Constructing Physical and Genomic Maps for Puccinia striiformis f. sp. tritici, the Wheat Stripe Rust Pathogen, by Comparing Its EST Sequences to the Genomic Sequence of P. graminis f. sp. tritici, the Wheat Stem Rust Pathogen

The wheat stripe rust fungus, Puccinia striiformis f. sp. tritici (Pst), does not have a known alternate host for sexual reproduction, which makes it impossible to study gene linkages through classic genetic and molecular mapping approaches. In this study, we compared 4,219 Pst expression sequence tags (ESTs) to the genomic sequence of P. graminis f. sp. tritici (Pgt), the wheat stem rust fungus, using BLAST searches. The percentages of homologous genes varied greatly among different Pst libraries with 54.51%, 51.21%, and 13.61% for the urediniospore, germinated urediniospore, and haustorial libraries, respectively, with an average of 33.92%. The 1,432 Pst genes with significant homology with Pgt sequences were grouped into physical groups corresponding to 237 Pgt supercontigs. The physical relationship was demonstrated by 12 pairs (57%), out of 21 selected Pst gene pairs, through PCR screening of a Pst BAC library. The results indicate that the Pgt genome sequence is useful in constructing Pst physical maps

Analysis of pre- and post-mine closure surface deformations in western xuzhou coalfield from 2006 to 2018

Economic development and population expansion in mining cities have led to a growing scarcity of land for construction and thus the closed mines land reuse is extremely urgent. Exploration of the law of surface deformation in closed mine is therefore significance for the development of mining cities. In this study, we first used the StaMSBAS technique to reveal surface deformation of western Xuzhou coalfield from 16/6/2006 to 19/8/2018, based on 77 SAR images. The result of ALOS-1 monitoring was validated by levelling data, and it was shown that the root-mean-square-error and standard deviation were 31.8 mm and 28.9 mm, respectively. The law of surface deformation that occurred before and after mine closure was finally analysed. It was found that: 1) After mine closure, the surface deformation of Jiahe mine experienced the process of subsidence, relative stability and then uplift, and the surface deformations of Zhangxiaolou and Pangzhuang mines changed from slow subsidence to accelerated subsidence. 2) Where the maximum pre-closure subsidence occurred at Jiahe mine, the residual subsidence and uplift that occurred after mine closure was also significant, the correlation coefficients were 0.62 and 0.65, respectively. When the mines were active, surface subsidence of Jiahe and Zhangxiaolou mines was positively correlated with the strike mining degree, with correlation coefficients of 0.90 and 0.83, respectively. After Jiahe mine closure, the residual subsidence was positively correlated with the strike mining degree, and the surface uplift was positively correlated with the depth-to-thickness ratio, the correlation coefficients were both 0.70.Peer ReviewedPostprint (published version

Analysis on spatial heterogeneity of ecological restoration demand in resource-based cities: taking Jiawang District of Xuzhou city as an example

After a long period of coal resource exploitation in resource-based cities, the imbalance and disharmony between resource development and ecological protection in coal mining areas are prominent. In the context of ecological civilization construction, clarifying the spatial heterogeneity of ecological restoration needs and reasonably arranging the priority of ecological restoration work will become the basic work for efficient and coordinated ecological protection and restoration, which will help to plan as a whole, coordinate and orderly promote the high-quality sustainable development of resource-based cities. From the comprehensive perspective of the coordinated development of ecosystem and human well-being, Jiawang District, Xuzhou City, was selected as an example, and the historical remote sensing images, historical mine information and social and economic statistics in 2000, 2010 and 2019 were taken as the data sources. The equivalent assignment method was used to calculate the regional ecosystem service value and make coefficient correction. The landscape ecological risk assessment system was constructed by integrating the topographic location index, mining area disturbance index and landscape vulnerability index. The spatial and temporal patterns of ecosystem service value and ecological risk index in the study area were analyzed, and the sharpe ratio was introduced to further explore the spatial heterogeneity of ecological restoration needs. The results showed that: ① From 2000 to 2019, the total value of ecosystem services in Jiawang district increased first and then decreased, and the value of ecological risk index decreased first and then increased. The growth rate was relatively flat, showing a small range; the spatial distribution of ecological service value and ecological risk level shows a trend of overall connectivity, with local circles moving outward. Urbanization and coal mining subsidence land management are the main factors influencing the spatial pattern differentiation. ② At the quantitative level, the ecosystem service value per unit area and the ecological risk index have strong negative grade correlations, but there is no obvious functional relationship; At the spatial level, the overall Moran’s I index of unit ecosystem service value and ecological risk index in Jiawang District from 2000 to 2019 were negative, showing negative spatial correlation. Ecological risks and ecosystem services have obvious dislocation characteristics. ③ The heterogeneity index R of ecological restoration demand in Jiawang district presents a gradient spatial change trend to a certain extent, and the overall ecological restoration demand tends to decrease, but the R index is still too high or too low in some regions; with the increase of degree of deviation, the range of high value areas for ecological restoration needs gradually narrowed and transformed to low value areas, and the areas requiring key ecological construction tend to be more centralized. The research conclusion can provide reference for the decision-making arrangement of systematic and integrated ecological restoration of resource exhausted cities

Polysulfide-mediated solvation shell reorganization for fast Li+ transfer probed by in-situ sum frequency generation spectroscopy

Understanding of interfacial Li$^+$ solvation shell structures and dynamic evolution at the electrode/electrolyte interface is requisite for developing high-energy-density Li batteries. Herein, the reorganization of Li$^+$ solvation shell at the sulfur/electrolyte interface along with the presence of a trace amount of lithium polysulfides is verified by in-situ sum frequency generation (SFG) spectroscopy together with density functional theory (DFT) calculations. Both the spectroelectrochemical and DFT calculation results reveal a strongly competitive anion adsorption of the polysulfide anion additive against the pristine electrolyte anion on the sulfur cathode surface, reorganizing the interfacial local solvation shell structure facilitating rapid Li ion transfer and conduction. Meanwhile, the evolution of the SFG signals along with the discharging/charging cycle exhibits improved reversibility, indicating the transformation of the inner Helmholtz plane layer into a stable molecular-layer polysulfide interphase rather than a dynamic diffusion layer. Consequently, applications in practical Li-S batteries reveal the capacity and cycling stability of the corresponding cells are significantly enhanced. Our work provides a methodology using in-situ SFG for probing solvation reorganization of charge carriers at electrochemical interfaces

Interfacial “Single‐Atom‐in‐Defects” Catalysts Accelerating Li + Desolvation Kinetics for Long‐Lifespan Lithium‐Metal Batteries

The lithium-metal anode is a promising candidate for realizing high-energy-density batteries owing to its high capacity and low potential. However, several rate-limiting kinetic obstacles, such as the desolvation of Li+ solvation structure to liberate Li$^+$, Li$^0$ nucleation, and atom diffusion, cause heterogeneous spatial Li-ion distribution and fractal plating morphology with dendrite formation, leading to low Coulombic efficiency and depressive electrochemical stability. Herein, differing from pore sieving effect or electrolyte engineering, atomic iron anchors to cation vacancy-rich Co$_{1−xS}$ embedded in 3D porous carbon (SAFe/CVRCS@3DPC) is proposed and demonstrated as catalytic kinetic promoters. Numerous free Li ions are electrocatalytically dissociated from the Li$^+$ solvation complex structure for uniform lateral diffusion by reducing desolvation and diffusion barriers via SAFe/CVRCS@3DPC, realizing smooth dendrite-free Li morphologies, as comprehensively understood by combined in situ/ex situ characterizations. Encouraged by SAFe/CVRCS@3DPC catalytic promotor, the modified Li-metal anodes achieve smooth plating with a long lifespan (1600 h) and high Coulombic efficiency without any dendrite formation. Paired with the LiFePO$_4$ cathode, the full cell (10.7 mg cm$^{−2}$) stabilizes a capacity retention of 90.3% after 300 cycles at 0.5 C, signifying the feasibility of using interfacial catalysts for modulating Li behaviors toward practical applications

An ancestral NB-LRR with duplicated 3'UTRs confers stripe rust resistance in wheat and barley.

Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a global threat to wheat production. Aegilops tauschii, one of the wheat progenitors, carries the YrAS2388 locus for resistance to Pst on chromosome 4DS. We reveal that YrAS2388 encodes a typical nucleotide oligomerization domain-like receptor (NLR). The Pst-resistant allele YrAS2388R has duplicated 3' untranslated regions and is characterized by alternative splicing in the nucleotide-binding domain. Mutation of the YrAS2388R allele disrupts its resistance to Pst in synthetic hexaploid wheat; transgenic plants with YrAS2388R show resistance to eleven Pst races in common wheat and one race of P. striiformis f. sp. hordei in barley. The YrAS2388R allele occurs only in Ae. tauschii and the Ae. tauschii-derived synthetic wheat; it is absent in 100% (n = 461) of common wheat lines tested. The cloning of YrAS2388R will facilitate breeding for stripe rust resistance in wheat and other Triticeae species

Genome-wide QTL mapping for stripe rust resistance in spring wheat line PI 660122 using the Wheat 15K SNP array

IntroductionStripe rust is a global disease of wheat. Identification of new resistance genes is key to developing and growing resistant varieties for control of the disease. Wheat line PI 660122 has exhibited a high level of stripe rust resistance for over a decade. However, the genetics of stripe rust resistance in this line has not been studied. A set of 239 recombinant inbred lines (RILs) was developed from a cross between PI 660122 and an elite Chinese cultivar Zhengmai 9023.MethodsThe RIL population was phenotyped for stripe rust response in three field environments and genotyped with the Wheat 15K single-nucleotide polymorphism (SNP) array.ResultsA total of nine quantitative trait loci (QTLs) for stripe rust resistance were mapped to chromosomes 1B (one QTL), 2B (one QTL), 4B (two QTLs), 4D (two QTLs), 6A (one QTL), 6D (one QTL), and 7D (one QTL), of which seven QTLs were stable and designated as QYrPI660122.swust-4BS, QYrPI660122.swust-4BL, QYrPI660122.swust-4DS, QYrPI660122.swust-4DL, QYrZM9023.swust-6AS, QYrZM9023.swust-6DS, and QYrPI660122.swust-7DS. QYrPI660122.swust-4DS was a major all-stage resistance QTL explaining the highest percentage (10.67%–20.97%) of the total phenotypic variation and was mapped to a 12.15-cM interval flanked by SNP markers AX-110046962 and AX-111093894 on chromosome 4DS.DiscussionThe QTL and their linked SNP markers in this study can be used in wheat breeding to improve resistance to stripe rust. In addition, 26 lines were selected based on stripe rust resistance and agronomic traits in the field for further selection and release of new cultivars

Genome-wide association study of common resistance to rust species in tetraploid wheat

Rusts of the genus Puccinia are wheat pathogens. Stem (black; Sr), leaf (brown; Lr), and stripe (yellow; Yr) rust, caused by Puccinia graminis f. sp. tritici (Pgt), Puccinia triticina (Pt), and Puccinia striiformis f. sp. tritici (Pst), can occur singularly or in mixed infections and pose a threat to wheat production globally in terms of the wide dispersal of their urediniospores. The development of durable resistant cultivars is the most sustainable method for controlling them. Many resistance genes have been identified, characterized, genetically mapped, and cloned; several quantitative trait loci (QTLs) for resistance have also been described. However, few studies have considered resistance to all three rust pathogens in a given germplasm. A genome-wide association study (GWAS) was carried out to identify loci associated with resistance to the three rusts in a collection of 230 inbred lines of tetraploid wheat (128 of which were Triticum turgidum ssp. durum) genotyped with SNPs. The wheat panel was phenotyped in the field and subjected to growth chamber experiments across different countries (USA, Mexico, Morocco, Italy, and Spain); then, a mixed linear model (MLM) GWAS was performed. In total, 9, 34, and 5 QTLs were identified in the A and B genomes for resistance to Pgt, Pt, and Pst, respectively, at both the seedling and adult plant stages. Only one QTL on chromosome 4A was found to be effective against all three rusts at the seedling stage. Six QTLs conferring resistance to two rust species at the adult plant stage were mapped: three on chromosome 1B and one each on 5B, 7A, and 7B. Fifteen QTLs conferring seedling resistance to two rusts were mapped: five on chromosome 2B, three on 7B, two each on 5B and 6A, and one each on 1B, 2A, and 7A. Most of the QTLs identified were specific for a single rust species or race of a species. Candidate genes were identified within the confidence intervals of a QTL conferring resistance against at least two rust species by using the annotations of the durum (cv. ‘Svevo’) and wild emmer wheat (‘Zavitan’) reference genomes. The 22 identified loci conferring resistance to two or three rust species may be useful for breeding new and potentially durable resistant wheat cultivars

Reduced electron recombination of dye-sensitized solar cells based on TiO2 spheres consisting of ultrathin nanosheets with [001] facet exposed

An anatase TiO 2 material with hierarchically structured spheres consisting of ultrathin nanosheets with 100% of the [001] facet exposed was employed to fabricate dye-sensitized solar cells (DSC s). Investigation of the electron transport and back reaction of the DSCs by electrochemical impedance spectroscopy showed that the spheres had a threefold lower electron recombination rate compared to the conventional TiO 2 nanoparticles. In contrast, the effective electron diffusion coefficient, D n, was not sensitive to the variation of the TiO 2 morphology. The TiO 2 spheres showed the same Dn as that of the nanoparticles. The influence of TiCl 4 post-treatment on the conduction band of the TiO 2 spheres and on the kinetics of electron transport and back reactions was also investigated. It was found that the TiCl 4 post-treatment caused a downward shift of the TiO 2 conduction band edge by 30 meV. Meanwhile, a fourfold increase of the effective electron lifetime of the DSC was also observed after TiCl4 treatment. The synergistic effect of the variation of the TiO 2 conduction band and the electron recombination determined the open-circuit voltage of the DSC. © 2012 Wang et al