The dual role of GoPGF reveals that the pigment glands are synthetic sites of gossypol in aerial parts of cotton.

Gossypol and the related terpenoids are stored in the pigment gland to protect cotton plants from biotic stresses, but little is known about the synthetic sites of these metabolites. Here, we showed that GoPGF, a key gene regulating gland formation, was expressed in gland cells and roots. The chromatin immunoprecipitation sequencing (ChIP-seq) analysis demonstrated that GoPGF targets GhJUB1 to regulate gland morphogenesis. RNA-sequencing (RNA-seq) showed high accumulation of gossypol biosynthetic genes in gland cells. Moreover, integrated analysis of the ChIP-seq and RNA-seq data revealed that GoPGF binds to the promoter of several gossypol biosynthetic genes. The cotton callus overexpressing GoPGF had dramatically increased the gossypol levels, indicating that GoPGF can directly activate the biosynthesis of gossypol. In addition, the gopgf mutant analysis revealed the existence of both GoPGF-dependent and -independent regulation of gossypol production in cotton roots. Our study revealed that the pigment glands are synthetic sites of gossypol in aerial parts of cotton and that GoPGF plays a dual role in regulating gland morphogenesis and gossypol biosynthesis. The study provides new insights for exploring the complex relationship between glands and the metabolites they store in cotton and other plant species.

Direct Enol Ether Metalation-Negishi Coupling Strategy To Prepare α-Heteroaryl Enol Ethers.

A robust direct enol ether metalation-Negishi coupling using heteroaryl halides catalyzed by the palladium-Cy-DPEPhos system is reported. This method, which was demonstrated with a broad substrate scope, is a highly complementary method to the existing Heck coupling of synthesizing challenging α-heteroaryl-α-alkoxy alkenes.

Efficient genome editing in cotton using the virus-mediated CRISPR/Cas9 and grafting system.

KEY MESSAGE: The extensive application of CRISPR in cotton was limited due to the labor-intensive transformation process. Thus, we here established a convenient method of CRISPR in cotton by CLCrV-mediated sgRNA delivery.

Profile of cotton flavonoids: Their composition and important roles in development and adaptation to adverse environments.

Cotton is a commercial crop that is cultivated in more than 50 countries. The production of cotton has severely diminished in recent years owing to adverse environments. Thus, it is a high priority of the cotton industry to produce resistant cultivars to prevent diminished cotton yields and quality. Flavonoids comprise one of the most important groups of phenolic metabolites in plants. However, the advantage and biological roles of flavonoids in cotton have yet not been studied in depth. In this study, we performed a widely targeted metabolic study and identified 190 flavonoids in cotton leaves that span seven different classes with flavones and flavonols as the dominant groups. Furthermore, flavanone-3-hydroxylase was cloned and silenced to knock down flavonoid production. The results show that the inhibition of flavonoid biosynthesis affects the growth and development of cotton and causes semi-dwarfing in cotton seedlings. We also revealed that the flavonoids contribute to cotton defense against ultraviolet radiation and Verticillium dahliae. Moreover, we discuss the promising role of flavonoids in cotton development and defense against biotic and abiotic stresses. This study provides valuable information to study the variety and biological functions of flavonoids in cotton and will help to profile the advantages of flavonoids in cotton breeding.

The Na+/H+ antiporter GbSOS1 interacts with SIP5 and regulates salt tolerance in Gossypium barbadense.

Cotton is a globally cultivated economic crop and is a major source of natural fiber and edible oil. However, cotton production is severely affected by salt stress. Although Salt Overly Sensitive 1 (SOS1) is a well-studied Na+/H+ antiporter in multiple plant species, little is known about its function and regulatory mechanism in cotton. Here, we cloned a salt-induced SOS1 from sea-island cotton. Real-time quantitative PCR analysis revealed that GbSOS1 was induced by multiple stresses and phytohormones. Silencing GbSOS1 through virus-induced gene silencing significantly reduced cotton resistance to high Na+ but mildly affected Li+ tolerance. On the other hand, overexpression of GbSOS1 enhanced salt tolerance in yeast, Arabidopsis, and cotton largely due to the ability to maintain Na+ homeostasis in protoplasts. Yeast-two-hybrid assays and bimolecular fluorescence complementation identified a novel protein interacting with GbSOS1 on the plasma membrane, which we named SOS Interaction Protein 5 (SIP5). We found that the SIP5 gene encoded an unknown protein localized on the cell membrane. Silencing SIP5 significantly increased cotton tolerance to salt, exhibited by less wilting and plant death under salt stress. Our results revealed that GbSOS1 is crucial for cotton survival in saline soil, and SIP5 is a potentially negative regulator of SOS1-mediated salt tolerance in cotton. Overall, this study provides a theoretical basis for elucidating the molecular mechanism of SOS1, and a candidate gene for breeding salt-tolerant crops.

Comparative proteomic analysis identified proteins and the phenylpropanoid biosynthesis pathway involved in the response to ABA treatment in cotton fiber development.

Abscisic acid (ABA) is a plant hormone that plays an important role in cotton fiber development. In this study, the physiological changes and proteomic profiles of cotton (Gossypium hirsutum) ovules were analyzed after 20 days of ABA or ABA inhibitor (ABAI) treatment. The results showed that compared to the control (CK), the fiber length was significantly decreased under ABA treatment and increased under ABAI treatment. Using a tandem mass tags-based quantitative technique, the proteomes of cotton ovules were comprehensively analyzed. A total of 7321 proteins were identified, of which 365 and 69 differentially accumulated proteins (DAPs) were identified in ABA versus CK and ABAI versus CK, respectively. Specifically, 345 and 20 DAPs were up- and down-regulated in the ABA group, and 65 and 4 DAPs were up- and down-regulated in the ABAI group, respectively. The DAPs in the ABA group were mainly enriched in the biosynthesis of secondary metabolites, phenylpropanoid biosynthesis and flavonoid secondary metabolism, whereas the DAPs in the ABAI group were mainly enriched in the indole alkaloid biosynthesis and phenylpropanoid biosynthesis pathways. Moreover, 9 proteins involved in phenylpropanoid biosynthesis were upregulated after ABA treatment, suggesting that this pathway might play important roles in the response to ABA, and 3 auxin-related proteins were upregulated, indicating that auxin might participate in the regulation of fiber development under ABAI treatment.

Colorful Conductive Threads for Wearable Electronics: Transparent Cu-Ag Nanonets.

Electronic textiles have been regarded as the basic building blocks for constructing a new generation of wearable electronics. However, the electronization of textiles often changes their original properties such as color, softness, glossiness, or flexibility. Here a rapid room-temperature fabrication method toward conductive colorful threads and fabrics with Ag-coated Cu (Cu-Ag) nanonets is demonstrated. Cu-Ag core-shell nanowires are produced through a one-pot synthesis followed by electroless deposition. According to the balance of draining and entraining forces, a fast dip-withdraw process in a volatile solution is developed to tightly wrap Cu-Ag nanonets onto the fibers of thread. The modified threads are not only conductive, but they also retain their original features with enhanced mechanical stability and dry-wash durability. Furthermore, various e-textile devices are fabricated such as a fabric heater, touch screen gloves, a wearable real-time temperature sensor, and warm fabrics against infrared thermal dissipation. These high quality and colorful conductive textiles will provide powerful materials for promoting next-generation applications in wearable electronics.

Towards n-type conductivity in hexagonal boron nitride.

Asymmetric transport characteristic in n- and p-type conductivity has long been a fundamental difficulty in wide bandgap semiconductors. Hexagonal boron nitride (h-BN) can achieve p-type conduction, however, the n-type conductivity still remains unavailable. Here, we demonstrate a concept of orbital split induced level engineering through sacrificial impurity coupling and the realization of efficient n-type transport in 2D h-BN monolayer. We find that the O 2pz orbital has both symmetry and energy matching to the Ge 4pz orbital, which promises a strong coupling. The introduction of side-by-side O to Ge donor can effectively push up the donor level by the formation of another sacrificial deep level. We discover that a Ge-O2 trimer brings the extremely shallow donor level and very low ionization energy. By low-pressure chemical vapor deposition method, we obtain the in-situ Ge-O doping in h-BN monolayer and successfully achieve both through-plane (~100 nA) and in-plane (~20 nA) n-type conduction. We fabricate a vertically-stacked n-hBN/p-GaN heterojunction and show distinct rectification characteristics. The sacrificial impurity coupling method provides a highly viable route to overcome the n-type limitation of h-BN and paves the way for the future 2D optoelectronic devices.

Screening and identification of α-glucosidase inhibitors from Cyclocarya paliurus leaves by ultrafiltration coupled with liquid chromatography-mass spectrometry and molecular docking.

Cyclocarya paliurus, as an important edible and medicinal product, has shown a good prospect in the prevention of diabetes mellitus (DM). However, it is unclear which active compounds derived from C. paliurus play a significant role in inhibiting α-glucosidase activity. In present study, affinity-based screening assay was developed to screen and identify potential α-glucosidase inhibitors from C. paliurus leaves based on affinity ultrafiltration coupled with ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS/MS) and molecular docking. After being enriched by D-101 macroporous resin, five eluent fractions with different polarity were obtained and their inhibitory activities on α-glucosidase were evaluated by an enzyme inhibition assay in vitro. The result showed that 70% ethanol fraction of C. paliurus leaves exhibited remarkable α-glucosidase inhibitory activity with the IC50 value of 17.81 µg/mL. The 70% ethanol fraction was incubated with α-glucosidase and then active compounds would form enzyme-inhibitor complexes. The complexes could be separated from inactive components by the interception ability of ultrafiltration membrane under centrifugation. A total of 36 active compounds were screened from C. paliurus leaves and the chemical structures were further characterized by UPLC-QTOF-MS/MS. Furthermore, molecular docking was performed to investigate possible inhibitory mechanisms between active compounds and α-glucosidase. The docking result showed that cyclocarioside I, pterocaryoside B, arjunolic acid, cyclocarioside Z5, cypaliuruside D and cyclocarioside N could be embedded well into the active pocket of α-glucosidase, and had significant affinity interactions with critical amino acid residues by forming hydrogen bonds, hydrophobic interactions and van der Waals, and affinity energies ranged from -9.3 to -6.7 kJ/mol. The results indicated that the developed method is rapid and effective for high throughput screening of potential α-glucosidase inhibitors from complex mixtures. Moreover, C. paliurus exhibited a remarkable inhibitory activity on α-glucosidase, making it a promising candidate for the prevention of DM.

Benzothiazole Amides as TRPC3/6 Inhibitors for Gastric Cancer Treatment.

Transient receptor potential canonical channel 6 (TRPC6) has been implicated in many kinds of malignant tumors, but very few potent TRPC6 antagonists are available. In this study, a benzothiazole amide derivative 1a was discovered as a TRPC6 activator in a cell-based high-throughput screening. A series of benzothiazole amide derivatives were designed and synthesized. The docking analyses indicated that the conformations of the compounds bound to TRPC6 determined the agonistic or antagonistic activity of the compounds against TRPC6, and compound 1s with the tetrahydronaphthalene group in R1 position fit well into the binding pocket of the antagonist-bound conformation of TRPC6. Compound 1s showed an inhibitory potency order of TRPC3 (IC50 3.3 ± 0.13 µM) ≈ C6 (IC50 4.2 ± 0.1 µM) > C7 with good anti-gastric cancer activity in a micromolecular range against AGS and MKN-45, respectively. In addition, 1s inhibited the invasion and migration of MKN-45 cells in vitro.

Built-in electric field for photocatalytic overall water splitting through a TiO2/BiOBr P-N heterojunction.

Photocatalytic overall water splitting to simultaneously obtain abundant hydrogen and oxygen is still the mountain that stands in the way for the practical applications of hydrogen energy, in which composite semiconductor photocatalysts are critical for providing both electrons and holes to promote the following redox reaction. However, the interface between different components forms a deplete layer to hinder the charge transfer to a large extent. In order to enhance the charger transfer from an interface to the surface and promote the spatial separation of electron-hole pairs, a built-in electric field induced by a p-n heterojunction emerges as the best choice. As a touchstone, a p-n heterojunction of TiO2/BiOBr with a strong built-in electric field has been constructed, which presents a wide spectrum response owing to its interleaved band gaps after composition. The built-in electric field greatly enhances the separation and transportation of photogenerated carriers, resulting in fluorescence quenching due to the carrier recombination. The sample also displayed exceptional photoelectron responses: its photocurrent density (43.3 µA cm-2) was over 10 times that of TiO2 (3.5 µA cm-2) or BiOBr (4.2 µA cm-2). In addition, the sample with a molar ratio of 3 : 1 between TiO2 and BiOBr showed the best photocatalytic overall water splitting performance under visible light (λ > 420 nm): the hydrogen and oxygen production rate were 472.7 µmol gcat.-1 h-1 and 95.7 µmol gcat.-1 h-1, respectively, which are the highest values under visible light without other cocatalysts to have been reported in literature for the photocatalyst.

Optimizing the Protein Fluorescence Reporting System for Somatic Embryogenesis Regeneration Screening and Visual Labeling of Functional Genes in Cotton.

Protein fluorescence reporting systems are of crucial importance to in-depth life science research, providing systematic labeling tools for visualization of microscopic biological activities in vivo and revolutionizing basic research. Cotton somatic cell regeneration efficiency is low, causing difficulty in cotton transformation. It is conducive to screening transgenic somatic embryo using the fluorescence reporting system. However, available fluorescence labeling systems in cotton are currently limited. To optimize the fluorescence reporting system of cotton with an expanded range of available fluorescent proteins, we selected 11 fluorescent proteins covering red, green, yellow, and cyan fluorescence colors and expressed them in cotton. Besides mRuby2 and G3GFP, the other nine fluorescent proteins (mCherry, tdTomato, sfGFP, Clover, EYFP, YPet, mVenus, mCerulean, and ECFP) were stably and intensely expressed in transgenic callus and embryo, and inherited in different cotton organs derive from the screened embryo. In addition, transgenic cotton expressing tdTomato appears pink under white light, not only for callus and embryo tissues but also various organs of mature plants, providing a visual marker in the cotton genetic transformation process, accelerating the evaluation of transgenic events. Further, we constructed transgenic cotton expressing mCherry-labeled organelle markers in vivo that cover seven specific subcellular compartments: plasma membrane, endoplasmic reticulum, tonoplast, mitochondrion, plastid, Golgi apparatus, and peroxisome. We also provide a simple and highly efficient strategy to quickly determine the subcellular localization of uncharacterized proteins in cotton cells using organelle markers. Lastly, we built the first cotton stomatal fluorescence reporting system using stomata-specific expression promoters (ProKST1, ProGbSLSP, and ProGC1) to drive Clover expression. The optimized fluorescence labeling system for transgenic somatic embryo screening and functional gene labeling in this study offers the potential to accelerating somatic cell regeneration efficiency and the in vivo monitoring of diverse cellular processes in cotton.

Discovery of novel potential plant growth regulators from Corydalis mucronifera.

Three pairs of enantiomers mucroniferals A-C (1-3), with a novel skeleton of 1,4-epoxynaphthalene-2,3-dicarboxylic acid first reported from nature source, were isolated from Corydalis mucronifera. Their structures were elucidated based on extensive spectroscopic data analysis of MS, 1D and 2D NMR, and their absolute configurations were confirmed by single-crystal X-ray diffraction analysis and comparison of the experimental and calculated ECD data. Mucroniferals A-C showed broad-spectrum inhibitory activities on seedling growth of all plants tested (Lepidium apetalum, Raphanus sativus, Lactuca sativa, and Arabidopsis thaliana) with a dose-dependent relationship. Additionally, mucroniferals A and B exhibited significant inhibitory effects on germination of most seeds at concentration of 80 µg/mL, and the inhibition was reversible.

Programmed Ultrafast Scan Welding of Cu Nanowire Networks with a Pulsed Ultraviolet Laser Beam for Transparent Conductive Electrodes and Flexible Circuits.

Metal nanowires (NWs) have shown superior advances for the next-generation transparent conducting (TC) materials. Most concerns were focused on uniform conductive films; however, fabrication of a programmed circuit is still lacking. Here, we demonstrate a programmable ultrafast welding method by pulsed laser beam scanning under ambient conditions to achieve a Cu NW pattern-free TC circuit as well as various size films. High-aspect ratio Cu NWs (> 3000) are synthesized through an oleylamine-mediated solution system. Pulsed ultraviolet laser irradiation together with a programmed moving station is set up for the welding of Cu NW networks. Finite element simulations reveal that the transient heating by efficient absorption of UV light (∼ 250 nm) could remove the organic residues on the surface and realize local welding of interlaced NW junctions. With only 10 ms pulsed irradiation, high optoelectronic performance (33 ohm/sq. at 87% transmittance at 550 nm) and excellent stability of the Cu NW TC film have been achieved. The line-by-line and selected route scanning modes could rapidly make large area TC films and directly write flexible circuits. Moreover, completely transparent micron-size UV and blue LED chips are fabricated and successfully lit with bright emission. This method opens up a future way of circuit and device fabrication by direct one-step laser writing.

Cu Nanowires Passivated with Hexagonal Boron Nitride: An Ultrastable, Selectively Transparent Conductor.

The copper nanowire (Cu NW) network is considered a promising alternative to indium tin oxide as transparent conductors for advanced optoelectronic devices. However, the fast degradation of copper in ambient conditions largely overshadows its practical applications. Here we demonstrate a facile method for epitaxial growth of hexagonal boron nitride (h-BN) of a few atomic layers on interlaced Cu NWs by low-pressure chemical vapor deposition, which exhibit excellent thermal and chemical stability under high temperature (900 °C in vacuum), high humidity (95% RH), and strong base/oxidizer solution (NaOH/H2O2). Meanwhile, their optical and electrical performances remain similar to those of the original Cu NWs (e.g., high optical transmittance (∼93%) and high conductivity (60.9 Ω/□)). A smart privacy glass is successfully fabricated based on a Cu@h-BN NW network and liquid crytal, which could rapidly control the visibility from transparent to opaque (0.26 s) and, at the same time, strongly block the mid-infrared light for energy saving by screening radiative heat. This precise engineering of epitaxial Cu@h-BN core-shell nanostructure offers broad applications in high-performance electronic and optoelectronic devices.

Identification of NHXs in Gossypium species and the positive role of GhNHX1 in salt tolerance.

BACKGROUND: Plant Na+/H+ antiporters (NHXs) are membrane-localized proteins that maintain cellular Na+/K+ and pH homeostasis. Considerable evidence highlighted the critical roles of NHX family in plant development and salt response; however, NHXs in cotton are rarely studied. RESULTS: The comprehensive and systematic comparative study of NHXs in three Gossypium species was performed. We identified 12, 12, and 23 putative NHX proteins from G. arboreum, G. raimondii, and G. hirsutum, respectively. Phylogenetic study revealed that repeated polyploidization of Gossypium spp. contributed to the expansion of NHX family. Gene structure analysis showed that cotton NHXs contain many introns, which will lead to alternative splicing and help plants to adapt to high salt concentrations in soil. The expression changes of NHXs indicate the possible differences in the roles of distinct NHXs in salt response. GhNHX1 was proved to be located in the vacuolar system and intensively induced by salt stress in cotton. Silencing of GhNHX1 resulted in enhanced sensitivity of cotton seedlings to high salt concentrations, which suggests that GhNHX1 positively regulates cotton tolerance to salt stress. CONCLUSION: We characterized the gene structure, phylogenetic relationship, chromosomal location, and expression pattern of NHX genes from G. arboreum, G. raimondii, and G. hirsutum. Our findings indicated that the cotton NHX genes are regulated meticulously and differently at the transcription level with possible alternative splicing. The tolerance of plants to salt stress may rely on the expression level of a particular NHX, rather than the number of NHXs in the genome. This study could provide significant insights into the function of plant NHXs, as well as propose promising candidate genes for breeding salt-resistant cotton cultivars.

Enhanced Emission of Deep Ultraviolet Light-Emitting Diodes through Using Work Function Tunable Cu Nanowires as the Top Transparent Electrode.

Deep ultraviolet light-emitting diodes (DUV LEDs) (<280 nm) have been important light sources for broad applications in, e.g., sterilization, purification, and high-density storage. However, the lack of excellent transparent electrodes in the DUV region remains a challenging issue. Here, we demonstrate an architectural engineering scheme to flexibly tune the work function of Cu@shell nanowires (NWs) as top transparent electrodes in DUV LEDs. By fast encapsulation of shell metals on Cu NWs and a shift of electron binding energy, the electronic work function could be widely tailored down to 4.37 eV and up to 5.73 eV. It is revealed that the high work function of Cu@Ni and Cu@Pt NWs could overcome the interfacial barrier to p-AlGaN and achieve direct ohmic contact with high transparency (91%) in 200-400 nm. Completely transparent DUV LED chips are fabricated and successfully lighted with sharp top emission (wall-plug efficiency reaches 3%) under a turn-on voltage of 6.4 V. This architectural strategy is of importance in providing highly transparent ohmic electrodes for optoelectronic devices in broad wavelength regions.

Comparative acetylome analysis of wild-type and fuzzless-lintless mutant ovules of upland cotton (Gossypium hirsutum Cv. Xu142) unveils differential protein acetylation may regulate fiber development.

Protein acetylation (KAC) is a significant post-translational modification, which plays an essential role in the regulation of growth and development. Unfortunately, related studies are inadequately available in angiosperms, and to date, there is no report providing insight on the role of protein acetylation in cotton fiber development. Therefore, we first compared the lysine-acetylation proteome (acetylome) of upland cotton ovules in the early fiber development stages by using wild-type as well as its fuzzless-lintless mutant to identify the role of KAC in the fiber development. A total of 1696 proteins with 2754 acetylation sites identified with the different levels of acetylation belonging to separate subcellular compartments suggesting a large number of proteins differentially acetylated in two cotton cultivars. About 80% of the sites were predicted to localize in the cytoplasm, chloroplast, and mitochondria. Seventeen significantly enriched acetylation motifs were identified. Serine and threonine and cysteine located downstream and upstream to KAC sites. KEGG pathway enrichment analysis indicated oxidative phosphorylation, fatty acid, ribosome and protein, and folate biosynthesis pathways enriched significantly. To our knowledge, this is the first report of comparative acetylome analysis to compare the wild-type as well as its fuzzless-lintless mutant acetylome data to identify the differentially acetylated proteins, which may play a significant role in cotton fiber development.