Development of transgenic Paulownia trees expressing antimicrobial thionin genes for enhanced resistance to fungal infections using chitosan nanoparticles.

There is an increasing focus on genetically altering Paulownia trees to enhance their resistance against fungal infections, given their rapid growth and quality wood production. The aim of this research was to establish a technique for incorporating two antimicrobial thionin genes, namely thionin-60 (thio-60) and thionin-63 (thio-63), into Paulownia tomentosa and Paulownia hybrid 9501 through the utilization of chitosan nanoparticles. The outcomes revealed the successful gene transfer into Paulownia trees utilizing chitosan nanoparticles. The effectiveness of thionin proteins against plant pathogens Fusarium and Aspergillus was examined, with a specific focus on Fusarium equiseti due to limited available data. In non-transgenic Paulownia species, the leaf weight inhibition percentage varied from 25 to 36 %, whereas in transgenic species, it ranged from 22 to 7 %. In general, Paulownia species expressing thio-60 displayed increased resistance to F. equiseti, while those expressing thio-63 exhibited heightened resistance to A. niger infection. The thionin proteins displayed a strong affinity for the phospholipid bilayer of the fungal cell membrane, demonstrating their capability to disrupt its structure. The transgenic plants created through this technique showed increased resistance to fungal infections. Thionin-60 demonstrated superior antifungal properties in comparison to thio-63, being more effective at disturbing the fungal cell membrane. These findings indicate that thio-60 holds potential as a novel antifungal agent and presents a promising approach for enhancing the antimicrobial traits of genetically modified Paulownia trees.

Antiproliferative and cytotoxic activities of C-Geranylated flavonoids from Paulownia tomentosa Steud. Fruit.

Prenylated or geranylated flavonoids have been studied for their promising antiproliferative and cytotoxic activities. Twelve natural geranylated flavonoids (1-12) were isolated from the fruit of Paulownia tomentosa Steud. Their structures were elucidated using UV and IR spectroscopy, mass spectrometry, and 1D and 2D NMR spectroscopy. The absolute configurations were determined using NMR and circular dichroism. Seven of the compounds were characterized as new geranylated derivatives isolated from a natural source for the first time, namely 3'-O-methyl-5'-hydroxyisodiplacone (3), paulodiplacone A (5), tomentone II (6), tomentone B (7), tomentodiplacone P (8), paulodiplacone B (9), and tomentoflavone A (12). After 24 h of incubation at concentrations in the range 1-30 µM, the isolated compounds were tested for their antiproliferative and cytotoxic potentials against the human monocytic leukaemia cell line THP-1, using WST-1 and LDH assays, respectively. Almost all of the test compounds induced a concentration-dependent reduction in the metabolic activity of THP-1 cells and a concentration-dependent reduction in the cell viability. Diplacone (1) was the most potent antiproliferative and cytotoxic agent (IC50 9.31 ± 0.72 µM, LC50 18.01 ± 1.19 µM). 3'-O-Methyl-5'-hydroxydiplacone (2) showed relatively strong antiproliferative effect (IC50 12.61 ± 0.90 µM) and weaker cytotoxic activity (LC50 > 30 µM), indicating that it may serve as a potential lead compound for further testing. The structure-activity relationship for the 12 isolated compounds is discussed.

Comparative proteomic analysis of autotetraploid and diploid Paulownia tomentosa reveals proteins associated with superior photosynthetic characteristics and stress adaptability in autotetraploid Paulownia.

To enlarge the germplasm resource of Paulownia plants, we used colchicine to induce autotetraploid Paulownia tomentosa, as reported previously. Compared with its diploid progenitor, autotetraploid P. tomentosa exhibits better photosynthetic characteristics and higher stress resistance. However, the underlying mechanism for its predominant characteristics has not been determined at the proteome level. In this study, isobaric tag for relative and absolute quantitation coupled with liquid chromatography-tandem mass spectrometry was employed to compare proteomic changes between autotetraploid and diploid P. tomentosa. A total of 1427 proteins were identified in our study, of which 130 proteins were differentially expressed between autotetraploid and diploid P. tomentosa. Functional analysis of differentially expressed proteins revealed that photosynthesis-related proteins and stress-responsive proteins were significantly enriched among the differentially expressed proteins, suggesting they may be responsible for the photosynthetic characteristics and stress adaptability of autotetraploid P. tomentosa. The correlation analysis between transcriptome and proteome data revealed that only 15 (11.5%) of the differentially expressed proteins had corresponding differentially expressed unigenes between diploid and autotetraploid P. tomentosa. These results indicated that there was a limited correlation between the differentially expressed proteins and the previously reported differentially expressed unigenes. This work provides new clues to better understand the superior traits in autotetraploid P. tomentosa and lays a theoretical foundation for developing Paulownia breeding strategies in the future.

Phytochemical profile of Paulownia tomentosa (Thunb). Steud.

Paulownia tomentosa, a member of the plant family Paulowniaceae and a rich source of biologically active secondary metabolites, is traditionally used in Chinese herbal medicine. Flavonoids, lignans, phenolic glycosides, quinones, terpenoids, glycerides, phenolic acids, and miscellaneous other compounds have been isolated from different parts of P. tomentosa plant. Recent interest in this species has focused on isolating and identifying of prenylated flavonoids, that exhibit potent antioxidant, antibacterial, and antiphlogistic activities and inhibit severe acute respiratory syndrome coronavirus papain-like protease. They show cytotoxic activity against various human cancer cell lines and inhibit the effects of human cholinesterase, butyrylcholinesterase, and bacterial neuraminidases. Most of the compounds considered here have never been isolated from any other species of plant. This review summarizes the information about the isolated compounds that are active, their bioactivities, and the structure-activity relationships that have been worked out for them.

Perspectives on antimicrobial properties of Paulownia tomentosa Steud. fruit products in the control of Staphylococcus aureus infections.

ETHNOPHARMACOLOGICAL RELEVANCE: Paulownia tomentosa Steud. (P. tomentosa) is a medium-sized tree traditionally used in Chinese folk medicine for the treatment of infectious diseases. It is a rich source of prenylated phenolic compounds that have been extensively studied for their promising biological activities. AIM OF THE STUDY: Due to the increasing development of antibiotic resistance, our study investigated plant-derived natural products from the fruits of P. tomentosa that could control Staphylococcus aureus infections with novel targets/modes of action and reduce antimicrobial resistance. MATERIALS AND METHODS: The ethanolic extract was fractionated and detected by liquid chromatography. The antistaphylococcal effects of the plant formulations were studied in detail in vitro by various biological methods, including microdilution methods for minimum inhibitory concentration (MIC), the checkerboard titration technique for synergy assay, fluorescence measurements for membrane disruption experiments, autoinducer-2-mediated bioassay for quorum sensing inhibition, and counting of colony-forming units for relative adhesion. Morphology was examined by transmission electron microscopy. RESULTS: Total ethanolic extract and chloroform fraction showed MICs of 128 and 32 µg/mL, respectively. Diplacol, diplacone, and 3'-O-methyl-5'-hydroxydiplacone inhibited S. aureus growth in the range of 8-16 µg/mL. Synergistic potential was shown in combination with mupirocin and fusidic acid. The ethanolic extract and the chloroform fraction destroyed the cell membranes by 91.61% and 79.46%, respectively, while the pure compounds were less active. The ethanolic extract and the pure compounds reduced the number of adhered cells to 47.33-10.26% compared to the untreated control. All tested plant formulations, except diplacone, inhibited quorum sensing of S. aureus. Transmission electron microscopy showed deformation of S. aureus cells. CONCLUSIONS: The products from the fruit of P. tomentosa showed antimicrobial properties against S. aureus alone and in combination with antibiotics. By affecting intracellular targets, geranylated flavonoids proposed novel approaches in the control of staphylococcal infections.

A potential host and virus targeting tool against COVID-19: Chemical characterization, antiviral, cytoprotective, antioxidant, respiratory smooth muscle relaxant effects of Paulownia tomentosa Steud.

COronaVIrus Disease 2019 (COVID-19) is a newly emerging infectious disease that spread across the world, caused by the novel coronavirus Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS-CoV-2). Despite the advancements in science that led to the creation of the vaccine, there is still an urgent need for new antiviral drugs effective against SARS-CoV-2. This study aimed to investigate the antiviral effect of Paulownia tomentosa Steud extract against SARS-CoV-2 and to evaluate its antioxidant properties, including respiratory smooth muscle relaxant effects. Our results showed that P. tomentosa extract can inhibit viral replication by directly interacting with both the 3-chymotrypsin-like protease and spike protein. In addition, the phyto complex does not reduce lung epithelial cell viability and exerts a protective action in those cells damaged by tert-butyl hydroperoxide , a toxic agent able to alter cells' functions via increased oxidative stress. These data suggest the potential role of P. tomentosa extract in COVID-19 treatment, since this extract is able to act both as an antiviral and a cytoprotective agent in vitro.

Structural characterization and adjuvant action of Paulownia tomentosa flower polysaccharide on the immune responses to classical swine fever vaccine in mice.

Paulownia tomentosa flower polysaccharide (PTFP) from dried cultured P. tomentosa flowers, is widely known for its immunomodulatory activities. Here, PTFP was extracted from Paulownia tomentosa flower using hot water extraction, followed by ethanol precipitation methods. Structural characterization of PTFP was revealed by scanning electron microscope, high-performance anion-exchange chromatography, gel chromatography, ultraviolet and infrared spectral. Meanwhile, adjuvant action of PTFT on the immune responses to classical swine fever vaccine in mice was evaluated to further proclaim the immune regulatory effect of PTFP. The results showed that PTFP was a type of heteropolysaccharide with a dense, rough surface and high molecular weight (667.02 kDa), mainly composed of glucose (30.93%), rhamnose (29.99%), galactose (15.66%), arabinose (6.95%), mannose (5.52%), and xylose (4.80%). The results of gel chromatography suggested that the molecular configuration of PTFP may be a spherical structure. The infrared spectrum results confirmed that the functional groups and chemical bond of PTFP contained -OH, O-H, C-H, C=O, C-O, etc. Moreover, PTFP exhibited obvious immune enhancement effect by improving concanavalin A (ConA), lipopolysaccharide (LPS), and CSFV E2-stimulated splenocyte growth and natural killer cell activity in CSFV-immunized mice. Similarly, the titers of CSFV E2-specific IgG, IgG1, IgG2a, and IgG2b antibodies and IFN-γ and IL-10 levels in CSFV-immunized mice were distinctly increased by PTFP treatment. Overall, PTFP was a macromolecular heteropolysaccharide primarily containing glucose and rhamnose, and possessed the auxiliary effect of immune enhancement on the immune responses to classical swine fever vaccine.

Impact of Enterococcus italicus ONU547 on the growth and acclimatization of micropropagated Rubus fruticosus L. and Paulownia tomentosa Steud. plants to ex vitro conditions.

Clonal micropropagation is an effective method for plant reproduction, applicable in both scientific and industrial domains. However, a significant number of microclones are lost during the ex vitro acclimatization process. To address this, the introduction of beneficial microorganisms into the rhizosphere of micropropagated plants could have a positive effect on the survival rates and external characteristics of acclimatized plantlets. The aim of this study was to determine the protective and growth-promoting potential of Enterococcus italicus ONU547 and its effect on micropropagated plants during acclimatization. The antagonistic activity of the bacteria was determined using the agar block method. Lepidium sativum L. seeds were inoculated with bacterial suspensions at concentrations of 106, 107, and 108 CFU/ml. Subsequently, the roots of the microclones were treated with suspensions of 106 and 107 CFU/ml, and biometric characteristics were measured. The results demonstrated antagonistic properties against various phytopathogenic fungi, including Aspergillus niger, Cladosporium cladosporioides, Alternaria alternata, Alternaria tenuissima, Rhizoctonia cerealis, Penicillium expansum, and Paecilomyces variotii. Inoculation of L. sativum L. seeds resulted in improved germination rates, increased root numbers, and enhanced root and shoot lengths. Similarly, the effects of the studied bacteria on Rubus fruticosus L. and Paulownia tomentosa Steud. during the acclimatization stage led to higher survival rates, increased shoot lengths, greater node numbers, and larger leaf areas. A concentration of 107 CFU/ml was identified as optimal for inoculating the microclones. The findings indicate that E. italicus ONU547 holds promise for the inoculation of micropropagated plants during the acclimatization process. Further research is recommended to establish the specific interaction mechanisms between these bacteria and plants.

Multiple Plant Regeneration from Embryogenic Calli of Paulownia tomentosa (Thunb.) Steud.

The aim of this paper was to study the effect of plant growth regulators on callus induction and in vitro morphogenesis using various explants of Paulownia tomentosa to develop an efficient plant regeneration protocol. Different plant organ sections (leaves, apical shoot tips, petals, nodes, and internodes) were cultured as explants to identify the best in vitro explants responsive to callus induction and plant regeneration. Explants were cultivated on MS media supplemented with different concentrations of plant growth regulators (TDZ (Thidiazuron), BAP (6-Benzylaminopurine), kinetin, and NAA (1-Naphthaleneacetic acid). It was discovered that the addition of TDZ and NAA stimulated the induction of somatic embryogenesis. It was discovered that the MS medium with the combination of plant growth regulators BAP (35.5 µM) and NAA (5.4 µM) with the addition of 30.0 g/L maltose, 500.0 mg/L casein hydrolysate, and 250.0 mg/L L-proline was optimal for callus induction and multiple plant regeneration. The study of the regenerative capacity of various explants of Paulownia tomentosa in vitro showed that plant regeneration depends on the type of explant, and occurs in both ways, indirectly, through the formation of callus tissues and directly on the explant, without callus formation. As a result of this study, the efficient reproducible protocol of embryogenic callus formation and multiple shoot induction in vitro of Paulownia tomentosa was developed. This system provides a clear increase in the frequency of plant regeneration from 36.3 ± 3.4% to 38.6 ± 2.3% per embryogenic callus from leaves and apical shoot tips, respectively.

Characterization of a Translucent Material Produced from Paulownia tomentosa Using Peracetic Acid Delignification and Resin Infiltration.

Paulownia tomentosa, a tree species that allows for efficient production of translucent wood, was selected as an experimental wood species in this study, and a two-step process of delignification and polymer impregnation was performed. For delignification, 2-4 mm thick specimens were immersed in peracetic acid for 8 h. The delignified-wood specimens were impregnated using epoxy, a commercial transparent polymer. To identify the characteristics of the resulting translucent wood, the transmittance and haze of each type of wood section (cross- and tangential) were measured, while bending strength was measured using a universal testing machine. The translucent wood varied in properties according to the wood section, and the total transmittance and haze were 88.0% and 78.5% for the tangential section and 91.3% and 96.2% for the cross-section, respectively. For the bending strength, untreated wood showed values of approximately 4613.5 MPa modulus of elasticity (MOE), while the epoxy impregnation to improve the strength of the wood had increased the MOE up to approximately 6089.9 MPa, respectively. A comparative analysis was performed in this study with respect to the substitution of balsa, which is used widely in the production of translucent wood. The results are anticipated to serve as baseline data for the functionalization of translucent wood.

Phytoremediation of Soil Contaminated by Organochlorine Pesticides and Toxic Trace Elements: Prospects and Limitations of Paulownia tomentosa.

Paulownia tomentosa (Thunb.) Steud is a drought-resistant, low-maintenance and fast-growing energy crop that can withstand a wide range of climatic conditions, provides a high biomass yield (approximately 50 t DM ha-1 yr-1), and develops successfully in contaminated sites. In Kazakhstan, there are many historically contaminated sites polluted by a mixture of xenobiotics of organic and inorganic origin that need to be revitalised. Pilot-scale research evaluated the potential of P. tomentosa for the phytoremediation of soils historically contaminated with organochlorine pesticides (OCPs) and toxic trace elements (TTEs) to minimise their impact on the environment. Targeted soils from the obsolete pesticide stockpiles located in three villages of Talgar district, Almaty region, Kazakhstan, i.e., Amangeldy (soil A), Beskainar (soil B), and Kyzylkairat (soil K), were subjected to research. Twenty OCPs and eight TTEs (As, Cr, Co, Ni, Cu, Zn, Cd, and Pb) were detected in the soils. The phytoremediation potential of P. tomentosa was investigated for OCPs whose concentrations in the soils were significantly different (aldrin, endosulfans, endrin aldehyde, HCB, heptachlor, hexabromobenzene, keltan, methoxychlor, and γ-HCH) and for TTEs (Cu, Zn, and Cd) whose concentrations exceeded maximum permissible concentrations. Bioconcentration (BCF) and translocation (TLF) factors were used as indicators of the phytoremediation process. It was ensured that the uptake and translocation of contaminants by P. tomentosa was highly variable and depended on their properties and concentrations in soil. Besides the ability to bioconcentrate Cr, Ni, and Cu, P. tomentosa demonstrated very encouraging results in the accumulation of endosulfans, keltan, and methoxychlor and the phytoextraction of γ-HCH (TLFs of 1.9-9.9) and HCB (BCFs of 197-571). The results of the pilot trials support the need to further investigate the potential of P. tomentosa for phytoremediation on a field scale.

C-geranylated flavonoids from Paulownia tomentosa Steud. fruit as potential anti-inflammatory agents.

ETHNOPHARMACOLOGICAL RELEVANCE: Paulownia tomentosa Steud., a traditional Chinese medicinal plant, was used for many centuries in Chinese herbal medicine as a component of remedies for many illnesses, including inflammatory diseases. It is a rich source of phenolic compounds, mainly geranylated flavonoids, which are currently studied for their promising biological activities. AIM OF THE STUDY: The study aimed to isolate minor geranylated flavanones and flavones from P. tomentosa fruit and evaluate their cytotoxicity and possible anti-inflammatory effects in a cell-based model of inflammation. MATERIALS AND METHODS: Chromatographic separation of chloroform portion of the ethanolic extract of P. tomentosa fruit led to the isolation of twenty-seven flavonoids (1-27), twenty-six of them geranylated with different modifications and one non-geranylated flavanone, and two phenolic compounds. Compounds were identified using UV, IR, HRMS, NMR, and CD spectroscopy. Ten of these compounds (7-10, 12, 21, 22, 24, 25, and 27) were determined to be new flavonoid derivatives obtained from a natural source for the first time. Selected compounds were analyzed for cytotoxicity and anti-inflammatory potential to affect the activation of nuclear factor κB/activator protein 1 (NF-κB/AP-1) after lipopolysaccharide (LPS) stimulation. RESULTS: All the test compounds (1-21 and 23-26) reduced the activation of NF-κB/AP-1 24 h after the addition of LPS. Eight compounds (5, 14-18, 21, and 26) were more active than prednisone, a widely used anti-inflammatory drug. However, this effect was not seen significantly on the level of TNF-α and IL-1ß, which can be explained by the plurality of possible outcomes of activation of the NF-κB pathway in cells. CONCLUSIONS: Results of the presented study confirmed that constituents from traditional Chinese medicinal plant P. tomentosa Steud. have promising anti-inflammatory activities and can serve as a potential source of inspiration for new anti-inflammatory medications.

Paulownia Leaves as A New Feed Resource: Chemical Composition and Effects on Growth, Carcasses, Digestibility, Blood Biochemistry, and Intestinal Bacterial Populations of Growing Rabbits.

This experiment was conducted to study the effects of paulownia leaf meal (PLM) as a nontraditional feed on the growth, carcasses, digestibility, blood chemistry, and intestinal microbiota of growing rabbits. Sixty rabbits (5-weeks old) were randomly allotted to three dietary treatments containing three amounts of PLM (0%, 15%, and 30%). The results showed that PLM has a higher content of ether extract, organic matter, methionine, tyrosine, histidine, manganese, and zinc than alfalfa hay. Body weight gain decreased when 30% PLM was provided. The best feed conversion ratio was recorded in the rabbits fed 15% PLM. A notable increase in high-density lipoprotein levels with a significant decrease in low-density lipoprotein was noted in the rabbits fed the PLM diets. Total fungi and Enterobacteriaceae and total bacterial count in the feed were significantly reduced because of PLM. In the cecum, coliforms, Enterobacteriaceae species, and total bacterial count declined in the rabbits fed the PLM diets. Conclusively, up to 15% PLM can be used in rabbit diets without any deleterious effects on the performance, nutrient digestibility, and blood constituents. In addition, dietary inclusion of PLM has the potential to reduce cecal pathogenic bacteria in rabbits.

The enhanced immunological activity of Paulownia tomentosa flower polysaccharide on Newcastle disease vaccine in chicken.

The extracts of Paulownia tomentosa (P. tomentosa) exhibit multiple pharmacological activities. In the present study, P. tomentosa flower polysaccharides (PTFP) were extracted by water decoction and ethanol precipitation, and the immunologic modulations of PTFP against Newcastle disease (ND) vaccine was investigated in chickens. The results showed that in a certain range of concentrations, PTFP treatment can dose-dependently enhance lymphocyte proliferation. Then, 280 14-days-old chickens were randomly divided into seven groups, and vaccinated with ND vaccine except blank control (BC) group. At the first vaccination, chickens were orally administrated with PTFP at concentration ranging from 0 to 50 mg/kg once a day for 3 successive days, and the BC group was treated with physiological saline. The lymphocyte proliferation rate, serum antibody titer, and levels of interferon-γ (IFN-γ) were respectively measured on 7, 14, 21, and 28 days after the first vaccination. The results showed that PTFP at the suitable doses could significantly promote lymphocyte proliferation, enhance serum antibody titer, and improve serum IFN-γ concentrations. Taken together, these data indicated that PTFP could improve the immune efficacy against ND vaccine in chickens, and could be as the candidate of a new-type immune adjuvant.

Genome-wide identification and profiling of microRNAs in Paulownia tomentosa cambial tissues in response to seasonal changes.

MicroRNAs (miRNAs), a group of endogenous small non-coding RNAs, have been shown to play essential roles in the regulation of gene expression at the post-transcriptional level. Although Paulownia tomentosa is an ecologically and economically important timber species due to its rapid growth, few efforts have focused on small RNAs (sRNAs) in the cambial tissues during winter and summer transition. In the present study, we identified 33 known miRNA families and 29 novel miRNAs which include 20 putative novel miRNAs* in P. tomentosa cambial tissues during winter and summer transition. Through differential expression analysis, we showed that 15 known miRNAs and 8 novel miRNAs were preferentially abundant in certain stage of cambial tissues. Based on the P. tomentosa mRNA transcriptome database, 1667 and 78 potential targets were predicted for 29 known and 20 novel miRNAs, respectively and the predicted targets are mostly transcription factors and functional genes. The targets of these miRNAs were enriched in "metabolic process" and "transcription regulation" by using Gene Ontology enrichment analysis. In addition, KEGG pathway analyses revealed the involvement of miRNAs in starch and sucrose metabolism and plant-pathogen interaction metabolism pathways. Noticeably, qRT-PCR expression analysis demonstrated that 9 miRNAs and their targets were existed a negative correlation in P. tomentosa cambial tissues. This study is the first to examine known and novel miRNAs and their potential targets in P. tomentosa cambial tissues during winter and summer transition and identify several candidate genes potentially regulating cambial phase transition, and thus provide a framework for further understanding of miRNAs functions in the regulation of cambial phase transition and wood formation in trees.

Anti-inflammatory effect of stem bark of Paulownia tomentosa Steud. in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages and LPS-induced murine model of acute lung injury.

ETHNOPHARMACOLOGICAL RELEVANCE: The leaves, bark, and flowers of Paulownia tomentosa Steud. have been widely used as a traditional medicine in East Asia to treat inflammatory and infectious diseases. AIM OF THE STUDY: We investigated the protective effect of the methanol stem bark extract of P. tomentosa using an animal model of lipopolysaccharide (LPS)-induced acute lung injury (ALI). MATERIALS AND METHODS: The UPLC Q-TOF-MS profiles for the methanol extract of P. tomentosa stem bark showed that verbascoside and isoverbascoside were the predominant compounds. Raw 264.7 cells were used for inhibitory effects of cytokine production in vitro. C57BL/6N mice were administered intranasally with LPS (10µg/per mouse) to induce ALI. H&E staining was used to evaluate histological changes in the lung. RESULTS: Treatment with P. tomentosa stem bark extract (PTBE) suppressed the production of IL-6 and TNF-α in LPS-stimulated RAW 264.7 macrophages, and the recruitment of neutrophils and macrophages in the BALF of mice with LPS-induced ALI. PTBE also decreased the levels of reactive oxygen species (ROS) and pro-inflammatory cytokines in the BALF. PTBE reduced the levels of nitric oxide (NO) in the serum and of inducible nitric oxide synthase (iNOS) in the lung of ALI mice. PTBE also attenuated the infiltration of inflammatory cells and the expression of monocyte chemoattractant protein-1 (MCP-1) in the lung. In addition, PTBE suppressed the activation of NF-κB and the reduced expression of superoxide dismutase 3 (SOD3) in the lung. CONCLUSION: The results suggest that PTBE has a protective effect on LPS-induced ALI.

Drought stress-induced changes of microRNAs in diploid and autotetraploid Paulownia tomentosa.

Drought stress adversely affects plant productivity. Growth and timber production of Paulownia trees are limited under drought stress. Changes in gene expression patterns and miRNA in different ploidy of Paulownia tomentosa have been investigated. However, the responses of P. tomentosa to drought stress at the microRNA (miRNA) level have not been reported so far. To identify miRNA candidates and their target genes involved in the drought stress response in diploid and tetraploid P. tomentosa, four small RNA and four degradome libraries from diploid and autotetraploid P. tomentosa under normal and drought stress conditions were constructed and sequenced. A total of 41 conserved and 90 novel miRNAs were identified. Among these miRNAs, 67 (26 conserved and 41 novel) and 53 (six conserved and 47 novel) were significantly differentially expressed in response to drought stress in diploid and autotetraploid P. tomentosa, respectively. Degradome analysis identified 356 candidate miRNA target genes that encoded proteins with functions that included plant defense, transcriptional regulation, and hormone metabolism. In particular, miR4 and miR156 were identified only in autotetraploid P. tomentosa under drought stress. These results will help us build a foundation for future studies of the biological functions of miRNA-mediated gene regulation in P. tomentosa.

Proteome Profiling of Paulownia Seedlings Infected with Phytoplasma.

Phytoplasma is an insect-transmitted pathogen that causes witches' broom disease in many plants. Paulownia witches' broom is one of the most destructive diseases threatening Paulownia production. The molecular mechanisms associated with this disease have been investigated by transcriptome sequencing, but changes in protein abundance have not been investigated with isobaric tags for relative and absolute quantitation. Previous results have shown that methyl methane sulfonate (MMS) can help Paulownia seedlings recover from the symptoms of witches' broom and reinstate a healthy morphology. In this study, a transcriptomic-assisted proteomic technique was used to analyze the protein changes in phytoplasma-infected Paulownia tomentosa seedlings, phytoplasma-infected seedlings treated with 20 and 60 mg·L-1 MMS, and healthy seedlings. A total of 2,051 proteins were obtained, 879 of which were found to be differentially abundant in pairwise comparisons between the sample groups. Among the differentially abundant proteins, 43 were related to Paulownia witches' broom disease and many of them were annotated to be involved in photosynthesis, expression of dwarf symptom, energy production, and cell signal pathways.

Two complete chloroplast genome sequences of genus Paulownia (Paulowniaceae): Paulownia coreana and P. tomentosa.

The nucleotide sequence of the two chloroplast (cp) genomes from Paulownia coreana and P. tomentosa are the first to be completed in genus Paulownia of family Paulowniaceae. The structure of two Paulownia cp genomes shows similar characteristic with general cp genome of angiosperms. The lengths of two cp genomes are 154,545 bp and 154,540 bp, respectively. The cp genomes are divided into LSC region (85,241 bp and 85,236 bp) and SSC region (17,736 bp and 17,736 bp) by two IR regions (25,784 bp and 25,784 bp). Both of two cp genomes contain 113 genes (79 protein coding genes, 30 tRNA genes and 4 rRNA genes), eight protein-coding genes, seven tRNA genes and four rRNA genes duplicated in the IR regions. Similar to the general cp genome of angiosperms, 18 of the genes in the two cp genomes have one or two introns. The overall A-T contents of two genomes are 62.0% which is similar with general angiosperms. The A-T content in the non-coding (64.6%) is higher than in the coding (60.1%) regions. Seventy-one and seventy simple sequence repeat (SSR) loci were identified in the P. coreana and P. tomentosa cp genomes, respectively. In phylogenetic analysis, genus Paulownia shows closed relationship with Lindenbergia philippensis of Orobanchaceae.

Changes in Transcript Related to Osmosis and Intracellular Ion Homeostasis in Paulownia tomentosa under Salt Stress.

Paulownia tomentosa is an important economic and greening tree species that is cultivated widely, including salt environment. Our previous studies indicated its autotetraploid induced by colchicine showed better stress tolerance, but the underlying molecular mechanism related to ploidy and salt stress is still unclear. To investigate this issue, physiological measurements and transcriptome profiling of diploid and autotetraploid plants untreated and treated with NaCl were performed. Through the comparisons among four accessions, for one thing, we found different physiological changes between diploid and autotetraploid P. tomentosa; for another, and we detected many differentially expressed unigenes involved in salt stress response. These differentially expressed unigenes were assigned to several metabolic pathways, including "plant hormone signal transduction," "RNA transporter," "protein processing in endoplasmic reticulum," and "plant-pathogen interaction," which constructed the complex regulatory network to maintain osmotic and intracellular ion homeostasis. Quantitative real-time polymerase chain reaction was used to confirm the expression patterns of 20 unigenes. The results establish the foundation for the genetic basis of salt tolerance in P. tomentosa, which in turn accelerates Paulownia breeding and expands available arable land.