Novel genomes and genome constitutions identified by GISH and 5S rDNA and knotted1 genomic sequences in the genus Setaria

Background: The Setaria genus is increasingly of interest to researchers, as its two species, S. viridis and S. italica, are being developed as models for understanding C4 photosynthesis and plant functional genomics. The genome constitution of Setaria species has been studied in the diploid species S. viridis, S. adhaerans and S. grisebachii, where three genomes A, B and C were identified respectively. Two allotetraploid species, S. verticillata and S. faberi, were found to have AABB genomes, and one autotetraploid species, S. queenslandica, with an AAAA genome, has also been identified. The genomes and genome constitutions of most other species remain unknown, even though it was thought there are approximately 125 species in the genus distributed world-wide.Results: GISH was performed to detect the genome constitutions of Eurasia species of S. glauca, S. plicata, and S. arenaria, with the known A, B and C genomes as probes. No or very poor hybridization signal was detected indicating that their genomes are different from those already described. GISH was also performed reciprocally between S. glauca, S. plicata, and S. arenaria genomes, but no hybridization signals between each other were found. The two sets of chromosomes of S. lachnea both hybridized strong signals with only the known C genome of S. grisebachii. Chromosomes of Qing 9, an accession formerly considered as S. viridis, hybridized strong signal only to B genome of S. adherans. Phylogenetic trees constructed with 5S rDNA and knotted1 markers, clearly classify the samples in this study into six clusters, matching the GISH results, and suggesting that the F genome of S. arenaria is basal in the genus.Conclusions: Three novel genomes in the Setaria genus were identified and designated as genome D (S. glauca), E (S. plicata) and F (S. arenaria) respectively. The genome constitution of tetraploid S. lachnea is putatively CCC’C’. Qing 9 is a B genome species indigenous to China and is hypothesized to be a newly identified species. The difference in genome constitution and origin of S. verticillata and S. faberi is also discussed. The new genomes and the genome constitutions of Setaria species identified in this report provide useful information for Setaria germplasm management, foxtail millet breeding, grass evolution and the development of S. viridis and S. italica as a new model for functional genomics.Peer reviewedBotan

Effect of Interfacial Bonds on the Morphology of InAs QDs Grown on GaAs (311) B and (100) Substrates

The morphology and transition thickness (tc) for InAs quantum dots (QDs) grown on GaAs (311) B and (100) substrates were investigated. The morphology varies with the composition of buffer layer and substrate orientation. Andtcdecreased when the thin InGaAs was used as a buffer layer instead of the GaAs layer on (311) B substrates. For InAs/(In)GaAs QDs grown on high miller index surfaces, both the morphology andtccan be influenced by the interfacial bonds configuration. This indicates that buffer layer design with appropriate interfacial bonds provides an approach to adjust the morphologies of QDs grown on high miller surfaces

Density Functional Simulation of Adsorption Behavior within the Dicalcium Silicate-Accelerated Carbonation System

In this study, the adsorption behavior of various molecules, including H2O, CO2, and H2CO3, on the C2S surface in the carbonation system was systematically compared to elucidate the microscopic mechanism in early accelerated carbonation using density functional theory and ab initio molecular dynamics. The electronic structures on β-C2S and γ-C2S surfaces differ, in that the valence band maximum is contributed by the O p orbital and Ca s orbital, respectively. This difference results in different proton–surface interactions. The protons hydroxylated the [SiO4]4– tetrahedra on the β-C2S surface. On the γ-C2S surface, the protons enter the interior surface to form a three-coordination configuration with Ca atoms in addition to bonding with the [SiO4]4– tetrahedra. The adsorption energy for the dissociative adsorption of H2CO3 on both β-C2S and γ-C2S surfaces is significantly higher than that of H2O, and the dissociative adsorption configurations are also more stable. CO2 only has a strong adsorption tendency on the γ-C2S surface, where it acquires electrons from the surface Ca atoms to become activated. In the molecular adsorption phase, γ-C2S interacts more strongly with CO2, H2CO3, and its dissociation products

Analysis of Fault and Protection Strategy of a Converter Station in MMC-HVDC System

With the development of power energy technology, flexible high voltage direct current (HVDC) systems with high control degree of freedom flexibility, power supply to passive systems, small footprint, and other advantages stand out in the field of long-distance large-capacity transmission engineering. HVDC transmission technology based on a modular multilevel converter has been widely used in power grids due to its advantages such as large transmission capacity, less harmonic content, low switching loss, and wide application field. In the modular multilevel converter (MMC)-based HVDC system, the protection strategy of converter station internal faults is directly related to the reliability and security of the power transmission system. Starting from the MMC topological structure, this paper establishes the MMC mathematical model in a synchronous rotation coordinate system by combining the working state of sub-modules and the relationship between each variable of the upper and lower bridge arms of each phase of the MMC. It provides a theoretical basis for the design of the MMC-HVDC control system. The causes of the AC system faults and the internal faults of the converter station in the MMC-HVDC system are analyzed, and the sub-module faults and bridge arm reactor faults in the converter station are studied. The sub-module redundancy protection and bridge arm overcurrent protection strategies are designed for the faults, and the correctness of the scheme is verified by Matlab/Simulink

Analysis of Fault and Protection Strategy of a Converter Station in MMC-HVDC System

With the development of power energy technology, flexible high voltage direct current (HVDC) systems with high control degree of freedom flexibility, power supply to passive systems, small footprint, and other advantages stand out in the field of long-distance large-capacity transmission engineering. HVDC transmission technology based on a modular multilevel converter has been widely used in power grids due to its advantages such as large transmission capacity, less harmonic content, low switching loss, and wide application field. In the modular multilevel converter (MMC)-based HVDC system, the protection strategy of converter station internal faults is directly related to the reliability and security of the power transmission system. Starting from the MMC topological structure, this paper establishes the MMC mathematical model in a synchronous rotation coordinate system by combining the working state of sub-modules and the relationship between each variable of the upper and lower bridge arms of each phase of the MMC. It provides a theoretical basis for the design of the MMC-HVDC control system. The causes of the AC system faults and the internal faults of the converter station in the MMC-HVDC system are analyzed, and the sub-module faults and bridge arm reactor faults in the converter station are studied. The sub-module redundancy protection and bridge arm overcurrent protection strategies are designed for the faults, and the correctness of the scheme is verified by Matlab/Simulink

Silicon nanowire arrays coated with electroless Ag for increased surface-enhanced Raman scattering

The ordered Ag nanorod (AgNR) arrays are fabricated through a simple electroless deposition technique using the isolated Si nanowire (SiNW) arrays as the Ag-grown scaffold. The AgNR arrays have the single-crystallized structure and the plasmonic crystal feature. It is found that the formation of the AgNR arrays is strongly dependent on the filling ratio of SiNWs. A mechanism is proposed based on the selective nucleation and the synergistic growth of Ag nanoparticles on the top of the SiNWs. Moreover, the special AgNR arrays grown on the substrate of SiNWs exhibit a detection sensitivity of 10−15M for rhodamine 6G molecules, which have the potential application to the highly sensitive surface-enhanced Raman scattering sensors

Highly Transparent and Efficient Counter Electrode Using SiO₂/PEDOT–PSS Composite for Bifacial Dye-Sensitized Solar Cells

A highly transparent and efficient counter electrode was facilely fabricated using SiO₂/poly­(3,4-ethylenedioxythiophene)-poly­(styrenesulfonate) (PEDOT–PSS) inorganic/organic composite and used in bifacial dye-sensitized solar cells (DSCs). The optical properties of SiO₂/PEDOT–PSS electrode can be tailored by the blending amount of SiO₂ and film thickness, and the incorporation of SiO₂ in PEDOT–PSS provides better transmission in the long wavelength range. Meanwhile, the SiO₂/PEDOT–PSS counter electrode shows a better electrochemical catalytic activity than PEDOT–PSS electrode for triiodide reduction, and the role of SiO₂ in the catalytic process is investigated. The bifacial DSC with SiO₂/PEDOT–PSS counter electrode achieves a high power conversion efficiency (PCE) of 4.61% under rear-side irradiation, which is about 83% of that obtained under front-side irradiation. Furthermore, the PCE of bifacial DSC can be significantly increased by adding a reflector to achieve bifacial irradiation, which is 39% higher than that under conventional front-side irradiation

FAR-RED ELONGATED HYPOCOTYL3 activates SEPALLATA2 but inhibits CLAVATA3 to regulate meristem determinacy and maintenance in Arabidopsis

Plant meristems are responsible for the generation of all plant tissues and organs. Here we show that the transcription factor (TF) FAR-RED ELONGATED HYPOCOTYL3 (FHY3) plays an important role in both floral meristem (FM) determinacy and shoot apical meristem maintenance in Arabidopsis, in addition to its well-known multifaceted roles in plant growth and development during the vegetative stage. Through genetic analyses, we show that WUSCHEL (WUS) and CLAVATA3 (CLV3), two central players in the establishment and maintenance of meristems, are epistatic to FHY3 Using genome-wide ChIP-seq and RNA-seq data, we identify hundreds of FHY3 target genes in flowers and find that FHY3 mainly acts as a transcriptional repressor in flower development, in contrast to its transcriptional activator role in seedlings. Binding motif-enrichment analyses indicate that FHY3 may coregulate flower development with three flower-specific MADS-domain TFs and four basic helix-loop-helix TFs that are involved in photomorphogenesis. We further demonstrate that CLV3, SEPALLATA1 (SEP1), and SEP2 are FHY3 target genes. In shoot apical meristem, FHY3 directly represses CLV3, which consequently regulates WUS to maintain the stem cell pool. Intriguingly, CLV3 expression did not change significantly in fhy3 and phytochrome B mutants before and after light treatment, indicating that FHY3 and phytochrome B are involved in light-regulated meristem activity. In FM, FHY3 directly represses CLV3, but activates SEP2, to ultimately promote FM determinacy. Taken together, our results reveal insights into the mechanisms of meristem maintenance and determinacy, and illustrate how the roles of a single TF may vary in different organs and developmental stages

An E2-E3 pair contributes to seed size control in grain crops

Abstract Understanding the molecular mechanisms that regulate grain yield is important for improving agricultural productivity. Protein ubiquitination controls various aspects of plant growth but lacks understanding on how E2-E3 enzyme pairs impact grain yield in major crops. Here, we identified a RING-type E3 ligase SGD1 and its E2 partner SiUBC32 responsible for grain yield control in Setaria italica. The conserved role of SGD1 was observed in wheat, maize, and rice. Furthermore, SGD1 ubiquitinates the brassinosteroid receptor BRI1, stabilizing it and promoting plant growth. Overexpression of an elite SGD1 haplotype improved grain yield by about 12.8% per plant, and promote complex biological processes such as protein processing in endoplasmic reticulum, stress responses, photosystem stabilization, and nitrogen metabolism. Our research not only identifies the SiUBC32-SGD1-BRI1 genetic module that contributes to grain yield improvement but also provides a strategy for exploring key genes controlling important traits in Poaceae crops using the Setaria model system