COP1 and ELF3 control circadian function and photoperiodic flowering by regulating GI stability.

Seasonal changes in day length are perceived by plant photoreceptors and transmitted to the circadian clock to modulate developmental responses such as flowering time. Blue-light-sensing cryptochromes, the E3 ubiquitin-ligase COP1, and clock-associated proteins ELF3 and GI regulate this process, although the regulatory link between them is unclear. Here we present data showing that COP1 acts with ELF3 to mediate day length signaling from CRY2 to GI within the photoperiod flowering pathway. We found that COP1 and ELF3 interact in vivo and show that ELF3 allows COP1 to interact with GI in vivo, leading to GI degradation in planta. Accordingly, mutation of COP1 or ELF3 disturbs the pattern of GI cyclic accumulation. We propose a model in which ELF3 acts as a substrate adaptor, enabling COP1 to modulate light input signal to the circadian clock through targeted destabilization of GI.

Molecular evolution and functional divergence of X-intrinsic protein genes in plants.

X-intrinsic proteins (XIPs) are a novel class of major intrinsic proteins found in diverse organisms. Recently, XIP genes have been reported to be involved in the transport of a wide range of hydrophobic solutes; however, the evolutionary forces driving their structural and functional divergence in plants are poorly understood. In the present study, comprehensive bioinformatics analyses were performed to gain insight into the molecular and evolutionary mechanisms driving this structural and functional diversification. Phylogenetic analyses have revealed the major lineage-specific expansions of XIP genes in plants. Within the eudicots, XIP genes have diverged into Asterid and Rosid-specific phylogenetic lineages and have also undergone several independent duplications during the course of evolution. Investigation of functional divergence at the protein level showed evidence for shifting evolutionary rate and/or altered constraints on the physiochemical properties of specific amino acid sites following gene duplication. Selection pressure analyses suggest that purifying selection is the predominant evolutionary force acting on the XIP gene subfamily, along with episodic positive selection. However, only a few amino acid sites were found to be subjected to such episodic positive selection. Furthermore, protein functional divergence analysis has identified critical amino acid residues, which must be validated by future experimental studies, that could provide new insights into the role of XIPs in transport of a wide range solutes of physiological importance.

A systematic exploration of high-temperature stress-responsive genes in potato using large-scale yeast functional screening.

Potato (S. tuberosum) is a highly heat-sensitive crop; a slight rise from optimal temperature can lead to drastic decline in tuber yield. Despite several advancements made in breeding for thermo-tolerant potato, molecular mechanisms governing thermo-tolerance is poorly understood. The first step towards understanding the thermo-tolerance mechanism is to identify the key genes involved in it. Here we used a yeast-based functional screening method to identify, characterize and classify potato genes with potentials to impart heat tolerance. We constructed two cDNA expression libraries from heat-stressed potato plants (35 °C) after 2 and 48 h of treatment. 95 potential candidate genes were identified based on enhanced ability of yeast cells over-expressing heterologous potato cDNA sequences to tolerate heat stress. Cross-resistance analysis of these heat-tolerant yeast clones to other abiotic stresses indicated that 20 genes were responsive to drought, 14 to salt and 11 to heat/drought/salt stresses. Comparison of 95 genes with reported whole potato transcriptome data showed that majority of them have varying expression patterns under heat, drought and salt stresses. The expression pattern was validated by analyzing the expression of 22 randomly selected genes under various stresses using qPCR. Gene ontology (GO) enrichment analysis of these 95 genes indicated that most of them are involved in various cellular metabolism, signal transduction, response to stress and protein folding, suggesting possible role of these genes in heat tolerance of potato. Genes identified from this study can be potential candidates for engineering heat tolerance as well as broad-spectrum abiotic stress tolerance of potato.

Effects of Thermal Treatment on DC Voltage-Driven Color Conversion in Organic Light-Emitting Diode.

A DC voltage-dependent color-tunable organic light-emitting diode (CTOLED) was proposed for lighting applications. The CTOLED consists of six consecutive organic layers: the hole injection layer, the hole transport layer (HTL), two emission layers (EMLs), a hole blocking layer (HBL), and an electron transport layer (ETL). Only one metal-free phthalocyanine (H2Pc) layer with a thickness of 5 nm was employed as the EML in the CTOLED on a green organic light-emitting diode (OLED) structure using tris (8-hydroxyquinoline) aluminum (III) (Alq3). The current density-voltage-luminance characteristics of the CTOLEDs before and after thermal treatment were characterized and analyzed. Several Gaussian peaks were also extracted by multipeak fitting analysis of the electroluminescent spectra. In the CTOLED before thermal treatment, green emission was dominant in the entire voltage range from low to high voltages, and blue and infrared were emitted simultaneously and at relatively low intensities at low and high voltages, respectively. In the CTOLED after thermal treatment, the dominant color conversion from blue to green was observed as the applied voltage increased, and the infrared emission was relatively low over the entire voltage range. By simulating the CTOLED with and without traps at the H2Pc interface using a technology computer-aided design simulator, we observed the following: 1. After thermal treatment, the CTOLED emitted blue light by exciton generation at the H2Pc-HBL interface because of the small electron transport through the H2Pc thin film due to the dramatic reduction of traps in the low-voltage regime. 2. In the high-voltage regime, electrons reaching the HBL were transferred to Alq3 by resonant tunneling in two quantum wells; thus, green light was emitted by exciton generation at the HTL-Alq3 interface.

Thin film encapsulation for quantum dot light-emitting diodes using a-SiN x :H/SiO x N y /hybrid SiO x barriers.

A facile thin film encapsulation (TFE) method having a triple-layered structure of a-SiN x :H/SiO x N y /hybrid SiO x (ASH) on QD-LEDs was performed utilizing both reproducible plasma-enhanced chemical vapor deposition (PECVD) and simple dip-coating processes without adopting atomic layer deposition (ALD). The ASH films fabricated on a polyethylene terephthalate (PET) substrate show a high average transmittance of 88.80% in the spectral range of 400-700 nm and a water vapor transmission rate (WVTR) value of 7.3 × 10-4 g per m2 per day. The measured time to reach 50% of the initial luminance (T50) at initial luminance values of 500, 1000, and 2000 cd m-2 was 711.6, 287.7, and 78.6 h, respectively, and the extrapolated T50 at 100 cd m-2 is estimated to be approximately 9804 h, which is comparable to that of the 12 112 h for glass lid-encapsulated QD-LEDs. This result demonstrates that TFE with the ASH films has the potential to overcome the conventional drawbacks of glass lid encapsulation.

Genotyping-by-Sequencing-Based Genome-Wide Association Studies of Fusarium Wilt Resistance in Radishes (Raphanus sativus L.).

Fusarium wilt (FW) is a fungal disease that causes severe yield losses in radish production. The most effective method to control the FW is the development and use of resistant varieties in cultivation. The identification of marker loci linked to FW resistance are expected to facilitate the breeding of disease-resistant radishes. In the present study, we applied an integrated framework of genome-wide association studies (GWAS) using genotyping-by-sequencing (GBS) to identify FW resistance loci among a panel of 225 radish accessions, including 58 elite breeding lines. Phenotyping was conducted by manual inoculation of seedlings with the FW pathogen, and scoring for the disease index was conducted three weeks after inoculation during two constitutive years. The GWAS analysis identified 44 single nucleotide polymorphisms (SNPs) and twenty putative candidate genes that were significantly associated with FW resistance. In addition, a total of four QTLs were identified from F2 population derived from a FW resistant line and a susceptible line, one of which was co-located with the SNPs on chromosome 7, detected in GWAS study. These markers will be valuable for molecular breeding programs and marker-assisted selection to develop FW resistant varieties of R. sativus.

Hybrid Thin-Film Encapsulation for All-Solid-State Thin-Film Batteries.

All-solid-state thin-film batteries have been actively investigated as a power source for various microdevices. However, insufficient research has been conducted on thin-film encapsulation, which is an essential element of these batteries as solid electrolytes and Li anodes are vulnerable to moisture in the atmosphere. In this study, a hybrid thin-film encapsulation structure of hybrid SiOy/SiNxOy/a-SiNx:H/Parylene is suggested and investigated. The water-vapor transmission rate of hybrid thin-film encapsulation is estimated to be 4.9 × 10-3 g m-2·day-1, a value that is applicable to batteries as well as flexible solar cells, thin-film transistor liquid-crystal display, and E-papers. As a result of hybrid thin-film encapsulation, it is confirmed that the all-solid-state thin-film batteries are stable even after 100 charge/discharge cycles in the air atmosphere for 30 days and present a Coulombic efficiency of 99.8% even after 100 cycles in the air atmosphere. These results demonstrate that the thin-film encapsulation structure of hybrid SiOy/SiNxOy/a-SiNx:H/Parylene can be employed in thin-film batteries while retaining long-term stability.

Ultralow Water Permeation Barrier Films of Triad a-SiNx:H/n-SiOxNy/h-SiOx Structure for Organic Light-Emitting Diodes.

Organic electronic devices such as organic light-emitting diodes (OLEDs), quantum dot LEDs, and organic photovoltaics are promising technologies for future electronics. However, achieving long-term stability of organic-based optoelectronic devices has been regarded as a crucial problem to be solved. In this work, a simple and reproducible fabrication method for ultralow water permeation barrier films having a triple-layered (triad) hydrogenated silicon nitride (a-SiNx:H)/nanosilicon oxynitride (n-SiOxNy)/hybrid silicon oxide (h-SiOx) multistructure is presented. Two triad (a-SiNx:H/n-SiOxNy/h-SiOx)n=2 multistructure barrier films are deposited on both sides of a poly(ethylene terephthalate) substrate using a combination of low-pressure plasma-enhanced chemical vapor deposition and dip coating. The deposited films show a high average transmittance (400-700 nm) of 84% and an ultralow water vapor transmission rate of 2 × 10-6 g/m2/day. In the electroluminescence characteristics of OLEDs encapsulated with two triad barrier films, the operational lifetime (T50) of OLEDs is 1584 h, which is almost similar to that (1416 h) of OLEDs encapsulated with a glass lid.

The Hypernodulating nts mutation induces jasmonate synthetic pathway in soybean leaves.

Symbiotic nitrogen fixation with nitrogen-fixing bacteria in the root nodules is a distinctly beneficial metabolic process in legume plants. Legumes control the nodule number and nodulation zone through a systemic negative regulatory system between shoot and root. Mutation in the soybean NTS gene encoding GmNARK, a CLAVATA1-like serine/threonine receptor-like kinase, causes excessive nodule development called hypernodulation. To examine the effect of nts mutation on the gene expression profile in the leaves, suppression subtractive hybridization was performed with the trifoliate leaves of nts mutant 'SS2-2' and the wild-type (WT) parent Sinpaldalkong2, and 75 EST clones that were highly expressed in the leaves of the SS2-2 mutant were identified. Interestingly, the expression of jasmonate (JA)-responsive genes such as vspA, vspB, and Lox2 were upregulated, whereas that of a salicylate-responsive gene PR1a was suppressed in the SS2-2 mutant. In addition, the level of JA was about two-fold higher in the leaves of the SS2-2 mutant than in those of the WT under natural growth conditions. Moreover, the JA-responsive gene expression persists in the leaves of SS2-2 mutant without rhizobia infection in the roots. Taken together, our results suggest that the nts mutation increases JA synthesis in mature leaves and consequently leads to constitutive expression of JA-responsive genes which is irrelevant to hypernodulation in the root.

Genome sequence of pacific abalone (Haliotis discus hannai): the first draft genome in family Haliotidae.

Background: Abalones are large marine snails in the family Haliotidae and the genus Haliotis belonging to the class Gastropoda of the phylum Mollusca. The family Haliotidae contains only one genus, Haliotis, and this single genus is known to contain several species of abalone. With 18 additional subspecies, the most comprehensive treatment of Haliotidae considers 56 species valid [ 1 ]. Abalone is an economically important fishery and aquaculture animal that is considered a highly prized seafood delicacy. The total global supply of abalone has increased 5-fold since the 1970s and farm production increased explosively from 50 mt to 103 464 mt in the past 40 years. Additionally, researchers have recently focused on abalone given their reported tumor suppression effect. However, despite the valuable features of this marine animal, no genomic information is available for the Haliotidae family and related research is still limited. To construct the H . discus hannai genome, a total of 580-G base pairs using Illumina and Pacbio platforms were generated with 322-fold coverage based on the 1.8-Gb estimated genome size of H . discus hannai using flow cytometry. The final genome assembly consisted of 1.86 Gb with 35 450 scaffolds (>2 kb). GC content level was 40.51%, and the N50 length of assembled scaffolds was 211 kb. We identified 29 449 genes using Evidence Modeler based on the gene information from ab initio prediction, protein homology with known genes, and transcriptome evidence of RNA-seq. Here we present the first Haliotidae genome, H . discus hannai , with sequencing data, assembly, and gene annotation information. This will be helpful for resolving the lack of genomic information in the Haliotidae family as well as providing more opportunities for understanding gastropod evolution.

Differential induction of meristematic stem cells of Catharanthus roseus and their characterization.

Plant cell culture technology has been introduced for the mass production of the many useful components. A variety of plant-derived compounds is being used in various fields, such as pharmaceuticals, foods, and cosmetics. Plant cell cultures are believed to be derived from the dedifferentiation process. In the present study, an undifferentiated cambial meristematic cell (CMCs) of Catharanthus is isolated using histological and genetic methods, and compared with dedifferentiation-derived callus (DDCs) cultures. Furthermore, differential culture conditions for both DDCs- and CMCs-derived cell lines were established. A suitable media for the increased accumulation of terpenoid indole alkaloids (TIAs) was also standardized. Compared with DDCs, CMCs showed marked accumulation of TIAs in cell lines grown on media with 1.5 mg·mL(-1) of NAA and 0.5 mg·mL(-1) of kinetin. CMCs-derived cultures of Catharanthus, as a source of key anticancer drugs (viblastine and vincristine), would overcome the obstacles usually associated with the production of natural metabolites through the use of DDCs. Cell culture systems that are derived from CMCs may also provide a cost-effective and eco-friendly basis for the sustainable production of a number of important plant natural products.

Genome-wide analysis and expression profiling of the Solanum tuberosum aquaporins.

Aquaporins belongs to the major intrinsic proteins involved in the transcellular membrane transport of water and other small solutes. A comprehensive genome-wide search for the homologues of Solanum tuberosum major intrinsic protein (MIP) revealed 41 full-length potato aquaporin genes. All potato aquaporins are grouped into five subfamilies; plasma membrane intrinsic proteins (PIPs), tonoplast intrinsic proteins (TIPs), NOD26-like intrinsic proteins (NIPs), small basic intrinsic proteins (SIPs) and x-intrinsic proteins (XIPs). Functional predictions based on the aromatic/arginine (ar/R) selectivity filters and Froger's positions showed a remarkable difference in substrate transport specificity among subfamilies. The expression pattern of potato aquaporins, examined by qPCR analysis, showed distinct expression profiles in various organs and tuber developmental stages. Furthermore, qPCR analysis of potato plantlets, subjected to various abiotic stresses revealed the marked effect of stresses on expression levels of aquaporins. Taken together, the expression profiles of aquaporins imply that aquaporins play important roles in plant growth and development, in addition to maintaining water homeostasis in response to environmental stresses.

Evaluation of abiotic stress tolerance in transgenic potato plants with reduced expression of PSII manganese stabilizing protein.

Manganese stabilizing protein (MSP) is an important component of the Photosystem II (PSII) oxygen evolving complex. In our previous work, transgenic potato plants with reduced expression of MSP (MSP-As) were developed and their physiological and biochemical responses were studied. In this report, we address the response of MSP-As plants toward salinity, heavy metal and osmotic stresses. MSP-As plants treated with NaCl, ZnCl(2) or mannitol solution showed significant level of tolerance under all the stress conditions. Specific enzyme activities of major ROS-scavenging enzymes were found significantly higher in MSP-As plants than the control plants. MSP-As plants accumulated increased levels of proline and low molecular weight metabolites such as ascorbate and α-tocopherol, which indicated that these plants were much more resistant to stress compared to the corresponding control plants. The primary photochemical efficiencies and the OJIP kinetics analyses further confirmed that MSP-As plants were in better optimal health under stress compared to the control plants. Although the exact reason behind the increased stress tolerance in stressed MSP-As plants is unclear, our results strongly indicate the role of MSP of unknown function in abiotic stress tolerance.

Rapid identification of potential drought tolerance genes from Solanum tuberosum by using a yeast functional screening method.

Identification of major stress tolerance genes of a crop plant is important for the rapid development of its stress-tolerant cultivar. Here, we used a yeast functional screen method to identify potential drought-tolerance genes from a potato plant. A cDNA expression library was constructed from hyperosmotic stressed potato plants. The yeast transformants expressing different cDNAs were selected for their ability to survive in hyperosmotic stress conditions. The relative tolerances of the selected yeast transformants to multiple abiotic stresses were also studied. Specific potato cDNAs expressed in the tolerant yeast transformants were identified. Sixty-nine genes were found capable of enhancing hyperosmotic stress tolerance of yeast. Based on the relative tolerance data generated, 12 genes were selected, which could be most effective in imparting higher drought tolerance to potato with better survival in salt and high-temperature stresses. Orthologues of few genes identified here are previously known to increase osmotic stress tolerance of yeast and plants; however, specific studies are needed to confirm their role in the osmotic stress tolerance of potato.

Engineering glucosinolates in plants: current knowledge and potential uses.

Glucosinolates (GSL) and their derivatives are well known for the characteristic roles they play in plant defense as signaling molecules and as bioactive compounds for human health. More than 130 GSLs have been reported so far, and most of them belong to the Brassicaceae family. Several enzymes and transcription factors involved in the GSL biosynthesis have been studied in the model plant, Arabidopsis, and in a few other Brassica crop species. Recent studies in GSL research have defined the regulation, distribution, and degradation of GSL biosynthetic pathways; however, the underlying mechanism behind transportation of GSLs in plants is still largely unknown. This review highlights the recent advances in the metabolic engineering of GSLs in plants and discusses their potential applications.

Dynamic proteomic profile of potato tuber during its in vitro development.

Potato tuberization is a complicated biochemical process, which is dependent on external environmental factors. Tuber development in potato consists of a series of biochemical and morphological processes at the stolon tip. Signal transduction proteins are involved in the source-sink transition during potato tuberization. In the present study, we examined protein profiles under in vitro tuber-inducing conditions using a shotgun proteomic approach involving denaturing gel electrophoresis and liquid chromatography-mass spectrometry. A total of 251 proteins were identified and classified into 9 groups according to distinctive expression patterns during the tuberization stage. Stolon stage-specific proteins were primarily involved in the photosynthetic machinery. Proteins specific to the initial tuber stage included patatin. Proteins specific to the developing tuber stage included 6-fructokinase, phytoalexin-deficient 4-1, metallothionein II-like protein, and malate dehydrogenase. Novel stage-specific proteins identified during in vitro tuberization were ferredoxin-NADP reductase, 34 kDa porin, aquaporin, calmodulin, ripening-regulated protein, and starch synthase. Superoxide dismutase, dehydroascorbate reductase, and catalase I were most abundantly expressed in the stolon; however, the enzyme activities of these proteins were most activated at the initial tuber. The present shotgun proteomic study provides insights into the proteins that show altered expression during in vitro potato tuberization.

Highly aligned ultrahigh density arrays of conducting polymer nanorods using block copolymer templates.

Ultrahigh density arrays of conducting polypyrrole (PPy) nanorods are fabricated directly on the indium-tin oxide coated glass by an electropolymerization within a porous diblock copolymer template. The nanorods are shown to have conductivity much higher than thin PPy films, due to the high degree of chain orientation, even though the separation distance for two neighboring PPy main chains is as small as 0.37 nm. The ultrahigh density arrays of conducting polymer nanorods have potential applications as sensor materials, nanoactuators, and organic photovoltaic devices.

The senescence-induced staygreen protein regulates chlorophyll degradation.

Loss of green color in leaves results from chlorophyll (Chl) degradation in chloroplasts, but little is known about how Chl catabolism is regulated throughout leaf development. Using the staygreen (sgr) mutant in rice (Oryza sativa), which maintains greenness during leaf senescence, we identified Sgr, a senescence-associated gene encoding a novel chloroplast protein. Transgenic rice overexpressing Sgr produces yellowish-brown leaves, and Arabidopsis thaliana pheophorbide a oxygenase-impaired mutants exhibiting a stay-green phenotype during dark-induced senescence have reduced expression of Sgr homologs, indicating that Sgr regulates Chl degradation at the transcriptional level. We show that the leaf stay-greenness of the sgr mutant is associated with a failure in the destabilization of the light-harvesting chlorophyll binding protein (LHCP) complexes of the thylakoid membranes, which is a prerequisite event for the degradation of Chls and LHCPs during senescence. Transient overexpression of Sgr in Nicotiana benthamiana and an in vivo pull-down assay show that Sgr interacts with LHCPII, indicating that the Sgr-LHCPII complexes are formed in the thylakoid membranes. Thus, we propose that in senescing leaves, Sgr regulates Chl degradation by inducing LHCPII disassembly through direct interaction, leading to the degradation of Chls and Chl-free LHCPII by catabolic enzymes and proteases, respectively.

Reverse transcriptase domain sequences from Mungbean (Vigna radiata) LTR retrotransposons: sequence characterization and phylogenetic analysis.

The conserved domains of reverse transcriptase (RT) genes of Ty1-copia and Ty3-gypsy groups of long terminal repeat (LTR) retrotransposons were amplified from mungbean (Vigna radiata) genome using degenerate primers, cloned and sequenced. Among these 34% and 65% of respective clones of copia and gypsy RT sequences possessed stop codons or frame-shifts or both. The RT sequences corresponding to both the groups exhibit significant levels of heterogeneity. Presence of mungbean copia and gypsy RT sequences in other papilionoid legumes of the same (Phaseoleae) and different lineages (Loteae, Trifoleae, Cicereae) indicates existence of these elements prior to the radiation of papilionoid legumes and also supports the recent interpretations of close relationship between Phaseoleae and Loteae tribes of Papilionoideae subfamily. On the other hand significant homologies of some mungbean copia as well as gypsy RT sequences with those of unrelated plant species suggest their origin from different plant lineages and also that heterogeneous population of related elements were already existed throughout (even before the divergence of monocot and dicot) the evolution of these genera from their common ancestor.