Conformational Landscapes of 2,3-, 2,4-, 2,5-, and 2,6-Difluorobenzaldehyde Unveiled by Rotational Spectroscopy.

We report the coexistence of anti-conformers and energetically unfavorable syn-conformers of 2,3-, 2,4-, 2,5-, and 2,6-difluorobenzaldehyde in the gas phase using broadband chirped-pulse Fourier transform microwave (CP-FTMW) spectroscopy. The rotational spectra of monosubstituted 13C isotopologues of the anti-conformers have also been assigned in natural abundance, which were used to derive their vibrationally averaged geometries and semi-experimental equilibrium structures. The energy differences between anti- and syn-conformations are estimated to be 10.9, 11.3, and 12.9 kJ/mol for 2,3-, 2,4-, and 2,5-difluorobenzaldehyde, respectively, at the theoretical level of DLPNO-CCSD(T)/def2-TZVP. Despite the steric repulsion caused by the close proximity between the oxygen atom of the aldehyde group and the ortho-substituted fluorine atom, our experimental results indicate the planarity of the syn-conformations. The frequencies of the large amplitude torsion between the phenyl and aldehyde groups have been estimated by experimental inertial defects, which agree with theoretical calculation results.

Analysis of Ginkgo biloba Root Exudates and Inhibition of Soil Fungi by Flavonoids and Terpene Lactones.

Ginkgo biloba is abundant in secondary metabolites, including flavonoids and terpenoids. While the majority of research has focused on the role of these compounds in disease resistance, their specific contribution to pathogen defense has been rarely explored. In this study, we collected root exudates from hydroponically cultivated ginkgo seedlings and conducted a metabolomic analysis. We identified several primary metabolites mainly comprising amino acids and nucleotides, while secondary metabolites consisted of various compounds, including bioactive compounds such as flavonoids and terpenoids. Focusing on the secondary metabolites with relatively higher abundance in the exudates, we selected a mixture of flavonoids and terpenoids for in vitro inhibition experiments against two soil-borne fungal pathogens, Fusarium oxysporum f. sp. cucumerinum that causes cucumber wilt and Rhizoctonia solani AG-8 that causes wheat root rot. The results indicated that the growth rate of both fungus cells was significantly reduced with the increasing concentration of the flavonoid and terpenoid mixture extracted from ginkgo and was completely inhibited at a concentration of 5 mg/mL. Further experiments revealed that this mixture of flavonoids and terpenoids had a destructive effect on the cellular structure of both fungi, thereby reducing cell viability and achieving an antifungal effect. These findings provide a foundation for further research into the use of ginkgo extracts in biological control.

A new transfer entropy method for measuring directed connectivity from complex-valued fMRI data.

Background: Inferring directional connectivity of brain regions from functional magnetic resonance imaging (fMRI) data has been shown to provide additional insights into predicting mental disorders such as schizophrenia. However, existing research has focused on the magnitude data from complex-valued fMRI data without considering the informative phase data, thus ignoring potentially important information. Methods: We propose a new complex-valued transfer entropy (CTE) method to measure causal links among brain regions in complex-valued fMRI data. We use the transfer entropy to model a general non-linear magnitude-magnitude and phase-phase directed connectivity and utilize partial transfer entropy to measure the complementary phase and magnitude effects on magnitude-phase and phase-magnitude causality. We also define the significance of the causality based on a statistical test and the shuffling strategy of the two complex-valued signals. Results: Simulated results verified higher accuracy of CTE than four causal analysis methods, including a simplified complex-valued approach and three real-valued approaches. Using experimental fMRI data from schizophrenia and controls, CTE yields results consistent with previous findings but with more significant group differences. The proposed method detects new directed connectivity related to the right frontal parietal regions and achieves 10.2-20.9% higher SVM classification accuracy when inferring directed connectivity using anatomical automatic labeling (AAL) regions as features. Conclusion: The proposed CTE provides a new general method for fully detecting highly predictive directed connectivity from complex-valued fMRI data, with magnitude-only fMRI data as a specific case.

Estimation of complete mutual information exploiting nonlinear magnitude-phase dependence: Application to spatial FNC for complex-valued fMRI data.

BACKGROUND: Real-valued mutual information (MI) has been used in spatial functional network connectivity (FNC) to measure high-order and nonlinear dependence between spatial maps extracted from magnitude-only functional magnetic resonance imaging (fMRI). However, real-valued MI cannot fully capture the group differences in spatial FNC from complex-valued fMRI data with magnitude and phase dependence. METHODS: We propose a complete complex-valued MI method according to the chain rule of MI. We fully exploit the dependence among magnitudes and phases of two complex-valued signals using second and fourth-order joint entropies, and propose to use a Gaussian copula transformation with a lower bound property to avoid inaccurate estimation of joint probability density function when computing the joint entropies. RESULTS: The proposed method achieves more accurate MI estimates than the two histogram-based (normal and symbolic approaches) and kernel density estimation methods for simulated signals, and enhances group differences in spatial functional network connectivity for experimental complex-valued fMRI data. COMPARISON WITH EXISTING METHODS: Compared with the simplified complex-valued MI and real-valued MI, the proposed method yields higher MI estimation accuracy, leading to 17.4 % and 145.5 % wider MI ranges, and more significant connectivity differences between healthy controls and schizophrenia patients. A unique connection between executive control network (EC) and right frontal parietal areas, and three additional connections mainly related to EC are detected than the simplified complex-valued MI. CONCLUSIONS: With capability in quantifying MI fully and accurately, the proposed complex-valued MI is promising in providing qualified FNC biomarkers for identifying mental disorders such as schizophrenia.

Synergistic Construction of Sub-Nanometer Channel Membranes through MOF-Polymer Composites: Strategies and Nanofiltration Applications.

The selective separation of small molecules at the sub-nanometer scale has broad application prospects in the field, such as energy, catalysis, and separation. Conventional polymeric membrane materials (e.g., nanofiltration membranes) for sub-nanometer scale separations face challenges, such as inhomogeneous channel sizes and unstable pore structures. Combining polymers with metal-organic frameworks (MOFs), which possess uniform and intrinsic pore structures, may overcome this limitation. This combination has resulted in three distinct types of membranes: MOF polycrystalline membranes, mixed-matrix membranes (MMMs), and thin-film nanocomposite (TFN) membranes. However, their effectiveness is hindered by the limited regulation of the surface properties and growth of MOFs and their poor interfacial compatibility. The main issues in preparing MOF polycrystalline membranes are the uncontrollable growth of MOFs and the poor adhesion between MOFs and the substrate. Here, polymers could serve as a simple and precise tool for regulating the growth and surface functionalities of MOFs while enhancing their adhesion to the substrate. For MOF mixed-matrix membranes, the primary challenge is the poor interfacial compatibility between polymers and MOFs. Strategies for the mutual modification of MOFs and polymers to enhance their interfacial compatibility are introduced. For TFN membranes, the challenges include the difficulty in controlling the growth of the polymer selective layer and the performance limitations caused by the "trade-off" effect. MOFs can modulate the formation process of the polymer selective layer and establish transport channels within the polymer matrix to overcome the "trade-off" effect limitations. This review focuses on the mechanisms of synergistic construction of polymer-MOF membranes and their structure-nanofiltration performance relationships, which have not been sufficiently addressed in the past.

Tunable Construction of Chiral Nematic Cellulose Nanocrystals/ZnO Films for Ultra-Sensitive, Recyclable Sensing of Humidity and Ethanol.

The investigation of functional materials derived from sustainable and eco-friendly bioresources has generated significant attention. Herein, nanocomposite films based on chiral nematic cellulose crystals (CNCs) were developed by incorporating xylose and biocompatible ZnO nanoparticles (NPs) via evaporation-induced self-assembly (EISA). The nanocomposite films exhibited iridescent color changes that corresponded to the birefringence phenomenon under polarized light, which was attributed to the formation of cholesteric structures. ZnO nanoparticles were proved to successfully adjust the helical pitches of the chiral arrangements of the CNCs, resulting in tunable optical light with shifted wavelength bands. Furthermore, the nanocomposite films showed fast humidity and ethanol stimuli response properties, exhibiting the potential of stimuli sensors of the CNC-based sustainable materials.

Glycine-Modified Co-MOF Pervaporation Membrane to Enhance Water Transporting.

Cobalt-based metal-organic frameworks (Co-MOFs) with a two-dimensional layered morphology have received increasing attention for pervaporation due to their stability and hydrophilic properties. Using amino glycine (Gly) as a cross-linking agent, the Co-MOF ultrathin two-dimensional membrane doped with organic filler sodium alginate (SA) with the "brick-mixed-sand" structure was proposed. Polyacrylonitrile (PAN) was selected as the support layer of the hybrid membrane. The introduction of Gly efficiently solved the nanomaterial stacking problem and controllably adjusted the interlayer spacing between the nanosheets, which demonstrated good performance for ethanol dehydration. The results of this experimental research showed that the total flux of alcohol/water (9:1) separation by Gly-Co-MOF-SA/PAN hybrid membranes reached 1902 g m-2 h-1, which was 67% higher than that of the pure SA membranes. The "brick-mixed-sand" lamellar dense morphology of Gly-Co-MOF not only enhances membrane hydrophilicity but also provides effective channels for the rapid transport of water, which is expected to be used for the dehydration of organic solvents.

A rotational spectroscopy study of microsolvation effects on intramolecular proton transfer in trifluoroacetylacetone-(H2O)1-3.

Trifluoroacetylacetone (TFAA) has two enol forms, which can switch to each other via proton transfer. While much attention has been paid to their conformational preferences, the influence of microsolvation on regulating the proton position remains unexplored. Herein, we report the rotational spectra of trifluoroacetylacetone-(water)n (n = 1-3) investigated by chirped pulse Fourier transform microwave spectroscopy in the 2-8 GHz frequency range. Two conformers were identified for both TFAA-H2O and TFAA-(H2O)2, while only one conformer was characterized for TFAA-(H2O)3. The results indicate that water binding on the CH3 side stabilizes the enolF form, whereas water binding on the CF3 side stabilizes the enolH form. The enolF form predominates over the enolH form in these hydrated complexes, which contrasts with the fact that only enolH exists in isolated TFAA. EnolH becomes preferred only when water inserts itself into the intramolecular hydrogen bond. Instanton theory calculations reveal that the proton transfer reaction is dominated by quantum tunneling at low temperatures, leading to the stable existence of only one enol form in each configuration of the hydrated clusters.

Hydrogen-Bonded Complex of the Parent Phosphinidene.

The diatomic molecule PH is very reactive, and it serves as the parent compound for phosphinidenes featuring a monovalent phosphorus atom. Herein, we report the characterization and reactivity of a rare hydrogen-bonded complex of PH. Specifically, the molecular complex between PH and HCl has been generated by photolysis of chlorophosphine (H2PCl) at 254 nm in a solid Ar-matrix at 10 K. The IR spectrum of the complex HP⋅⋅⋅HCl and quantum chemical calculations at the UCCSD(T)-F12a/haTZ level consistently prove that the phosphorus atom acts as a hydrogen bond acceptor with a binding energy (D0) of -0.6 kcal mol-1. In line with the observed absorption at 341 nm for the binary complex, the triplet phosphinidene PH undergoes prototype H-Cl bond insertion by reformation of H2PCl upon photoexcitation at 365 nm. However, this hydrogen-bonded complex is unstable in the presence of N2 and HCl, as both molecules prefers stronger interactions with HCl than PH in the observed complexes HP⋅⋅⋅HCl⋅⋅⋅N2 and HP⋅⋅⋅2HCl.

Unveiling the Role of Water on π-π Stacking Through Microwave Spectroscopy of (Thiophene)2-(Water)1-2 Clusters.

There has been an ongoing debate about whether water enhances or hinders π-π stacking, a phenomenon crucial in various biological and chemical systems. In this study, the influence of water on π-π stacking is investigated by microwave spectroscopic observation of gas-phase hydrated clusters of thiophene dimers. Two isomers of (C4H4S)2-H2O and two isomers of (C4H4S)2-(H2O)2 have been unambiguously identified. These identifications are supported by quantum chemistry calculations and isotopic measurements. In each of these conformations, water molecules are situated between aromatic pairs, forming distinctive interactions. Water molecules engage with thiophene molecules either as hydrogen bond donors through OH···π interactions or as hydrogen bond acceptors through CH···O interactions. The energy decomposition analysis indicates that the bonding pattern of water molecules significantly affects the π···π interactions between aromatic rings. These findings offer valuable structural insights into the role of water in shaping π-π stacking.

Dynamic functional network connectivity based on spatial source phase maps of complex-valued fMRI data: Application to schizophrenia.

BACKGROUND: Dynamic spatial functional network connectivity (dsFNC) has shown advantages in detecting functional alterations impacted by mental disorders using magnitude-only fMRI data. However, complete fMRI data are complex-valued with unique and useful phase information. METHODS: We propose dsFNC of spatial source phase (SSP) maps, derived from complex-valued fMRI data (named SSP-dsFNC), to capture the dynamics elicited by the phase. We compute mutual information for connectivity quantification, employ statistical analysis and Markov chains to assess dynamics, ultimately classifying schizophrenia patients (SZs) and healthy controls (HCs) based on connectivity variance and Markov chain state transitions across windows. RESULTS: SSP-dsFNC yielded greater dynamics and more significant HC-SZ differences, due to the use of complete brain information from complex-valued fMRI data. COMPARISON WITH EXISTING METHODS: Compared with magnitude-dsFNC, SSP-dsFNC detected additional and meaningful connections across windows (e.g., for right frontal parietal) and achieved 14.6% higher accuracy for classifying HCs and SZs. CONCLUSIONS: This work provides new evidence about how SSP-dsFNC could be impacted by schizophrenia, and this information could be used to identify potential imaging biomarkers for psychotic diagnosis.

Interaction of Phytohormones and External Environmental Factors in the Regulation of the Bud Dormancy in Woody Plants.

Bud dormancy and release are essential phenomena that greatly assist in adapting to adverse growing conditions and promoting the holistic growth and development of perennial plants. The dormancy and release process of buds in temperate perennial trees involves complex interactions between physiological and biochemical processes influenced by various environmental factors, representing a meticulously orchestrated life cycle. In this review, we summarize the role of phytohormones and their crosstalk in the establishment and release of bud dormancy. External environmental factors, such as light and temperature, play a crucial role in regulating bud germination. We also highlight the mechanisms of how light and temperature are involved in the regulation of bud dormancy by modulating phytohormones. Moreover, the role of nutrient factors, including sugar, in regulating bud dormancy is also discussed. This review provides a foundation for enhancing our understanding of plant growth and development patterns, fostering agricultural production, and exploring plant adaptive responses to adversity.

Multi-omics study identifies that PICK1 deficiency causes male infertility by inhibiting vesicle trafficking in Sertoli cells.

BACKGROUND: Infertility affects approximately 10-15% of reproductive-age men worldwide, and genetic causes play a role in one-third of cases. As a Bin-Amphiphysin-Rvs (BAR) domain protein, protein interacting with C-kinase 1 (PICK1) deficiency could lead to impairment of acrosome maturation. However, its effects on auxiliary germ cells such as Sertoli cells are unknown. PURPOSE: The present work was aimed to use multi-omics analysis to research the effects of PICK1 deficiency on Sertoli cells and to identify effective biomarkers to distinguish fertile males from infertile males caused by PICK1 deficiency. METHODS: Whole-exome sequencing (WES) was performed on 20 infertility patients with oligozoospermia to identify pathogenic PICK1 mutations. Multi-omics analysis of a PICK1 knockout (KO) mouse model was utilized to identify pathogenic mechanism. Animal and cell function experiments of Sertoli cell-specific PICK1 KO mouse were performed to verify the functional impairment of Sertoli cells. RESULTS: Two loss-of-function deletion mutations c.358delA and c.364delA in PICK1 resulting in transcription loss of BAR functional domain were identified in infertility patients with a specific decrease in serum inhibin B, indicating functional impairment of Sertoli cells. Multi-omics analysis of PICK1 KO mouse illustrated that targeted genes of differentially expressed microRNAs and mRNAs are significantly enriched in the negative regulatory role in the vesicle trafficking pathway, while metabolomics analysis showed that the metabolism of amino acids, lipids, cofactors, vitamins, and endocrine factors changed. The phenotype of PICK1 KO mouse showed a reduction in testis volume, a decreased number of mature spermatozoa and impaired secretory function of Sertoli cells. In vitro experiments confirmed that the expression of growth factors secreted by Sertoli cells in PICK1 conditional KO mouse such as Bone morphogenetic protein 4 (BMP4) and Fibroblast growth factor 2 (FGF2) were decreased. CONCLUSIONS: Our study attributed male infertility caused by PICK1 deficiency to impaired vesicle-related secretory function of Sertoli cells and identified a variety of significant candidate biomarkers for male infertility induced by PICK1 deficiency.

Rapid Construction of Caffeic Acid/p-Phenylenediamine Antifouling Hydrophilic Coating on a PVDF Membrane for Emulsion Separation.

The current methods of constructing modification strategies for hydrophilic membranes are time-consuming, complex in operation, and poor in universality, which limit their application on membranes. In this work, inspired by the adhesion properties and versatility of caffeic acid (CA) and p-phenylenediamine (PPDA), a simple, rapid, and universal method was designed for the separation of oil-in-water emulsion by preparing a stable hydrophilic coating separation membrane. The preparation time of the membrane was shortened to 40 min. The developed PVDF-PCA/PPDA membrane showed superhydrophilic and underwater superoleophobic properties. When applied to petroleum ether-in-water emulsion, isooctane-in-water emulsion, and dodecane-in-water emulsion separation, the oil rejection was more than 99.0%. In the circulating separation of 10 g/L soybean oil-in-water emulsion, the oil rejection was more than 99.3%, and the highest flux was 1036 L·m-2·h-1. The prepared PVDF-PCA/PPDA membrane performed well in the separation test of oily wastewater. The proposed strategy is simple and rapid; it may become a universal method for preparing membranes with super strong antifouling properties against viscous oil and accelerate the research progress of membrane separation of oil-in-water emulsions.

Denoising brain networks using a fixed mathematical phase change in independent component analysis of magnitude-only fMRI data.

Brain networks extracted by independent component analysis (ICA) from magnitude-only fMRI data are usually denoised using various amplitude-based thresholds. By contrast, spatial source phase (SSP) or the phase information of ICA brain networks extracted from complex-valued fMRI data, has provided a simple yet effective way to perform the denoising using a fixed phase change. In this work, we extend the approach to magnitude-only fMRI data to avoid testing various amplitude thresholds for denoising magnitude maps extracted by ICA, as most studies do not save the complex-valued data. The main idea is to generate a mathematical SSP map for a magnitude map using a mapping framework, and the mapping framework is built using complex-valued fMRI data with a known SSP map. Here we leverage the fact that the phase map derived from phase fMRI data has similar phase information to the SSP map. After verifying the use of the magnitude data of complex-valued fMRI, this framework is generalized to work with magnitude-only data, allowing use of our approach even without the availability of the corresponding phase fMRI datasets. We test the proposed method using both simulated and experimental fMRI data including complex-valued data from University of New Mexico and magnitude-only data from Human Connectome Project. The results provide evidence that the mathematical SSP denoising with a fixed phase change is effective for denoising spatial maps from magnitude-only fMRI data in terms of retaining more BOLD-related activity and fewer unwanted voxels, compared with amplitude-based thresholding. The proposed method provides a unified and efficient SSP approach to denoise ICA brain networks in fMRI data.

UV-B promotes flavonoid biosynthesis in Ginkgo biloba by inducing the GbHY5-GbMYB1-GbFLS module.

Ginkgo biloba (ginkgo) leaves have medicinal value due to their high levels of secondary metabolites, such as flavonoids. We found that the flavonoid content in ginkgo leaves increases significantly at high altitudes (Qinghai-Tibet Plateau). Considering that high UV-B radiation is among the key environmental characteristics of the Qinghai-Tibet Plateau, we carried out simulated UV-B treatments on ginkgo seedlings and found that the flavonoid content of the leaves increased significantly following the treatments. Combined with results from our previous studies, we determined that the transcription factor GbHY5 may play a key role in responses to UV-B radiation. Overexpression of GbHY5 significantly promoted the accumulation of flavonoids in both ginkgo callus and Arabidopsis thaliana. Furthermore, yeast two-hybrid and real-time quantitative PCR showed that GbHY5 promoted the expression of GbMYB1 by interacting with GbMYB1 protein. Overexpression of GbMYB1 in ginkgo callus and A. thaliana also significantly promoted flavonoid biosynthesis. GbFLS encodes a key enzyme in flavonoid biosynthesis, and its promoter has binding elements of GbHY5 and GbMYB1. A dual-luciferase reporter assay indicated that while GbHY5 and GbMYB1 activated the expression of GbFLS individually, their co-expression achieved greater activation. Our analyses reveal the molecular mechanisms by which the UV-B-induced GbHY5-GbMYB1-GbFLS module promotes flavonoid biosynthesis in ginkgo, and they provide insight into the use of UV-B radiation to enhance the flavonoid content of ginkgo leaves.

A proximity labeling strategy enables proteomic analysis of inter-organelle membrane contacts.

Inter-organelle membrane contacts are highly dynamic and act as central hubs for many biological processes, but the protein compositions remain largely unknown due to the lack of efficient tools. Here, we developed BiFCPL to analyze the contact proteome in living cells by a bimolecular fluorescence complementation (BiFC)-based proximity labeling (PL) strategy. BiFCPL was applied to study mitochondria-endoplasmic reticulum contacts (MERCs) and mitochondria-lipid droplet (LD) contacts. We identified 403 highly confident MERC proteins, including many transiently resident proteins and potential tethers. Moreover, we demonstrated that mitochondria-LD contacts are sensitive to nutrient status. A comparative proteomic analysis revealed that 60 proteins are up- or downregulated at contact sites under metabolic challenge. We verified that SQLE, an enzyme for cholesterol synthesis, accumulates at mitochondria-LD contact sites probably to utilize local ATP for cholesterol synthesis. This work provides an efficient method to identify key proteins at inter-organelle membrane contacts in living cells.

Rotational Spectroscopy Probes Lone Pair···π-Hole Interactions in Hexafluorobenzene-Tertiary Alkylamines Complexes.

We employed microwave spectroscopy to investigate the 1:1 complexes of hexafluorobenzene with trimethylamine and quinuclidine, respectively. These complexes exhibit a C3v symmetry and are stabilized by nitrogen lone pair···π-hole interactions along the C3 axes. The N···π-center distances were determined to be 3.110(1) and 3.040(2) Å, respectively, which are shorter than that of hexafluorobenzene-ammonia at 3.2685(3) Å. Additionally, the strength of the intermolecular interaction increases with cluster size. While it was initially expected that the electron-donating effect of alkyl groups was responsible for changing the N···π interaction, the symmetry-adapted perturbation theory analysis revealed that, from hexafluorobenzene-ammonia to both hexafluorobenzene-alkylamines, electrostatic interaction actually decreases while dispersion interaction increases and becomes dominant. Interestingly, dispersion interaction decreases while electrostatic interaction increases from C6F6-N(CH3)3 to C6F6-NC7H13. The splitting pattern of the spectra indicates hexafluorobenzene rotates freely relative to its partners along the axis of the N···π-hole interactions.

Risk factors for difficult mask ventilation and difficult intubation among patients undergoing pharyngeal and laryngeal surgery.

Background: The prediction of difficult mask ventilation (DMV) and difficult intubation (DI) are key questions in anesthesia fields. DMV or DI related to pharyngeal and laryngeal diseases are a special kind of difficult airways. However, there is a lack of risk factors for prediction. Methods: This study retrospectively collected data from patients who were admitted to the Eye & ENT Hospital of Fudan University from May 2014 to May 2018 and underwent laryngopharyngeal surgery under general anesthesia. Results: A total of 126 patients were included. Twenty patients suffered from DMV. Preoperative laryngeal obstruction classification (OR = 7.46, 95% CI: 2.56-21.76, P < 0.001) and airway patency after sevoflurane inhalation (OR = 10.96, 95% CI: 2.70-44.43, p = 0.001) were independently associated with DMV. Seventy-six patients could be intubated at the first attempt. Preoperative laryngeal obstruction grade (OR = 0.28, 95% CI: 0.13-0.62, P = 0.002), neoplasm size (OR = 0.43, 95% CI: 0.22-0.82, P = 0.011), and airway patency after sevoflurane inhalation (OR = 0.14, 95% CI: 0.05-0.36, P < 0.001) were independently associated with first-attempt successful intubation. Conclusion: Among patients with pharyngeal and laryngeal diseases, the degree of laryngeal obstruction before the operation and the degree of airway obstruction after inhaling sevoflurane are the risk factors of DMV. The degree of laryngeal obstruction before the operation, airway obstruction after inhaling sevoflurane, and the neoplasm size are the risk factors of DI.

Genome-Wide Identification, Evolutionary and Functional Analyses of WRKY Family Members in Ginkgo biloba.

WRKY transcription factors (TFs) are one of the largest families in plants which play essential roles in plant growth and stress response. Ginkgo biloba is a living fossil that has remained essentially unchanged for more than 200 million years, and now has become widespread worldwide due to the medicinal active ingredients in its leaves. Here, 37 WRKY genes were identified, which were distributed randomly in nine chromosomes of G. biloba. Results of the phylogenetic analysis indicated that the GbWRKY could be divided into three groups. Furthermore, the expression patterns of GbWRKY genes were analyzed. Gene expression profiling and qRT-PCR revealed that different members of GbWRKY have different spatiotemporal expression patterns in different abiotic stresses. Most of the GbWRKY genes can respond to UV-B radiation, drought, high temperature and salt treatment. Meanwhile, all GbWRKY members performed phylogenetic tree analyses with the WRKY proteins of other species which were known to be associated with abiotic stress. The result suggested that GbWRKY may play a crucial role in regulating multiple stress tolerances. Additionally, GbWRKY13 and GbWRKY37 were all located in the nucleus, while GbWRKY15 was located in the nucleus and cytomembrane.