Metal Clusters Confined in Chiral Zeolitic Imidazolate Framework for Circularly Polarized-Luminescence Inks.

Chiroptical activities arising in nanoclusters (NCs) are emerging as one of the most dynamic areas of modern science. However, devising an overarching strategy that is capable of concurrently enhancing the photoluminescence (PL) and circularly polarized luminescence (CPL) of metal NCs remains a formidable challenge. Herein, gold and silver nanoclusters (AuNCs, AgNCs) are endowed with CPL, for the first time, through a universal host-guest approach─centered around perturbing a chiral microenvironment within chiral hosts, simultaneously enhancing emissions. Remarkably, the photoluminescence quantum yield (PLQY) of AuNCs has undergone an increase of over 200 times upon confinement, escalating from 0.05% to 12%, and demonstrates a CPL response. Moreover, a three-dimensional (3D) model termed "NCs@CMOF" featuring CPL activity is created using metal cluster-based assembly inks through the process of 3D printing. This work introduces a potentially straightforward and versatile approach for achieving both PL enhancement and CPL activities in metal clusters.

Discovery of novel tetrahydrobenzothiophene derivatives as MSBA inhibitors for antimicrobial agents.

The incidence of infections caused by drug-resistant bacteria has been one of the most serious health threats in the past and is substantially increasing in an alarming rate. Therefore, the development of new antimicrobial agents to combat bacterial resistance effectively is urgent. This study focused on the design and synthesis of 40 novel tetrahydrobenzothiophene amide/sulfonamide derivatives and their antibacterial activities were evaluated. Compounds 2p, 6p, and 6 s exhibited significant inhibitory effects on the growth of bacteria. To assess their safety, the cytotoxicity of the compounds was assessed using human normal liver cells, revealing that compound 6p has lower cytotoxicity. A mouse wound healing experiment demonstrated that compound 6p effectively improved wound infection induced by trauma and accelerated the healing process. Compound 6p holds promise as a potential therapeutic agent for combating bacterial infections.

Can single progesterone concentration predict miscarriage in early pregnant women with threatened miscarriage: a systematic review and meta-analysis.

BACKGROUND: About 25% of pregnant women experience bleeding in the early stage, and half of them eventually progress to pregnancy loss. Progesterone serves as a useful biomarker to predict miscarriage in threatened miscarriage, yet its performance is still debated. AIM: To evaluate the performance of single serum progesterone predicting miscarriage in early pregnant patients with threatened miscarriage. METHOD: The online database was searched to yield the literature using the terms of 'Abortion', 'Miscarriage', and 'serum Progesterone', including PubMed, Scopus, Embase, Cochrane library, and China national knowledge infrastructure. Receiver operating characteristic (ROC) curve, likelihood ratio (LLR) and diagnostic odds ratio (DOR) and 95% confidence interval (CI) were computed. Publication bias was assessed by the deeks funnel plot asymmetry test. Subgroup analyses were conducted according to the progesterone level (< 12 ng/mL), recruited location and region, progesterone measurement method, exogenous progesterone supplement and follow up. RESULTS: In total, 12 studies were eligible to be included in this study, with sample sizes ranging from 76 to 1087. The included patients' gestational age was between 4 and 12 weeks. No significant publication bias was detected from all included studies. The threshold of progesterone reported ranged from 8 to 30 ng/ml. The synthesized area under the ROC curve (0.85, 95% CI 0.81 to 0.88), positive LLR (6.2, 4.0 to 9.7) and DOR (18, 12 to 27) of single progesterone measurement distinguishing miscarriage were relatively good in early pregnant patients with threatened miscarriage. When the threshold of < 12 ng/mL was adapted, the progesterone provided a higher area under the ROC curve (0.90 vs. 0.78), positive LLR (8.3 vs. 3.8) and DOR (22 vs.12) than its counterpart (12 to 30 ng/mL). CONCLUSION: Single progesterone measurement can act as a biomarker of miscarriage in early pregnant patients with threatened miscarriage, and it has a better performance when the concentration is <12 ng/mL. TRIAL REGISTRATION: PROSPERO (CRD42021255382).

The current perspective and opportunities of small nucleic acid-based therapeutics.

Compared to traditional small molecule and antibody drugs, RNA-based drugs offer a simple design, short research and development cycles, high specificity, broad treatment fields, and long-term efficacy. As a result, RNA-based drugs are extensively used to treat genetic diseases, tumors, viral infections, and other illnesses, suggesting that they have the potential to become the third-largest drug class after small molecule and antibody drugs. Currently, more than 10 small nucleic acid drugs have gained regulatory approval. The commercialization successes of small nucleic acid drugs will stimulate the development of RNA-based drugs. Small nucleic acid drugs primarily target liver diseases, metabolic diseases, genetic diseases, and tumors, and there is also significant potential for expanding indications in the future. This review provides a brief overview of the advantages and development of small nucleic acid-based therapeutics and shows a focus on platform technologies such as chemical modifications and delivery systems that have enabled the clinical translation of small nucleic acid-based therapeutics. Additionally, we summarize the latest clinical progress in small nucleic acid-based therapeutics for the treatment of various diseases, including rare diseases, liver diseases, metabolic diseases, and tumors. Finally, we highlight the future prospects for this promising treatment approach.

Neoadjuvant docetaxel and capecitabine (TX) versus docetaxel and epirubicin (TE) for locally advanced or early her2-negative breast cancer: an open-label, randomized, multi-center, phase II Trial.

PURPOSE: The combination of taxanes and anthracyclines is still the mainstay of chemotherapy for early breast cancer. Capecitabine is an active drug with a favorable toxicity profile, showing strong anti-tumor activity against metastatic breast cancer. This trial assessed the efficacy and safety of the TX regimen (docetaxel and capecitabine) and compared it with the TE (docetaxel and epirubicin) regimen in locally advanced or high risk early HER2-negative breast cancer. PATIENTS AND METHODS: This randomized clinical trial was conducted at five academic centers in China. Eligible female patients were randomly assigned (1:1) to the TX (docetaxel 75 mg/m2 d1 plus capecitabine 1000 mg/m2 twice d1-14, q3w) or TE (docetaxel 75 mg/m2 d1 plus epirubicin 75 mg/m2 d1, q3w) groups for four cycles. The primary endpoint was a pathological complete response in the breast (pCR). Secondary endpoints included pCR in the breast and axilla, invasive disease-free survival (iDFS), overall survival (OS), and safety. RESULTS: Between September 1, 2012, and December 31, 2018, 113 HER2-negative patients were randomly assigned to the study groups (TX: n = 54; TE: n = 59). In the primary endpoint analysis, 14 patients in the TX group achieved a pCR, and nine patients in the TE group achieved a pCR (25.9% vs. 15.3%), with a not significant difference of 10.6% (95% CI -6.0-27.3%; P = 0.241). In a subgroup with high Ki-67 score, TX increased the pCR rate by 24.2% (95% CI 2.2-46.1%; P = 0.029). At the end of the 69-month median follow-up period, both groups had equivalent iDFS and OS rates. TX was associated with a higher incidence of hand-foot syndrome and less alopecia, with a manageable toxicity profile. CONCLUSION: The anthracycline-free TX regimen yielded comparable pCR and long-term survival rates to the TE regimen. Thus, this anthracycline-free regimen could be considered in selected patients. TRIAL REGISTRATION: ACTRN12613000206729 on 21/02/2013, retrospectively registered.

Pyranodipyran Derivatives with Tyrosyl DNA Phosphodiesterase 1 Inhibitory Activities and Fluorescent Properties from Aspergillus sp. EGF 15-0-3.

Four new benzodipyran racemates, namely (±)-aspergiletals A-D (3-6), representing a rare pyrano[4,3-h]chromene scaffold were isolated together with eurotiumide G (1) and eurotiumide F (2) from the soft-coral-derived fungus Aspergillus sp. EGF 15-0-3. All the corresponding optically pure enantiomers were successfully separated by a chiral HPLC column. The structures and configurations of all the compounds were elucidated based on the combination of NMR and HRESIMS data, chiral separation, single-crystal X-ray diffraction, quantum chemical 13C NMR, and electronic circular dichroism calculations. Meanwhile, the structure of eurotiumide G was also revised. The TDP1 inhibitor activities and photophysical properties of the obtained compounds were evaluated. In the TDP1 inhibition assay, as a result of synergy between (+)-6 and (-)-6, (±)-6 displayed strong inhibitory activity to TDP1 with IC50 values of 6.50 ± 0.73 µM. All compounds had a large Stokes shift and could be utilized for elucidating the mode of bioactivities by fluorescence imaging.

Evaluation of a nurse-supervised rehabilitation programme on clinical features and systemic inflammation in Chinese children with asthma: A propensity score-matched analysis.

AIMS: To evaluate whether a nurse-supervised rehabilitation programmes could improve respiratory functions and systematic inflammation in children with asthma. BACKGROUND: Children with asthma always suffer from poor life quality, and physical training and pulmonary rehabilitation could be beneficial to asthma. DESIGN: A retrospective, observational, single-centre cohort analysis. METHOD: Baseline characteristics between the nurse-supervised rehabilitation programme and usual-care groups were matched by propensity-score matching (PSM) in a 1:1 ratio. We compared the lung function and inflammatory markers between groups. RESULTS: Among 52 pairs of children, differences in lung function were improved in the nurse-supervised rehabilitation group compared with those in usual-care group, including the oxygen saturation, forced expiratory volume in 1 second, forced expiratory flow of 25%-75% and peak expiratory flow (all P < 0.05). Two asthma-related inflammatory markers (hypersensitive C-reactive protein and immunoglobulin E) also significantly decreased in the nurse-supervised rehabilitation group (both P < 0.001). CONCLUSIONS: The results indicate that the nurse-supervised rehabilitation programme might be effective in improving symptom control, respiratory functions and systemic inflammation in children with asthma. The study suggests that the NSR for asthma merits further research.

Valley-Layer Coupling: A New Design Principle for Valleytronics.

The current valleytronics research is based on the paradigm of time-reversal-connected valleys in two-dimensional (2D) hexagonal materials, which forbids the fully electric generation of valley polarization by a gate field. Here, we go beyond the existing paradigm to explore 2D systems with a novel valley-layer coupling (VLC) mechanism, where the electronic states in the emergent valleys have a valley-contrasted layer polarization. The VLC enables a direct coupling between a valley and a gate electric field. We analyze the symmetry requirements for a system to host VLC, demonstrate our idea via first-principles calculations and model analysis of a concrete 2D material example, and show that an electric, continuous, wide-range, and switchable control of valley polarization can be achieved by VLC. Furthermore, we find that systems with VLC can exhibit other interesting physics, such as valley-contrasting linear dichroism and optical selection of the valley and the electric polarization of interlayer excitons. Our finding opens a new direction for valleytronics and 2D materials research.

Computational prediction of a novel 1D InSeI nanochain with high stability and promising wide-bandgap properties.

Low-dimensional materials have aroused widespread interest for their novel and fascinating properties. Based on first-principles calculations, we predict the one-dimensional (1D) InSeI nanochains with van der Waals (vdW) interchain interactions, which could be exfoliated mechanically and kept at steady states at room temperature. Compared with bulk InSeI, the single nanochain InSeI has a larger direct bandgap of 3.15 eV. Its calculated carrier mobility is as high as 54.17 and 27.49 cm2 V-1 s-1 for holes and electrons, respectively, comparable with those of other 1D materials. In addition, a direct-to-indirect bandgap transition is implemented under a small applied strain (∼6%). More importantly, the nanochains are found to be promising candidates for optoelectronic devices since they possess a high absorption coefficient of ∼105 cm-1 in the ultraviolet region. The results thus pave a novel avenue for the applications of InSeI nanochains with excellent thermal stability in nanoelectronic and optoelectronic devices.

An efficient TILLING platform for cultivated tobacco.

Targeting-induced local lesions in genomes (TILLING) is a powerful reverse-genetics tool that enables high-throughput screening of genomic variations in plants. Although TILLING has been developed for many diploid plants, the technology has been used in very few polyploid species due to their genomic complexity. Here, we established an efficient capillary electrophoresis-based TILLING platform for allotetraploid cultivated tobacco (Nicotiana tabacum L.) using an ethyl methanesulfonate (EMS)-mutagenized population of 1,536 individuals. We optimized the procedures for endonuclease preparation, leaf tissue sampling, DNA extraction, normalization, pooling, PCR amplification, heteroduplex formation, and capillary electrophoresis. In a test screen using seven target genes with eight PCR fragments, we obtained 118 mutants. The mutation density was estimated to be approximately one mutation per 106 kb on average. Phenotypic analyses showed that mutations in two heavy metal transporter genes, HMA2S and HMA4T, led to reduced accumulation of cadmium and zinc, which was confirmed independently using CRISPR/Cas9 to generate knockout mutants. Our results demonstrate that this powerful TILLING platform (available at http://www.croptilling.org) can be used in tobacco to facilitate functional genomics applications.

Molecular characterization of a new recombinant brassica yellows virus infecting tobacco in China.

Brassica yellows virus (BrYV), prevalently distributed throughout mainland China and South Korea while triggering serious diseases in cruciferous crops, is proposed to be a new species in the genus Polerovirus within the family Luteoviridae. There are three distinct genotypes (BrYV-A, BrYV-B and BrYV-C) reported in cabbage and radish. Here, we describe a new BrYV isolate infecting tobacco plants in the field, which was named BrYV-NtabQJ. The complete genome sequence of BrYV-NtabQJ is 5741 nt in length, and 89% of the sequence shares higher sequence identities (about 90%) with different BrYV isolates. However, it possesses a quite divergent region within ORF5, which is more close to Beet western yellows virus (BWYV), Beet mild yellowing virus (BMYV) and Beet chlorosis virus (BChV). A significant recombination event was then detected among BrYV-NtabQJ, BrYV-B Beijng isolate (BrYV-BBJ) and BWYV Leonurus sibiricus isolate (BWYV-LS). It is proposed that BrYV-NtabQJ might be an interspecific recombinant between BrYV-BBJ and BWYV-LS, and the recombination might result in the successful aphid transmission of BrYV from cruciferous crops to tobacco. And it also poses new challenges for BrYV diagnosis and the vegetable production.

Effects of Se substitution and transition metal doping on the electronic and magnetic properties of a MoSxSe2-x/h-BN heterostructure.

The van der Waals heterostructures created by stacking two monolayer semiconductors have been rapidly developed experimentally and exhibit various unique physical properties. In this work, we investigate the effects of Se atom substitution and 3d-TM atom doping on the structural, electronic, and magnetic properties of the MoSe2/h-BN heterostructure, by using first-principles calculations based on density functional theory (DFT). It is found that Se atom substitution could considerably enhance the band gaps of MoSe2/h-BN heterostructures. With an increase in the substitution concentration, the energy band changes from an indirect to a direct band gap when the substitution concentration exceeds a critical value. For 3d-TM atom doping, it is shown that V-, Mn-, Fe-, and Co-doped systems exhibit a half-metallic state and magnetic behavior, while there is no spin polarization in the Ni-doped case. The results provide a theoretical basis for the development of diluted magnetic semiconductors and spin devices based on the MoSxSe2-x/h-BN heterostructure.

Establishment and evaluation of a model for predicting 3-month mortality in Chinese patients with hepatic encephalopathy.

Hepatic encephalopathy (HE) is a serious complication of liver disease. To establish a model for predicting 3-month mortality in patients with HE in China. This retrospective study included 609 patients with HE admitted to the Peoples' Hospital, Liaocheng City, China (August 2006 to January 2016). Patients were allocated to a modeling (n = 409) or validation (n = 200) group. Demographic/clinical characteristics, laboratory test results, Model for End Stage Liver Disease (MELD) score and Child-Turcotte-Pugh (CTP) score were extracted from medical records. A model for predicting death within 3 months after admission was established using logistic regression analysis (modeling group). Model validity (validation group) was assessed using receiver operating characteristic (ROC) curve analysis. 270/409(66.0%) patients died in the modeling group and 142/203(70.0%) died in the validation group. Compared with survivors, patients who died had more severe HE, and higher MELD score, CTP score, incidence of complications including hepatorenal syndrome (HRS) and upper gastrointestinal bleeding, and values for laboratory parameters including red blood cell count(RBC) and total bilirubin(TBIL)(P < 0.05). Regression analysis revealed RBC, TBIL, HE stage, HRS and upper gastrointestinal bleeding as independent factors associated with death (P < 0.05). The area under the ROC curve (AUC) for the model was 0.931.The model had a higher Youden index than MELD or CTP scores and predicted death in the validation group with a sensitivity of 83.1% and specificity of 93.4%. The established model has superior performance to MELD and CTP scores for predicting mortality in patients with HE.

Comparison of surgical complication between immediate implant and autologous breast reconstruction after mastectomy: A multicenter study of 426 cases.

BACKGROUND AND OBJECTIVES: There is a lack of multicenter immediate breast reconstruction data comparing the surgical complication of implant and autologous breast reconstruction, especially in China. In this study, we used the data from eight centers to study the complications and their risk factors in this population. METHODS: Sociodemographic and clinicopathological data were obtained and compared for patients who received immediate implant and autologous breast reconstruction after breast cancer surgery in the eight hospitals between 2012 and 2016. Logistic regression analysis was used to identify risk factors associated with the complication of breast reconstruction. RESULTS: Immediate autologous reconstruction (IAR) was associated with significantly higher rates of overall complications (P = 0.036), fat liquefaction (P < 0.001), and reconstructive failure (P = 0.019), but lower rates of wound complications (P = 0.01) compared with the immediate implant reconstruction (IIR) at the median follow-up time of 13.6 months. With the logistic regression analysis, older patient (odds ratio [OR], 2.22; 95% confidence interval [CI], 1.15-4.28; P = 0.017), and obesity (OR, 2.17; 95% CI, 1.08-4.37; P = 0.030) were significant predictors of increased complications. CONCLUSION: Our multicenter results demonstrated that the rates of overall complications and reconstruction failure were higher after IAR than IIR. These findings can be used to better help surgeons and their patients with objective and reliable information to assist in selecting the modality of reconstruction.

Investigation of an "alternate water supply system" in enzymatic hydrolysis in the processive endocellulase Cel7A from Rasamsonia emersonii by molecular dynamics simulation.

Cel7A from Rasamsonia emersonii is one of the processive endocellulases classified under family 7 glycoside hydrolase. Molecular dynamics simulations were carried out to obtain the optimized sliding and hydrolyzing conformations, in which the reducing ends of sugar chains are located on different sites. Hydrogen bonds are investigated to clarify the interactions between protein and substrate in either conformation. Nine hydrogen bonding interactions are identified in the sliding conformation, and six similar interactions are also found correspondingly in the hydrolyzing conformation. In addition, four strong hydrophobic interactions are also determined. The domain cross-correlation map analysis shows movement correlation of protein including autocorrelation between residues. The root mean square fluctuations analysis represents the various flexibilities of different fragment in the two conformations. Comparing the two conformations reveals the water-supply mechanism of selective hydrolysis of cellulose in Cel7A. The mechanism can be described as follow. When the reducing end of substrate slides from the unhydrolyzing site (sliding conformation) to the hydrolyzing site (hydrolyzing conformation), His225 is pushed down and rotated, the rotation leads to the movement of Glu209 with the interstrand hydrogen bonding in ß-sheet. It further makes Asp211 close to the hydrolysis center and provides a water molecule bounding on its carboxyl in the previous unhydrolyzing site. After the hydrolysis takes place and the product is excluded from the enzyme, the Asp211 comes back to its initial position. In summary, Asp211 acts as an elevator to transport outer water molecules into the hydrolysis site for every other glycosidic bond.

Tailoring lanthanide doping in perovskite CaTiO3 for luminescence applications.

Perovskite oxide materials have been attracting significant attention due to their rich physical and chemical properties. With its proven stability and bio-compatibility, we suggest the lanthanide-doped perovskite to be a promising material for biological luminescence applications. Here, taking CaTiO3 as a concrete example, we systematically investigate its doping properties using first-principles computational methods. We determine the conditions allowing the growth of CaTiO3 against various competing phases. We obtain the formation energies of various intrinsic point defects in the material. The doping configuration and the charge state of the lanthanide dopants are determined. We find that for heavier elements in the lanthanide family, the substitution at the Ca site is favored under p-type growth conditions and tends to be trivalent, whereas the substitution at the Ti site is favored under n-type growth conditions and tends to be divalent. And for lighter elements in the family, the substitution at the Ca site is more favored for most cases and the dopant is more likely to be trivalent. By tuning the growth conditions, one could control the valence state of the lanthanide dopant, which in turn controls the luminescence spectra. We collect and identify the emission peaks in the infrared biological window, based on which possible doping schemes are suggested for bio-labeling and imaging applications.

Blue Phosphorene Oxide: Strain-Tunable Quantum Phase Transitions and Novel 2D Emergent Fermions.

Tunable quantum phase transitions and novel emergent fermions in solid-state materials are fascinating subjects of research. Here, we propose a new stable two-dimensional (2D) material, the blue phosphorene oxide (BPO), which exhibits both. On the basis of first-principles calculations, we show that its equilibrium state is a narrow-bandgap semiconductor with three bands at low energy. Remarkably, a moderate strain can drive a semiconductor-to-semimetal quantum phase transition in BPO. At the critical transition point, the three bands cross at a single point at Fermi level, around which the quasiparticles are a novel type of 2D pseudospin-1 fermions. Going beyond the transition, the system becomes a symmetry-protected semimetal, for which the conduction and valence bands touch quadratically at a single Fermi point that is protected by symmetry, and the low-energy quasiparticles become another novel type of 2D double Weyl fermions. We construct effective models characterizing the phase transition and these novel emergent fermions, and we point out several exotic effects, including super Klein tunneling, supercollimation, and universal optical absorbance. Our result reveals BPO as an intriguing platform for the exploration of fundamental properties of quantum phase transitions and novel emergent fermions and also suggests its great potential in nanoscale device applications.

The alteration of protein prenylation induces cardiomyocyte hypertrophy through Rheb-mTORC1 signalling and leads to chronic heart failure.

G protein-regulated cell function is crucial for cardiomyocytes, and any deregulation of its gene expression or protein modification can lead to pathological cardiac hypertrophy. Herein, we report that protein prenylation, a lipidic modification of G proteins that facilitates their association with the cell membrane, might control the process of cardiomyocyte hypertrophy. We found that geranylgeranyl diphosphate synthase (GGPPS), a key enzyme involved in protein prenylation, played a critical role in postnatal heart growth by regulating cardiomyocyte size. Cardiac-specific knockout of GGPPS in mice led to spontaneous cardiac hypertrophy, beginning from week 4, accompanied by the persistent enlargement of cardiomyocytes. This hypertrophic effect occurred by altered prenylation of G proteins. Evaluation of the prenylation, membrane association and hydrophobicity showed that Rheb was hyperactivated and increased mTORC1 signalling pathway after GGPPS deletion. Protein farnesylation or mTORC1 inhibition blocked GGPPS knockdown-induced mTORC1 activation and suppressed the larger neonatal rat ventricle myocyte size and cardiomyocyte hypertrophy in vivo, demonstrating a central role of the FPP-Rheb-mTORC1 axis for GGPPS deficiency-induced cardiomyocyte hypertrophy. The sustained cardiomyocyte hypertrophy progressively provoked cardiac decompensation and dysfunction, ultimately causing heart failure and adult death. Importantly, GGPPS was down-regulated in the hypertrophic hearts of mice subjected to transverse aortic constriction (TAC) and in failing human hearts. Moreover, HPLC-MS/MS detection revealed that the myocardial farnesyl diphosphate (FPP):geranylgeranyl diphosphate (GGPP) ratio was enhanced after pressure overload. Our observations conclude that the alteration of protein prenylation promotes cardiomyocyte hypertrophic growth, which acts as a potential cause for pathogenesis of heart failure and may provide a new molecular target for hypertrophic heart disease clinical therapy.

Genome-wide identification and expression profiling of the C2H2-type zinc finger protein transcription factor family in tobacco.

C2H2 zinc finger protein transcription factor family members have important biological functions in eukaryotes. They not only bind DNA and RNA, but also interact with proteins. In this study, 118 members of the tobacco C2H2 zinc finger protein transcription factor family were identified from the N. tabacum genome database by using Pfam, SMART and Blastp. The analyses of phylogenetic tree, physical and chemical properties, chromosomal mapping, gene structures, protein three-dimensional structures and tissue expression patterns were performed. The results suggested that the peptide length of different subfamily members is significantly different. Phylogenetic and motif analysis revealed that the C2H2 zinc finger protein transcription factor family members can be divided into 5 subfamilies and each member has at least one C2H2 motif. Genes of the family members are distributed across the 22 chromosomes. C2H2 zinc finger protein transcription factor family members are expressed in different tissues although some have higher expression levels in leaves and roots. This study will be helpful for further analysis of the C2H2 zinc finger family proteins in other plants.

Genome-wide identification and expression analysis of the WRKY gene family in common tobacco (Nicotiana tabacum L.).

The coding products of WRKY gene family plays important roles in plant growth and development as well as in various stress responses. They have been identified in various plants, but only few in common tobacco (Nicotiana tabacum L.). In this study, 164 putative WRKY proteins in the common tobacco genome were identified by using the conserved WRKY sequence (PF03106) from the Pfam database. Phylogenetic trees, functional domain analysis, chromosomal localization, subcellular localization and tissue expression patterns were analyzed with the bioinformatics softwares, including DNAMAN 5.0, Weblogo 3, MEGA 5.1, MG2C and MEME. First of all, phylogenetic trees divided all the candidate genes into three subfamilies: Ⅰ, Ⅱ and Ⅲ, respectively, and subfamily Ⅱ could be further divided into five subgroups: group Ⅱ-a, -b, -c, -d and -e. Secondly, the WRKY regions contained a highly conserved heptapeptide stretch WRKYGQK followed by a zinc-finger motif. Most of the NtWRKY genes contained 2-5 exons and a highly conserved gene structure. Thirdly, 154 out of 164 NtWRKY genes were distributed with different densities on 24 chromosomes, and each subfamily with different patterns and frequency. The largest number of NtWRKY genes was found on chromosome VI, and only one on chromosome X. Fourthly, the majority of NtWRKY members located in the nucleus, with 74 percent of subfamily Ⅲ in the extracellular matrix. Lastly, the members in the same subfamily had different spatial and temporal expression profiles, with 11 NtWRKY genes in roots, stems and leaves expressed at various levels. The expression of genes NtWRKY26, NtWRKY30 and NtWRKY32 can be induced by Phytophthora nicotianae. Our research thus provides valuable information for NtWRKY gene cloning and functional characterization in common tobacco.