Natural variation in ZmGRF10 regulates tolerance to phosphate deficiency in maize by modulating phosphorus remobilization

Phosphorus is a limiting factor in agriculture due to restricted availability in soil and low utilization efficiency of crops.The identification of superior haplotypes of key genes responsible for low-phosphate(Pi)tolerance and their natural variation is important for molecular breeding.In this study,we conducted genome-wide association studies on low-phosphate tolerance coefficients using 152 maize inbred lines,and identified a significant association between SNPs on chromosome 7 and a low-phosphate tolerance coefficient.ZmGRF10 was identified as a candidate gene involved in adaptation of maize to Pi starvation.Expression of ZmGRF10 is induced by Pi starvation.A mutation in ZmGRF10 alleviated Pi starvation stress.RNA-seq analyses revealed significant upregulation of genes encoding various phosphatases in the zmgrf10-1 mutant,suggesting that ZmGRF10 negatively regulates expression of these genes,thereby affecting low-Pi tolerance by suppressing phosphorus remobilization.A superior haplotype with variations in the promoter region exhibited lower transcription activity of ZmGRF10.Our study unveiled a novel gene contributing to tolerance to low-Pi availability with potential to benefit molecular breeding for high Pi utilization.

Sr-doping effects on La_2O_3 catalyst for oxidative coupling of methane

Density‐functional theory calculations were carried out to study the strontium(Sr)‐doping effect on methane activation over a lanthanum‐oxide(La2O3)catalyst for the oxidative coupling of methane(OCM)using the cluster model.Eight Sr‐doped La2O3cluster models were built from pure La2O3clusters that were used previously to model the La2O3catalyst.These form two distinct categories,namely,those without a radical character(LaSrO2(OH),La2SrO4,La3SrO5(OH),and La5SrO8(OH))and those with a radical character(LaSrO3,La2SrO4(OH),La3SrO6,and La5SrO9).The potential‐energy surface for CH4activation to form a CH3radical at different Sr-O and La-O pair sites on these Sr‐doped La2O3clusters was calculated to study the Sr‐doping effect on the OCM catalytic activity.CH4physisorption and chemisorption energies,and activation barriers,and CH3desorption energies were predicted.Compared with the pure La2O3clusters,in general,the Sr‐doped La2O3clusters are thermodynamically and kinetically more reactive with CH4.For the Sr‐doped La2O3clusters without the radical character,the Sr-O pair site is more reactive with CH4than the La-O pair site,although a direct release of the CH3radical is also highly endothermic as in the case of the pure La2O3clusters.In contrast,for the Sr‐doped La2O3clusters with a radical character,the activation of CH4at the oxygen radical site and the release of the CH3radical are much easier.Thus,our calculations suggest that the Sr dopant prompts the OCM catalytic activity of the La2O3catalyst by providing a highly active oxygen‐radical site and by strengthening the basicity of the M-O pair site,which leads to lower CH4activation energies and lower CH3desorption energies.

Effect of Pd doping on CH_4 reactivity over Co_3O_4 catalysts from density-functional theory calculations

Palladium oxide(PdOx)and cobalt oxide(Co3O4)are efficient catalysts for methane(CH4)combustion,and Pd‐doped Co3O4catalysts have been found to exhibit better catalytic activities,which suggest synergism between the two components.We carried out first‐principles calculations at the PBE+U level to investigate the Pd‐doping effect on CH4reactivity over the Co3O4catalyst.Because of the structural complexity of the Pd‐doped Co3O4catalyst,we built Pd‐doped catalyst models using Co3O4(001)slabs with two different terminations and examined CH4reactivity over the possible Pd?O active sites.A low energy barrier of0.68eV was predicted for CH4dissociation over the more reactive Pd‐doped Co3O4(001)surface,which was much lower than the0.98and0.89eV that was predicted previously over the more reactive pure Co3O4(001)and(011)surfaces,respectively.Using a simple model,we predicted CH4reaction rates over the pure Co3O4(001)and(011)surfaces,and Co3O4(001)surfaces with different amounts of Pd dopant.Our theoretical results agree well with the available experimental data,which suggests a strong synergy between the Pd dopant and the Co3O4catalyst,and leads to a significant increase in CH4reaction rate.

Low temperature surface oxygen activation in crystalline MnO_(2) triggered by lattice confined Pd single atoms

Tuning the coordination environment is the research axis of single atom catalysts (SACs). SACs are commonly stabilized by various defects from support. Here, we report a lattice confined Pd SAC using MnO_(2) as support. Compared with the Pd clusters anchored on the surface, the lattice confined Pd single atoms allows spontaneous exaction of surrounding lattice oxygen at room temperature when employed in CO oxidation. The MnO_(2) supported Pd SAC exhibited a high turnover frequency of 0.203 s^(−1) at low reaction temperature, which is higher than that of recently reported Pd SACs. Theoretical calculations also confirmed the confined monatomic Pd activate lattice oxygen with an ultralow energy barrier. Our results illustrate that the unique coordination environment of single atom provided by lattice confinement is promising to boost the activity of SACs.

Bonding strength of graded anti-corrosive coatings of fluoroethylenepropylene (FEP)/polyphenylene sulfide (PPS)

Fluororesin-based anti-corrosive coatings including graded FEP/PPS were prepared on carbon steel by melt powder coating, the bonding strength of all coating systems was determined by the pull-off test. It is found that the poor adhesion of fluororesin coatings to metallic substrates is improved obviously by the graded coating structure of FEP/PPS, and the bonding strength reaches up to 11.8 MPa for the five-layer system. Examination by electron probe microanalysis （EPMA） verifies that the distribution of main components is graded in the five-layer system, which is responsible for the enhancement of the interfacial bonding.

Improvement of Cemented Gangue Backfill Material with Barium Hydroxide in Acid Mine Water

As a kind of green concrete,the mechanical properties and durability of cemented gangue backfill material(CGBM)will be affected if they are in acid mine water with sulfate ions in the long term.To improve the performance of CGBM in acid mine water with sulfate ions,CGBM specimens with different doses of barium hydroxide were immersed in sulfuric acid solutions of different concentrations for 270 days.The changes of mass,ultrasonic pulse velocity(UPV)and compressive strength of the specimens at different ages were analyzed.Scanning electron microscopy(SEM)and X-ray diffraction(XRD)were used to analyze the microstructure and composition of the specimens.The results show that incorporation of barium hydroxide into CGBM specimen can promote the formation of barium sulfate precipitation and inhibit the generation of corrosion products such as ettringite.Meanwhile,barium sulfate precipitation blocks the pore channel invaded by sulfuric acid solution,delaying the progress of corrosion reaction and making the interior of CGBM specimen more complete.And the specimen with 2.0 kg/m^(3)barium hydroxide was more effective in improving performance.This study provides a basis for the ratio design of CGBM in acid mine water with sulfate ions.

BrDDB1A maintains regular growth of Chinese cabbage via UV tolerance

Normal plant growth and development ensures the timely maturity and expected yield of crops.The repair mechanism of genome damage under adverse circumstances is essential for maintaining regular plant growth.Herein,two allelic growth retardation mutants of Chinese cabbage,grm1 and grm2,were obtained from EMS-mutagenized populations of wild-type'FT'isolated-cultured microspores and seeds,respectively.Both mutants stably inherited and exhibited stunted growth with smaller leafy-heads.Genetic analysis and allelism test manifested that the mutated trait was triggered by a same single recessive nuclear gene.Via BSR-Seq,Brgrm1 was mapped to a target region including 20 genes on chromosome A09.Whole-genome re-sequencing revealed that BraA09g024830.3C in grm1 had a single base(A)deletion in the 17th exon,leading to a termination codon(TAG).Genotyping showed that the mutated phenotype co-segregated with the InDel in recombinants of the closest linkage markers.In addition,cloning of BraA09g024830.3C in grm2 found that a base substitution(G-A)occurred in the last base of the 1st intron causing an additional 263-bp retention in coding sequences,which in turn led to a termination codon(TAA).BraA09g024830.3C(BrDDB1A)is a homolog of Arabidopsis thaliana Damaged DNA Binding Protein 1A(DDB1A),a key gene of UV tolerance involved in DNA damage repair.The two mutants exhibited normal plant growth identical with wild-type under an extremely low UV radiation.Our results demonstrated that BrDDB1A contributes to maintaining regular plant growth in Chinese cabbage,which provide insights into elucidating the molecular mechanism underlying Chinese cabbage growth and development.

A universal direct tensile testing method for measuring the tensile strength of rocks

There is limited applicability to the current method for testing the direct tensile strength of rocks because it places stringent requirements on the testing equipment.This work suggests a universal method based on the‘‘compression-to-tensiono idea in response to these difficulties.By applying pressure,this technique makes it possible to test the tensile strength of rocks directly with any conventional compression test machines.Granite was utilized as the test material in order to validate this suggested testing method,and the results showed what follows.Upon determining the true fracture area through digital reconstruction,an average calculated tensile strength of 5.97 MPa with a Cvof 0.04 was obtained.There is a positive correlation between tensile strength and the joint roughness coefficient(JRC)of the failure surface.The aggregation mode of AE events with the loading process conforms to the damage characteristics of rock tensile failure.The direct tensile testing method proposed in this study not only has high universality but also produces test results with outstanding consistency.Additionally,factors influencing the results of the tensile test are pointed out,and recommendations for optimizing the suggested testing method are offered.

探地雷达在水下考古中的机遇与挑战

伴随着我国水下文化遗产专项调查的全面开展,水下考古正面临着一个重要的发展契机。水下摄影、声学及磁法等是水下考古的主要探测方法。然而,对于淹埋在水下地层内的文物遗存,侧扫声呐及多波束难以发挥出其优势;而浅水域的多次波现象也严重制约了浅剖仪对深埋目标的辨识;同样,基于磁性异常的探测方法也因体积效应而难以分辨小尺度目标。因此,迫切要求有更高分辨力及更高适应能力的探测方法来为考古学者提供精准的水下文物空间分布信息。本文从水下考古探测方法的发展与现状入手,通过对水域雷达探测案例的整理,以上林湖后司岙水域水下考古为切入点,引入利用探地雷达开展水下考古探测的思想,结合实际应用,剖析探地雷达在水下考古领域中的机遇与挑战。

分成激励、预算约束与地方政府征税行为

本文首先通过一个地方最优征税模型,分析了税收分成和财政压力对地方税收努力的影响机制及其在税收努力选择上的空间策略竞争行为。在此基础上,基于PSFA方法测算了我国各地方政府的实际税收努力水平,结果显示东部地区明显高于中西部,但地区差距在不断缩小。实证分析结果显示,税收分成增加会激励当地政府提高税收努力,财政压力则倒逼政府加强税收征管;税收努力在地区之间存在策略模仿式的竞争,财政压力的传导则与本地税收努力存在策略替代。本文的研究意味着,要规范地方政府的征税行为,不仅应健全财力与支出责任相匹配的预算体制,还应加强区域间财政关系的协调合作,构建激励与约束兼容的新型地区间财政收入分配制度。

Upregulation of Chemokine CXCL12 in the Dorsal Root Ganglia and Spinal Cord Contributes to the Development and Maintenance of Neuropathic Pain Following Spared Nerve Injury in Rats

Emerging evidence indicates that CXCL12/ CXCR4 signaling is involved in chronic pain. However, few studies have systemically assessed its role in direct nerve injury-induced neuropathic pain and the underlying mech- anism. Here, we determined that spared nerve injury （SNI） increased the expression of CXCL12 and its cognate receptor CXCR4 in lumbar 5 dorsal root ganglia （DRG） neurons and satellite glial cells. SNI also induced long- lasting upregulation of CXCL12 and CXCR4 in the ipsi- lateral L4-5 spinal cord dorsal horn, characterized by CXCL12 expression in neurons and microglia, and CXCR4 expression in neurons and astrocytes. Moreover, SNI- induced a sustained increase in TNF-α expression in the DRG and spinal cord. Intraperitoneal injection （i.p.） of the TNF-α synthesis inhibitor thalidomide reduced the SNI-in- duced mechanical hypersensitivity and inhibited the expression of CXCL12 in the DRG and spinal cord. Intrathecal injection （i.t.） of the CXCR4 antagonist AMD3100, both 30 rain before and 7 days after SNI, reduced the behavioral signs of allodynia. Rats given an i.t. or i.p. bolus of AMD3100 on day 8 of SNI exhibited attenuated abnormal pain behaviors. The neuropathic pain established following SNI was also impaired by i.t. admin- istration of a CXCL12-neutralizing antibody. Moreover, repetitive i.t. AMD3100 administration prevented the acti- vation of ERK in the spinal cord. The mechanical hyper- sensitivity induced in nai＇ve rats by i.t. CXCL12 was alleviated by pretreatment with the MEK inhibitor PD98059. Collectively, our results revealed that TNF-α might mediate the upregulation of CXCL12 in the DRG and spinal cord following SNI, and that CXCL 12/CXCR4 sig- naling via ERK activation contributes to the development and maintenance of neuropathic pain.

Global Co-transcriptional Splicing in Arabidopsis and the Correlation with Splicing Regulation in Mature RNAs

RNA splicing and spliceosome assembly in eukaryotes occur mainly during transcription.However,co-transcriptional splicing has not yet been explored in plants.Here,we built transcriptomes of nascent chromatin RNAs in Arabidopsis thaliana and showed that nearly all introns undergo co-transcriptional splicing,which occurs with higher efficiency for introns in protein-coding genes than for those in noncoding RNAs.Total intron number and intron position are two predominant features that correlate with co-transcriptional splicing efficiency,and introns with alternative 5′or 3′splice sites are less efficiently spliced.Furthermore,we found that mutations in genes encoding trans-acting proteins lead to more introns with increased splicing defects in nascent RNAs than in mature RNAs,and that introns with increased splicing defects in mature RNAs are inefficiently spliced at the co-transcriptional level.Collectively,our results not only uncovered widespread co-transcriptional splicing in Arabidopsis but also identified features that may affect or be affected by co-transcriptional splicing efficiency.