bp NtMYB4a cDNA, which encodes a protein comprising 271 amino acids, was isolated from tobacco leaves. Phylogenetic analysis revealed that NtMYB4a is most similar to Nicotiana. attenuata MYB4, followed by Eriobotrya japonica MYB4 , and NtMYB4a clustered with transcriptional activators rather than repressors. Subcellular localization assays showed that NtMYB4 localized in the nucleus, membrane, and cytoplasm. Expression analyses revealed differential expression of NtMYB4a among different tissues and organs and between different developmental stages, with most expression occurring in the stems and leaves during the full-bloom stage. Moreover, NtMYB4a expression was induced by cold, NaCl, PEG, abscisic acid, methyl jasmonate, and dark stressors, and the expression patterns and maximum expression levels varied with the type of stress. Overexpression of NtMYB4a upregulated NtPAL , Nt4CL , NtCHS , NtCHI , NtF3H , NtDFR , NtANS , and NtUFGT , which resulted in increased anthocyanin content in the tobacco corolla and darker colors. However, CRISPR/Cas9-mediated knockout of NtMYB4a downregulated NtPAL , NtC4H , Nt4CL , NtCHS , NtCHI , NtF3H , NtANS , and NtUFGT , which resulted in reduced anthocyanin content, and lighter corolla colors. These results indicated that NtMYB4a positively regulates anthocyanin biosynthesis and is involved in abiotic stress responses in tobacco plants. [ABSTRACT FROM AUTHOR]

Calibration transfer is a mathematical or statistical technique to solve the universality of near-infrared (NIR) spectroscopy, which is particularly important in practical applications. Therefore, a calibration transfer method based on local preserving projection (CTLPP) to correct spectral differences was proposed in this paper. Local preserving projection (LPP) is a linear feature extraction algorithm, which is a linear approximation of Laplacian Eigenmap manifold learning. It can not only overcome the shortcomings of linear feature extraction algorithms which are difficult to maintain the nonlinear manifold of the original data, but also solve the problem that nonlinear manifold learning methods are difficult to directly map new samples, which is conducive to building the conversion relationship between the source spectra and the target spectra. The transfer performance of the proposed method was evaluated in three datasets, and compared with five approaches, namely, piecewise direct standardization (PDS), calibration transfer based on independent component analysis (CTICA), spectral space transformation (SST), principal components canonical correlation analysis (PC-CCA) and calibration transfer based on neighborhood preserving embedding (CTNPE). Experimental results indicated that this proposed method can successfully correct the detection spectra among different apparatus. In addition, it can obtain relatively low prediction root mean square error (RMSEP). Therefore, the comprehensive research conducted in this work demonstrated that the proposed method is a promising calibration transfer method in NIR applications, which can provide a reference when sharing the NIR spectral models with more and more instruments. [ABSTRACT FROM AUTHOR]

Background: Glutathione S-transferases (GSTs) are large and multifunctional proteases that play an important role in detoxification, protection against biotic and abiotic stresses, and secondary metabolite transportation which is essential for plant growth and development. However, there is limited research on the identification and function of NtGSTs. Results: This study uses K326 and other six tobacco varieties (Hongda, HG, GDH11, Va116, VG, and GDH88) as materials to conduct comprehensive genome-wide identification and functional characterization of the GST gene in tobacco. A total of 59 NtGSTs were identified and classified into seven subfamilies via the whole-genome sequence analysis, with the Tau type serving as the major subfamily. The NtGSTs in the same branch of the evolutionary tree had similar exon/intron structure and motif constitution. There were more than 42 collinear blocks between tobacco and pepper, tomato, and potato, indicating high homology conservation between them. Twelve segmental duplicated gene pairs and one tandem duplication may have had a substantial impact on the evolution and expansion of the tobacco GST gene family. The RT-qPCR results showed that the expression patterns of NtGSTs varied significantly among tissues, varieties, and multiple abiotic stresses, suggesting that NtGST genes may widely respond to various abiotic stresses and hormones in tobacco, including NtGSTF4, NtGSTL1, NtGSTZ1, and NtGSTU40. Conclusions: This study provides a comprehensive analysis of the NtGST gene family, including structures and functions. Many NtGSTs play a critical regulatory role in tobacco growth and development, and responses to abiotic stresses. These findings offer novel and valuable insights for understanding the biological function of NtGSTs and the reference materials for cultivating highly resistant varieties and enhancing the yield and quality of crops. [ABSTRACT FROM AUTHOR]

Background: Potassium(K+) plays a vital role in improving the quality of tobacco leaves. However, how to improve the potassium content of tobacco leaves has always been a difficult problem in tobacco planting. K+ content in tobacco hybrid is characterized by heterosis, which can improve the quality of tobacco leaves, but its underlying molecular genetic mechanisms remain unclear. Results: Through a two-year field experiment, G70×GDH11 with strong heterosis and K326×GDH11 with weak heterosis were screened out. Transcriptome analyses revealed that 80.89% and 57.28% of the differentially expressed genes (DEGs) in the strong and weak heterosis combinations exhibited an overdominant expression pattern, respectively. The genes that up-regulated the overdominant expression in the strong heterosis hybrids were significantly enriched in the ion homeostasis. Genes involved in K+ transport (KAT1/2, GORK, AKT2, and KEA3), activity regulation complex (CBL-CIPK5/6), and vacuole (TPKs) genes were overdominant expressed in strong heterosis hybrids, which contributed to K+ homeostasis and heterosis in tobacco leaves. Conclusions: K+ homeostasis and accumulation in tobacco hybrids were collectively improved. The overdominant expression of K+ transport and homeostasis-related genes conducted a crucial role in the heterosis of K+ content in tobacco leaves. [ABSTRACT FROM AUTHOR]

Background: The filamentous temperature-sensitive H protease (ftsH) gene family plays an important role in plant growth and development. FtsH proteins belong to the AAA protease family. Studies have shown that it is a key gene for plant chloroplast development and photosynthesis regulation. In addition, the ftsH gene is also involved in plant response to stress. At present, the research and analysis of the ftsH gene family are conducted in microorganisms such as Escherichia coli and Oenococcus and various plants such as Arabidopsis, pear, rice, and corn. However, analysis reports on ftsH genes from tobacco (Nicotiana tabacum L.), an important model plant, are still lacking. Since ftsH genes regulate plant growth and development, it has become necessary to systematically study this gene in an economically important plant like tobacco. Results: This is the first study to analyze the ftsH gene from Nicotiana tabacum L. K326 (NtftsH). We identified 20 ftsH genes from the whole genome sequence, renamed them according to their chromosomal locations, and divided them into eight subfamilies. These 20 NtftsH genes were unevenly distributed across the 24 chromosomes. We found four pairs of fragment duplications. We further investigated the collinearity between these genes and related genes in five other species. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis identified differential expression patterns of NtftsH in different tissues and under various abiotic stress conditions. Conclusions: This study provides a comprehensive analysis of the NtftsH gene family. The exon–intron structure and motif composition are highly similar in NtftsH genes that belong to the same evolutionary tree branch. Homology analysis and phylogenetic comparison of ftsH genes from several different plants provide valuable clues for studying the evolutionary characteristics of NtftsH genes. The NtftsH genes play important roles in plant growth and development, revealed by their expression levels in different tissues as well as under different stress conditions. Gene expression and phylogenetic analyses will provide the basis for the functional analysis of NtftsH genes. These results provide a valuable resource for a better understanding of the biological role of the ftsH genes in the tobacco plant. [ABSTRACT FROM AUTHOR]

Background: Potassium(K+) plays a vital role in improving the quality of tobacco leaves. However, how to improve the potassium content of tobacco leaves has always been a difficult problem in tobacco planting. K+ content in tobacco hybrid is characterized by heterosis, which can improve the quality of tobacco leaves, but its underlying molecular genetic mechanisms remain unclear. Results: Through a two-year field experiment, G70×GDH11 with strong heterosis and K326×GDH11 with weak heterosis were screened out. Transcriptome analyses revealed that 80.89% and 57.28% of the differentially expressed genes (DEGs) in the strong and weak heterosis combinations exhibited an overdominant expression pattern, respectively. The genes that up-regulated the overdominant expression in the strong heterosis hybrids were significantly enriched in the ion homeostasis. Genes involved in K+ transport (KAT1/2, GORK, AKT2, and KEA3), activity regulation complex (CBL-CIPK5/6), and vacuole (TPKs) genes were overdominant expressed in strong heterosis hybrids, which contributed to K+ homeostasis and heterosis in tobacco leaves. Conclusions: K+ homeostasis and accumulation in tobacco hybrids were collectively improved. The overdominant expression of K+ transport and homeostasis-related genes conducted a crucial role in the heterosis of K+ content in tobacco leaves. [ABSTRACT FROM AUTHOR]

Open‐shell non‐alternant polycyclic hydrocarbons (PHs) are attracting increasing attention due to their promising applications in organic spintronics and quantum computing. Herein we report the synthesis of three cyclohepta[def]fluorene‐based diradicaloids (1–3), by fusion of benzo rings on its periphery for the thermodynamic stabilization, as evidenced by multiple characterization techniques. Remarkably, all of them display a very narrow optical energy gap (Egopt=0.52–0.69 eV) and persistent stability under ambient conditions (t1/2=11.7–33.3 h). More importantly, this new type of diradicaloids possess a low‐lying triplet state with an extremely small singlet–triplet energy gap, as low as 0.002 kcal mol−1, with a clear dependence on the molecular size. This family of compounds thus offers a new route to create non‐alternant open‐shell PHs with high‐spin ground states, and opens up novel possibilities and insights into understanding the structure–property relationships. [ABSTRACT FROM AUTHOR]

Open‐shell non‐alternant polycyclic hydrocarbons (PHs) are attracting increasing attention due to their promising applications in organic spintronics and quantum computing. Herein we report the synthesis of three cyclohepta[def]fluorene‐based diradicaloids (1–3), by fusion of benzo rings on its periphery for the thermodynamic stabilization, as evidenced by multiple characterization techniques. Remarkably, all of them display a very narrow optical energy gap (Egopt=0.52–0.69 eV) and persistent stability under ambient conditions (t1/2=11.7–33.3 h). More importantly, this new type of diradicaloids possess a low‐lying triplet state with an extremely small singlet–triplet energy gap, as low as 0.002 kcal mol−1, with a clear dependence on the molecular size. This family of compounds thus offers a new route to create non‐alternant open‐shell PHs with high‐spin ground states, and opens up novel possibilities and insights into understanding the structure–property relationships. [ABSTRACT FROM AUTHOR]

Background: The basic leucine zipper (bZIP) transcription factor (TF) is one of the largest families of transcription factors (TFs). It is widely distributed and highly conserved in animals, plants, and microorganisms. Previous studies have shown that the bZIP TF family is involved in plant growth, development, and stress responses. The bZIP family has been studied in many plants; however, there is little research on the bZIP gene family in tobacco. Results: In this study, 77 bZIPs were identified in tobacco and named NtbZIP01 through to NtbZIP77. These 77 genes were then divided into eleven subfamilies according to their homology with Arabidopsis thaliana. NtbZIPs were unevenly distributed across twenty-two tobacco chromosomes, and we found sixteen pairs of segmental duplication. We further studied the collinearity between these genes and related genes of six other species. Quantitative real-time polymerase chain reaction analysis identified that expression patterns of bZIPs differed, including in different organs and under various abiotic stresses. NtbZIP49 might be important in the development of flowers and fruits; NtbZIP18 might be an important regulator in abiotic stress. Conclusions: In this study, the structures and functions of the bZIP family in tobacco were systematically explored. Many bZIPs may play vital roles in the regulation of organ development, growth, and responses to abiotic stresses. This research has great significance for the functional characterisation of the tobacco bZIP family and our understanding of the bZIP family in higher plants. [ABSTRACT FROM AUTHOR]

Heterosis is a common biological phenomenon that can be used to optimize yield and quality of crops. Using heterosis breeding, hybrids with suitable nicotine content have been applied to tobacco leaf production. However, the molecular mechanism of the formation of nicotine heterosis has never been explained from the perspective of protein. The DIA proteomics technique was used to compare the differential proteomics of the hybrid Va116 × Basma, showing strong heterosis in nicotine content from its parent lines Va116 and Basma. Proteomics analysis indicated that 65.2% of DEPs showed over-dominant expression patterns, and these DEPs included QS, BBL, GS, ARAF and RFC1 which related to nicotine synthesis. In addition, some DEPs (including GST, ABCE2 and ABCF1 and SLY1) that may be associated with nicotinic transport exhibited significant heterosis over the parental lines. These findings demonstrated that the efficiency of the synthesis and transport of nicotine in hybrids was significantly higher than that in the parent lines, and the accumulation of over-dominant expression proteins may be the cause of heterosis of nicotinic content in hybrids. [ABSTRACT FROM AUTHOR]

Cold stress is a non-biological stressor that adversely affects tobacco yield and leaf quality. Plant photoreceptor proteins, which function as dual light-temperature sensors, play a vital role in temperature changes, making them crucial for responses to non-biological stressors. However, the regulatory mechanisms of PhyA in tobacco remain poorly understood. Therefore, in this study, we aimed to clone the NtPhyA gene from tobacco and generate overexpression (OE- NtPhyA) and mutant (KO- NtPhyA) constructs of NtPhyA. By assessing the physiological and biochemical responses of the mutants under cold stress and performing transcriptome sequencing, we determined the signalling mechanism of NtPhyA under cold stress. Comparative analysis with wild-type (WT) NtPhyA revealed that KO- NtPhyA exhibited increased seed germination rates and reduced wilting under cold stress. In additional, the degree of damage to leaf cells, cell membranes, and stomatal structures was mitigated, and the levels of reactive oxygen species (ROS) were significantly decreased. Antioxidant enzyme activity, net photosynthetic rate, and Fv/Fm were significantly enhanced in KO- NtPhyA , whereas the opposite effects were observed in OE- NtPhyA. These findings indicate that KO- NtPhyA augments tobacco tolerance to cold stress, implying a negative regulatory role of NtPhyA in tobacco during cold stress. Transcriptome analysis revealed that NtPhyA governs the expression of a cascade of genes involved in the response to oxygen-containing compounds, hydrogen peroxide (H 2 O 2) , ROS, temperature stimuli, photosystem II oxygen-evolving complex assembly, water channel activity, calcium channel activity, and carbohydrate transport. Collectively, our findings indicate that NtPhyA activates downstream gene expression to enhance the resilience of tobacco to cold stress. • NtPhyA mutants resulted in increased cold tolerance in tobacco. • NtPhyA mutants increases seed germination rate under cold stress. • NtPhyA mutants reduces damage to cell membranes and stomatal structures under cold stress. • NtPhyA mutants significantly reduced the levels of ROS under cold stress. • NtPhyA mutants significantly enhanced antioxidant enzyme activity under cold stress. [ABSTRACT FROM AUTHOR]

Cytoplasmic male sterility (CMS) is critical in maximizing crop yield and quality by utilizing tobacco heterosis. However, the mechanism of tobacco CMS formation remains unknown. Using paraffin section observation, transcriptome sequencing, and TMT proteomic analysis, this study describes the differences in expression profiles in morphology, transcription, and translation between the sua-CMS tobacco line (MSYY87) and its corresponding maintainer line (YY87). According to the microspore morphology, MSYY87 began to exhibit abnormal microspore development during the early stages of germination and differentiation (androgynous primordium differentiation stage). According to transcriptomic and proteomic analyses, 17 genes/proteins involved in lipid transport/binding and phenylpropane metabolism were significantly down-regulated at both the mRNA and protein levels. Through further analysis, we identified some key genes that may be involved in tobacco male sterility, including β-GLU related to energy metabolism, 4CL and bHLHs related to anther wall formation, nsLTPs related to pollen germination and anther cuticle, and bHLHs related to pollen tapetum degradation. We speculate that the down-regulation of these genes affects the normal physiological metabolism, making tobacco plants show male sterility. Cytoplasmic male sterility (CMS) plays a vital role in utilizing tobacco heterosis and enhancing crop yield and quality. We observed paraffin sections and conducted transcriptome sequencing and mitochondrial proteomics to examine the tobacco CMS line Yunyan 87 (MSYY87) and its maintainer line Yunyan 87 (YY87). The down-regulation expression of β-GLU resulted in insufficient ATP supply, which resulted in disordered energy metabolism. The down-regulation expression of 4CL , nsLTPs and bHLHs may affect the formation of anther wall and anther cuticle, pollen germination, as well as the degradation of pollen tapetum. These various abnormal physiological processes, the male sterility of tobacco is finally caused. The findings shed light on the molecular mechanisms of tobacco CMS and serve as a model for fertility research in other flowering plants. [Display omitted] • CMS line MSYY87 with the cytoplasm of wild tobacco had no negative effects on the appearance of tobacco plants. • MSYY87 began to exhibit abnormal microspore development during the early stages of germination and differentiation. • Integrated transcriptome and proteome analysis revealed the different expressed genes/proteins were related to pollen germination, development and maturation, pollen exine formation, pollen sperm cell differentiation, anther development etc. • The down-regulated expression of BGLU, ns-LTPs, ALT, 4CL and bHLHs in MSYY87 caused a variety of abnormal physiological phenomena, and finally contribute to the emergence of male sterility in tobacco. [ABSTRACT FROM AUTHOR]

The extensive use of metolachlor to control weeds in tobacco fields in China has aroused concern about its environmental fate. The aim of this study was to investigate the degradation and residue fate of metolachlor in tobacco field soil (silt loam) under laboratory and field conditions. In laboratory experiments, metolachlor in bulk soil exhibited fast degradation in a temperature range from 10 to 35°C and a soil moisture level of 20–80%, with half-lives (T1/2) from 66.7 to 28.8 days. The degradation rate of metolachlor decreased as the application dose increased. Owing to higher microbial populations and enzymatic activities, metolachlor rapidly dissipated in rhizosphere soil as compared to bulk soil. Field persistence of metolachlor was evaluated in the same soil during the tobacco (Nicotiana tabacumK326) growing season in 2012 and 2013. The dissipation of metolachlor followed the first-order kinetics and itsT1/2values were 11.7–13.5 days in soil and 9.0–9.6 days in green tobacco leaves, respectively. At harvest time, the residual levels of metolachlor in soil and green tobacco leaves were in the range of 0.626–1.623 and 0.083-0.481 mg kg−1, respectively. These findings might have practical implications for the fate of metolachlor residue in tobacco fields. Environmental factors, especially temperature and moisture, should be considered in combination with the appropriate application dose of metolachlor for achieving satisfactory weed-control efficacy, reducing runoff, and minimizing effects on environmental quality. [ABSTRACT FROM AUTHOR]

Background: As a unique biological phenomenon, heterosis has been concerned with the superior performance of the heterosis than either parents. Despite several F1 hybrids, containing supernal nicotine content, had been discovered and applied to heterosis utilization in Nicotiana tabacum L., nevertheless, the potential molecular mechanism revealing nicotine heterosis has not been illustrated clearly. Result: Phenotypically, the F1 hybrids (Vall6 × Basma) show prominent heterosis in nicotine content by 3 years of field experiments. Transcriptome analysis revealed that genes participating in nicotine anabolism (ADC, PMT, MPO, QPT, AO, QS, QPT, A622, BBLs) and nicotine transport (JAT2, MATE1 and 2, NUP1 and 2) showed an upregulated expression in the hybrid, a majority of which demonstrated an overdominant performance. RT-PCR confirmed that nicotine anabolism was induced in the hybrid. Conclusions: These findings strongly suggest that nicotine synthesis and transport efficiency improved in hybrid and overdominance at gene-expression level played a critical role in heterosis of nicotine metabolism. [ABSTRACT FROM AUTHOR]