Nitrogen(N), phosphorus(P), and potassium(K) are essential macronutrients that are crucial not only for maize growth and development, but also for crop yield and quality. The genetic basis of macronutrient dynamics an...Nitrogen(N), phosphorus(P), and potassium(K) are essential macronutrients that are crucial not only for maize growth and development, but also for crop yield and quality. The genetic basis of macronutrient dynamics and accumulation during grain filling in maize remains largely unknown. In this study, we evaluated grain N, P, and K concentrations in 206 recombinant inbred lines generated from a cross of DH1M and T877 at six time points after pollination. We then calculated conditional phenotypic values at different time intervals to explore the dynamic characteristics of the N, P, and K concentrations. Abundant phenotypic variations were observed in the concentrations and net changes of these nutrients. Unconditional quantitative trait locus(QTL) mapping revealed 41 non-redundant QTLs, including 17, 16, and 14 for the N, P, and K concentrations, respectively. Conditional QTL mapping uncovered 39 non-redundant QTLs related to net changes in the N, P, and K concentrations. By combining QTL, gene expression, co-expression analysis, and comparative genomic data, we identified 44, 36, and 44 candidate genes for the N, P, and K concentrations, respectively, including GRMZM2G371058 encoding a Doftype zinc finger DNA-binding family protein, which was associated with the N concentration, and GRMZM2G113967encoding a CBL-interacting protein kinase, which was related to the K concentration. The results deepen our understanding of the genetic factors controlling N, P, and K accumulation during maize grain development and provide valuable genes for the genetic improvement of nutrient concentrations in maize.展开更多
In a study of DNA methylation changes in melatonin-deficient rice mutants,mutant plants showed premature leaf senescence during grain-filling and reduced grain yield.Melatonin deficiency led to transcriptional reprogr...In a study of DNA methylation changes in melatonin-deficient rice mutants,mutant plants showed premature leaf senescence during grain-filling and reduced grain yield.Melatonin deficiency led to transcriptional reprogramming,especially of genes involved in chlorophyll and carbon metabolism,redox regulation,and transcriptional regulation,during dark-induced leaf senescence.Hypomethylation of mCG and mCHG in the melatonin-deficient rice mutants was associated with the expression change of both protein-coding genes and transposable element-related genes.Changes in gene expression and DNA methylation in the melatonin-deficient mutants were compensated by exogenous application of melatonin.A decreased S-adenosyl-L-methionine level may have contributed to the DNA methylation variations in rice mutants of melatonin deficiency under dark conditions.展开更多
The nutritional composition and overall quality of maize kernels are largely determined by the key chemical com-ponents:protein,oil,and starch.Nevertheless,the genetic basis underlying these nutritional quality traits...The nutritional composition and overall quality of maize kernels are largely determined by the key chemical com-ponents:protein,oil,and starch.Nevertheless,the genetic basis underlying these nutritional quality traits during grainfilling remains poorly understood.In this study,the concentrations of protein,oil,and starch were studied in 204 recombinant inbred lines resulting from a cross between DH1M and T877 at four different stages post-pollination.All the traits exhibited considerable phenotypic variation.During the grain-filling stage,the levels of protein and starch content generally increased,whereas oil content decreased,with significant changes observed between 30 and 40 days after pollination.Quantitative trait locus(QTL)mapping was conducted and a total of 32 QTLs,comprising 14,12,and 6 QTLs for grain protein,oil,and starch content were detected,respectively.Few QTLs were consistently detectable across different time points.By integrating QTL analysis,glo-bal gene expression profiling,and comparative genomics,we identified 157,86,and 54 differentially expressed genes harboring nonsynonymous substitutions between the parental lines for grain protein,oil,and starch con-tent,respectively.Subsequent gene function annotation prioritized 15 candidate genes potentially involved in reg-ulating grain quality traits,including those encoding transcription factors(NAC,MADS-box,bZIP,and MYB),cell wall invertase,cellulose-synthase-like protein,cell division cycle protein,trehalase,auxin-responsive factor,and phloem protein 2-A13.Our study offers significant insights into the genetic architecture of maize kernel nutritional quality and identifies promising QTLs and candidate genes,which are crucial for the genetic enhance-ment of these traits in maize breeding programs.展开更多
Rice(Oryza sativa)provides a staple food source for more than half the world population.However,the current pace of rice breeding in yield growth is insufficient to meet the food demand of the everincreasing global po...Rice(Oryza sativa)provides a staple food source for more than half the world population.However,the current pace of rice breeding in yield growth is insufficient to meet the food demand of the everincreasing global population.Genomic selection(GS)holds a great potential to accelerate breeding progress and is cost-effective via early selection before phenotypes are measured.Previous simulation and experimental studies have demonstrated the usefulness of GS in rice breeding.However,several affecting factors and limitations require careful consideration when performing GS.In this review,we summarize the major genetics and statistical factors affecting predictive performance as well as current progress in the application of GS to rice breeding.We also highlight effective strategies to increase the predictive ability of various models,including GS models incorporating functional markers,genotype by environment interactions,multiple traits,selection index,and multiple omic data.Finally,we envision that integrating GS with other advanced breeding technologies such as unmanned aerial vehicles and open-source breeding platforms will further improve the efficiency and reduce the cost of breeding.展开更多
Dissecting the genetic architecture of complex traits is an ongoing challenge for geneticists.Two complementary approaches for genetic mapping,linkage mapping and association mapping have led to successful dissection ...Dissecting the genetic architecture of complex traits is an ongoing challenge for geneticists.Two complementary approaches for genetic mapping,linkage mapping and association mapping have led to successful dissection of complex traits in many crop species.Both of these methods detect quantitative trait loci(QTL) by identifying marker–trait associations,and the only fundamental difference between them is that between mapping populations,which directly determine mapping resolution and power.Based on this difference,we first summarize in this review the advances and limitations of family-based mapping and natural population-based mapping instead of linkage mapping and association mapping.We then describe statistical methods used for improving detection power and computational speed and outline emerging areas such as large-scale meta-analysis for genetic mapping in crops.In the era of next-generation sequencing,there has arisen an urgent need for proper population design,advanced statistical strategies,and precision phenotyping to fully exploit high-throughput genotyping.展开更多
Many complex traits are highly correlated rather than independent. By taking the correlation structure of multiple traits into account, joint association analyses can achieve both higher statistical power and more acc...Many complex traits are highly correlated rather than independent. By taking the correlation structure of multiple traits into account, joint association analyses can achieve both higher statistical power and more accurate estimation. To develop a statistical approach to joint association analysis that includes allele detection and genetic effect estimation, we combined multivariate partial least squares regression with variable selection strategies and selected the optimal model using the Bayesian Information Criterion(BIC). We then performed extensive simulations under varying heritabilities and sample sizes to compare the performance achieved using our method with those obtained by single-trait multilocus methods. Joint association analysis has measurable advantages over single-trait methods, as it exhibits superior gene detection power, especially for pleiotropic genes. Sample size, heritability,polymorphic information content(PIC), and magnitude of gene effects influence the statistical power, accuracy and precision of effect estimation by the joint association analysis.展开更多
Stalk strength increases resistance to stalk lodging,which causes maize(Zea mays L.)production losses worldwide.The genetic mechanisms regulating stalk strength remain unclear.In this study,three stalk strength-relate...Stalk strength increases resistance to stalk lodging,which causes maize(Zea mays L.)production losses worldwide.The genetic mechanisms regulating stalk strength remain unclear.In this study,three stalk strength-related traits(rind penetrometer resistance,stalk crushing strength,and stalk bending strength)and four plant architecture traits(plant height,ear height,stem diameter,stem length)were measured in three field trials.Substantial phenotypic variation was detected for these traits.A genome-wide association study(GWAS)was conducted using general and mixed linear models and 372,331 single-nucleotide polymorphisms(SNPs).A total of 94 quantitative trait loci including 241 SNPs were detected.By combining the GWAS data with public gene expression data,56 candidate genes within 50 kb of the significant SNPs were identified,including genes encoding flavonol synthase(GRMZM2G069298,ZmFLS2),nitrate reductase(GRMZM5G878558,ZmNR2),glucose-1-phosphate adenylyltransferase(GRMZM2G027955),and laccase(GRMZM2G447271).Resequencing GRMZM2G069298 and GRMZM5G878558 in all tested lines revealed respectively 47 and 2 variants associated with RPR.Comparison of the RPR of the zmnr2EMS mutant and the wild-type plant under high-and low-nitrogen conditions verified the GRMZM5G878558 function.These findings may be useful for clarifying the genetic basis of stalk strength.The identified candidate genes and variants may be useful for the genetic improvement of maize lodging resistance.展开更多
Genomic selection(GS)is a powerful tool for improving genetic gain in maize breeding.However,its routine application in large-scale breeding pipelines is limited by the high cost of genotyping platforms.Although seque...Genomic selection(GS)is a powerful tool for improving genetic gain in maize breeding.However,its routine application in large-scale breeding pipelines is limited by the high cost of genotyping platforms.Although sequencing-based and array-based genotyping platforms have been used for GS,few studies have compared prediction performance among platforms.In this study,we evaluated the predictabilities of four agronomic traits in 305 maize hybrids derived from 149 parental lines subjected to genotyping by sequencing(GBS),a 40K SNP array,and target sequence capture(TSC)using eight GS models.The GBS marker dataset yielded the highest predictabilities for all traits,followed by TSC and SNP array datasets.We investigated the effect of marker density and statistical models on predictability among genotyping platforms and found that 1K SNPs were sufficient to achieve comparable predictabilities to 10K and all SNPs,and BayesB,GBLUP,and RKHS performed well,while XGBoost performed poorly in most cases.We also selected significant SNP subsets using genome-wide association study(GWAS)analyses in three panels to predict hybrid performance.GWAS facilitated selecting effective SNP subsets for GS and thus reduced genotyping cost,but depended heavily on the GWAS panel.We conclude that there is still room for optimization of the existing SNP array,and using genotyping by target sequencing(GBTS)techniques to integrate a few functional markers identified by GWAS into the 1K SNP array holds great promise of being an effective strategy for developing desirable GS breeding arrays.展开更多
As the end products of cellular regulatory processes,metabolites provide the link between genotypes and phenotypes.Althoughmetabolites have been widely applied for functional gene detection and phenotype prediction in...As the end products of cellular regulatory processes,metabolites provide the link between genotypes and phenotypes.Althoughmetabolites have been widely applied for functional gene detection and phenotype prediction in maize,there is little research focusing on the genetic information of metabolites per se.Here,we performed genetic analyses for the kernel metabolites of 11 parental inbred lines of six representative maize varieties,including Zhongdan 2,Danyu 13,Yedan 13,Zhengdan 958,Xianyu 355,and Suyu 16,as well as their 26 reciprocal hybrids.We identified a total of 208 metabolites in maize kernels using untargeted metabolite profiling technology.Both cluster analysis and principal component analysis indicated that kernel metabolites could distinguish hybrids from their parents.Analysis of variance further revealed that 163 metabolites exhibited significant differences between parents and hybrids,and 40 metabolites showed significant differences between reciprocal crosses.We also investigated the genetic effects and heterosis for each metabolite.By taking all hybrids into consideration,about two-thirds of all metabolites displayed overdominant with 36.8%and 31%of them displaying positive overdominant and negative overdominant,respectively.Besides,27.5%and 20.4%of all hybrid combinations showed significant mid-parent heterosis and over-parent heterosis,respectively.Our findings revealed that kernel metabolites exhibited the diversity of relationship between maize hybrids and their parental lines.Additionally,we identified 25 significant metabolicmarkers related to 11 agronomic traits using the LASSO method.Seven metabolic markers were associated with more than one trait simultaneously.These results provide a genetic basis for further utilization of metabolites in the genetic improvement of maize.展开更多
The relative motion of the electrodes is a typical feature of sliding electrical contact systems.The system fault caused by the arc is the key problem that restricts the service life of the sliding electrical contact ...The relative motion of the electrodes is a typical feature of sliding electrical contact systems.The system fault caused by the arc is the key problem that restricts the service life of the sliding electrical contact system.In this paper,an arcing experimental platform that can accurately control the relative speed and distance of electrodes is built,and the influence of different electrode speeds and electrode distances on arc motion characteristics is explored.It is found that there are three different modes of arc root motion:single arc root motion mode,single and double arc roots alternating motion mode,and multiple arc roots motion mode.The physical process and influence mechanism of different arc root motion modes are further studied,and the corresponding relationship between arc root motion modes and electrode speed is revealed.In addition,to further explore the distribution characteristics of arc temperature and its influencing factors,an arc magnetohydrodynamic model under the relative motion of electrodes is established,and the variation law of arc temperature under the effect of different electrode speeds and electrode distances is summarized.Finally,the influence mechanism of electrode speed and electrode distance on arc temperature,arc root distance,and arc root speed is clarified.The research results enrich the research system of arc dynamic characteristics in the field of sliding electrical contact,and provide theoretical support for restraining arc erosion and improving the service life of the sliding electrical contact system.展开更多
Crown root traits,including crown root angle(CRA),diameter(CRD),and number(CRN),are major determining factors of root system architecture,which influences crop production.In maize,the genetic mechanisms determining cr...Crown root traits,including crown root angle(CRA),diameter(CRD),and number(CRN),are major determining factors of root system architecture,which influences crop production.In maize,the genetic mechanisms determining crown root traits in the field are largely unknown.CRA,CRD,and CRN were evaluated in a recombinant inbred line population in three field trials.High phenotypic variation was observed for crown root traits,and all measured traits showed significant genotype–environment interactions.Singleenvironment(SEA)and multi-environment(MEA)quantitative trait locus(QTL)analyses were conducted for CRA,CRD,and CRN.Of 46 QTL detected by SEA,most explained less than 10%of the phenotypic variation,indicating that a large number of minor-effect QTL contributed to the genetic component of these traits.MEA detected 25 QTL associated with CRA,CRD,and CRN,and 2 and 1 QTL were identified with significant QTL-by-environment interaction effects for CRA and CRD,respectively.A total of 26.1%(12/46)of the QTL identified by SEA were also detected by MEA,with many being detected in more than one environment.These findings contribute to our understanding of the phenotypic and genotypic patterns of crown root traits in different environments.The identified environment-specific QTL and stable QTL may be used to improve root traits in maize breeding.展开更多
Simple sequence repeats(SSRs) are important molecular markers for assessing genetic diversity in Arachis hypogaea L. and many other crops and constructing genetic linkage maps for important agricultural traits. In thi...Simple sequence repeats(SSRs) are important molecular markers for assessing genetic diversity in Arachis hypogaea L. and many other crops and constructing genetic linkage maps for important agricultural traits. In this study, 29,357 potential SSRs were identified in 22,806 unigenes assembled from A. hypogaea transcript sequences. Of these unigenes, 1883 and 4103 were annotated and assigned in Kyoto Encyclopedia of Genes and Genomes Orthology and Eukaryotic Orthologous Groups databases, respectively. Among the SSR motifs, mono-(19,065; 64.94%) and trinucleotide(5033; 17.14%) repeats were the most common, and the three most dominant motifs were A/T(18,358; 62.54%), AG/CT(2804;9.55%), and AAG/CTT(1396; 4.76%). Polymerase chain reaction(PCR) primer pairs were designed for 4340 novel SSR markers and 210 new SSRs were validated using 24 A. hypogaea varieties. Of the 210, 191(91%) yielded PCR products, with 37(18%) identifying polymorphisms. The 37 polymorphic SSR markers detected 146 alleles(2–10 alleles per locus), and the average polymorphic information content was 0.403(with a range of 0.077 to0.819). The new SSRs enrich the current marker resources for A. hypogaea and may also be useful for genetic diversity analysis, functional genomics research, and molecular breeding.展开更多
Seed moisture at harvest is a critical trait affecting maize quality and mechanized production,and is directly determined by the dehydration process after physiological maturity.However,the dynamic nature of seed dehy...Seed moisture at harvest is a critical trait affecting maize quality and mechanized production,and is directly determined by the dehydration process after physiological maturity.However,the dynamic nature of seed dehydration leads to inaccurate evaluation of the dehydration process by conventional determination methods.Seed dry weight and fresh weight were recorded at 14 time points after pollination in a recombinant inbred line(RIL)population derived from two inbred lines with contrasting seed dehydration dynamics.The dehydration curves of RILs were determined by fitting trajectories of dry weight accumulation and dry weight/fresh weight ratio change based on a logistic model,allowing the estimation of eight characteristic parameters that can be used to describe dehydration features.Quantitative trait locus(QTL)mapping,taking these parameters as traits,was performed using multiple methods.Single-trait QTL mapping revealed 76 QTL associated with dehydration characteristic parameters,of which the phenotypic variation explained(PVE)was 1.03%to 15.24%.Multipleenvironment QTL analysis revealed 21 related QTL with PVE ranging from 4.23%to 11.83%.Multiple-trait QTL analysis revealed 58 QTL,including 51 pleiotropic QTL.Combining these mapping results revealed 12 co-located QTL and the dehydration process of RILs was divided into three patterns with clear differences in dehydration features.These results not only deepen general understanding of the genetic characteristics of seed dehydration but also suggest that this approach can efficiently identify associated genetic loci in maize.展开更多
For high-voltage direct current(HVDC)power grid transmission with higher voltages,the energyconsuming branch of the DC circuit breaker is required to dissipate huge energies of more than megajoules in a short time in ...For high-voltage direct current(HVDC)power grid transmission with higher voltages,the energyconsuming branch of the DC circuit breaker is required to dissipate huge energies of more than megajoules in a short time in the case of a fault and short circuit.The requirements for huge volume and weight are difficult to meet with energy-consuming equipment based on ZnO.In this paper,a new energy consumption method is proposed based on gallium indium tin(GaInSn)liquid metal in the arcing process,and a test platform with adjustable short-circuit current is built.The mechanism triggering GaInSn liquid metal arcing energy consumption is studied.It is found that short-circuit current and channel aperture are the key parameters affecting the energy consumption of liquid metal arcing.The characteristics of GaInSn liquid metal energy consumption are investigated,and four stages of liquid metal energy consumption are found:oscillatory shrinkage,arc breakdown,arc burning phase change and arc extinction.The influence of short-circuit current and channel aperture on the energy consumption characteristics of GaInSn liquid metal is investigated.To further explore the physical mechanism of the above phenomena,a magneto-hydrodynamic model of energy consumption in the GaInSn liquid metal arcing process is established.The influence of short-circuit current and channel aperture on the temperature distribution of the liquid metal arc is analyzed.The mechanism of the effect of short-circuit current and channel aperture on peak arc temperature and the temperature diffusion rate is clarified.The research results provide theoretical support for this new liquid metal energy consumption mode DC circuit breaker.展开更多
The fault caused by a pantograph-catenary arc is the main factor that threatens the stability of high-speed railway energy transmission.Pantograph-catenary arc vertical drift is more severe than the case under normal ...The fault caused by a pantograph-catenary arc is the main factor that threatens the stability of high-speed railway energy transmission.Pantograph-catenary arc vertical drift is more severe than the case under normal pressure,as it is easy to develop the rigid busbar,which may lead to the flashover occurring around the support insulators.We establish a pantograph-catenary arc experiment and diagnosis platform to simulate low pressure and strong airflow environment.Meanwhile,the variation law of arc drift height with time under different air pressures and airflow velocities is analyzed.Moreover,arc drift characteristics and influencing factors are explored.The physical process of the arc column drifting to the rigid busbar with the jumping mechanism of the arc root on the rigid busbar is summarized.In order to further explore the mechanism of the above physical process,a multi-field stress coupling model is built,as the multi-stress variation law of arc is quantitatively evaluated.The dynamic action mechanism of multi-field stress on arc drifting characteristics is explored,as the physical mechanism of arc drifting under low pressure is theoretically explained.The research results provide theoretical support for arc suppression in high-altitude areas.展开更多
(Molecular Plant 16,1832-1846,November 62023)The originally published version of this manuscript contained several small mistakes in the labels and legends of main and supplemental figures,along with a few small mista...(Molecular Plant 16,1832-1846,November 62023)The originally published version of this manuscript contained several small mistakes in the labels and legends of main and supplemental figures,along with a few small mistakes in the main text,that have now been corrected.Specifically,in Figure 6G,the label“NILGY31^(Pijx)”has been corrected to“NIL^(Pijx)”,and in the legend of Figure 6H,“PPL^(Pijx Piz-t)”and“PPL^(Pijx Pigm)”have been corrected to“NIL^(Piz-t Pijx)”and“PPL^(Pigm Pijx).”In Figure S8A。展开更多
High-speed trains rely on pantograph-catenary systems(PCSs)to collect electrical energy from power systems.However,the dynamic interaction between the pantograph and the catenary system may become mismatched once ice ...High-speed trains rely on pantograph-catenary systems(PCSs)to collect electrical energy from power systems.However,the dynamic interaction between the pantograph and the catenary system may become mismatched once ice accumulates on the overhead conductors.More frequent arcing may occur within the PCS during train operation,posing an unpredictable threat to operational safety.Therefore,it is crucial to evaluate the ability of overhead contact system(OCS)to withstand ice-covered variability during line desgin.A new strategy is proposed to evaluate the adaptive performance of an OCS under various icing conditions.First,a dynamic model considering icing conditions is constructed to simulate the interaction within the PCS.Five different OCS structures with various icing thicknesses are studied.The parameters of the contact force within the PCS and proportion of high-possibility arcing moments are obtained.The dependence of the contact force on the icing thickness and pantograph displacement has been illustrated in the form of cloud maps.Finally,the OCS sensitivity coefficient is calculated,and ice-covered environmental adaptability assessments for the five different OCS structures are compared.展开更多
Aims:To explore the point-wise correlations between 10-2 visual field(VF)metrics and macular vessel density,as measured by optical coherence tomography angiography(OCTA),in patients with early open-angle glaucoma(OAG)...Aims:To explore the point-wise correlations between 10-2 visual field(VF)metrics and macular vessel density,as measured by optical coherence tomography angiography(OCTA),in patients with early open-angle glaucoma(OAG)and healthy controls.Methods:This is a cross-sectional study that retrospectively analyzed data from 54 participants(18 early OAG patients and 36 healthy controls)from the Zhongshan Ophthalmic Center.All participants underwent comprehensive ophthalmic examinations,10-2 VF,and macular OCTA imaging.The correlation between capillary density(CD)in macular subregions and light sensitivity(LS)at corresponding VF test points was analyzed using Pearson's correlation coefficients.Results:The analysis revealed a significant reduction in CD within the inferior macular regions of glaucomatous eyes.Notably,there were strong point-wise correlations between CD and 10-2 VF,particularly in the inferior region of outer ring(peak r=0.534,P<0.001).Conclusion:The point-wise correlation between 10-2 VF and macular CD demonstrates the potential for using CD to predict central VF damage in glaucoma,emphasizing the importance of macular microcirculation in early disease screening.展开更多
The pantograph-catenary arc has persistently posed a challenge,impeding the advancement of high-speed rail systems.As the velocity of high-speed trains continues to escalate and environmental conditions become increas...The pantograph-catenary arc has persistently posed a challenge,impeding the advancement of high-speed rail systems.As the velocity of high-speed trains continues to escalate and environmental conditions become increasingly complex,the phenomenon of pantograph-catenary arc drifting has intensified,thereby jeopardizing the safe operation of trains.To enhance the stability of the pantograph-catenary arc,this paper proposes a method to regulate arc using an AC transverse magnetic field(ATMF)and investigates the regulation law of ATMF on an arc in airflow environment.The results indicate that ATMF can effectively maintain arc stability,with the stability enhancing as the magnetic field frequency increases up to a threshold value.In an airflow environment,the stabilization effect is maximized at a frequency of 50 Hz,with arc voltage fluctuation at 4.65 V,accounting for only 5.47%of total arc voltage.It is also found that the arc temperature increases with the frequency of the magnetic field,reaching 4743 K at 10 Hz and 4976 K at 1000 Hz.In addition,the effects of sinusoidal,triangular and rectangular magnetic field excitation currents on the arc are investigated,and it is found that the arc shows the greatest stability in the triangular field,with a voltage fluctuation of 3.04 V.This study provides theoretical support for the application of ATMF regulation to enhance the stability of the pantograph-catenary arc.展开更多
The high-affinity K＋ （HAK） transporter gene family is the largest family in plant that functions as potassium transporter and is important for various aspects of plant life. In the present study, we identified 27 m...The high-affinity K＋ （HAK） transporter gene family is the largest family in plant that functions as potassium transporter and is important for various aspects of plant life. In the present study, we identified 27 members of this family in rice genome. The phylogenetic tree divided the land plant HAK transporter proteins into 6 distinct groups. Although the main characteristic of this family was established before the origin of seed plants, they also showed some differences between the members of non-seed and seed plants. The HAK genes in rice were found to have expanded in lineage-specific manner after the split of monocots and dicots, and both segmental duplication events and tandem duplication events contributed to the expansion of this family. Functional divergence analysis for this family provided statistical evidence for shifted evolutionary rate after gene duplication. Further analysis indicated that both point mutant with positive selection and gene conversion events contributed to the evolution of this family in rice.展开更多
基金supported by the Seed Industry Revitalization Project of Jiangsu Province,China(JBGS[2021]009)the National Natural Science Foundation of China(32061143030 and 31972487)+3 种基金the Jiangsu Province University Basic Science Research Project,China(21KJA210002)the Key Research and Development Program of Jiangsu Province,China(BE2022343)the Innovative Research Team of Universities in Jiangsu Province,China,the High-end Talent Project of Yangzhou University,China,the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),Chinathe Qing Lan Project of Jiangsu Province,China。
文摘Nitrogen(N), phosphorus(P), and potassium(K) are essential macronutrients that are crucial not only for maize growth and development, but also for crop yield and quality. The genetic basis of macronutrient dynamics and accumulation during grain filling in maize remains largely unknown. In this study, we evaluated grain N, P, and K concentrations in 206 recombinant inbred lines generated from a cross of DH1M and T877 at six time points after pollination. We then calculated conditional phenotypic values at different time intervals to explore the dynamic characteristics of the N, P, and K concentrations. Abundant phenotypic variations were observed in the concentrations and net changes of these nutrients. Unconditional quantitative trait locus(QTL) mapping revealed 41 non-redundant QTLs, including 17, 16, and 14 for the N, P, and K concentrations, respectively. Conditional QTL mapping uncovered 39 non-redundant QTLs related to net changes in the N, P, and K concentrations. By combining QTL, gene expression, co-expression analysis, and comparative genomic data, we identified 44, 36, and 44 candidate genes for the N, P, and K concentrations, respectively, including GRMZM2G371058 encoding a Doftype zinc finger DNA-binding family protein, which was associated with the N concentration, and GRMZM2G113967encoding a CBL-interacting protein kinase, which was related to the K concentration. The results deepen our understanding of the genetic factors controlling N, P, and K accumulation during maize grain development and provide valuable genes for the genetic improvement of nutrient concentrations in maize.
基金supported by the National Natural Science Foundation of China(32100448,32070558,32061143030,32170636)Natural Science Foundation of Jiangsu Province(BK20210799)+2 种基金Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),the Seed Industry Revitalization Project of Jiangsu Province(JBGS[2021]009)the Shanghai Science and Technology Agriculture Project([2022]No.1–6)the Project of Zhongshan Biological Breeding Laboratory(BM2022008-029)。
文摘In a study of DNA methylation changes in melatonin-deficient rice mutants,mutant plants showed premature leaf senescence during grain-filling and reduced grain yield.Melatonin deficiency led to transcriptional reprogramming,especially of genes involved in chlorophyll and carbon metabolism,redox regulation,and transcriptional regulation,during dark-induced leaf senescence.Hypomethylation of mCG and mCHG in the melatonin-deficient rice mutants was associated with the expression change of both protein-coding genes and transposable element-related genes.Changes in gene expression and DNA methylation in the melatonin-deficient mutants were compensated by exogenous application of melatonin.A decreased S-adenosyl-L-methionine level may have contributed to the DNA methylation variations in rice mutants of melatonin deficiency under dark conditions.
基金supported by the Key Research and Development Program of Jiangsu Province(BE2022343)the Seed Industry Revitalization Project of Jiangsu Province(JBGS[2021]009)+2 种基金the National Natural Science Foundation of China(32061143030 and 31972487)Jiangsu Province University Basic Science Research Project(21KJA210002)the Innovative Research Team of Universities in Jiangsu Province,the High-End Talent Project of Yangzhou University,the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),and Qing Lan Project of Jiangsu Province.
文摘The nutritional composition and overall quality of maize kernels are largely determined by the key chemical com-ponents:protein,oil,and starch.Nevertheless,the genetic basis underlying these nutritional quality traits during grainfilling remains poorly understood.In this study,the concentrations of protein,oil,and starch were studied in 204 recombinant inbred lines resulting from a cross between DH1M and T877 at four different stages post-pollination.All the traits exhibited considerable phenotypic variation.During the grain-filling stage,the levels of protein and starch content generally increased,whereas oil content decreased,with significant changes observed between 30 and 40 days after pollination.Quantitative trait locus(QTL)mapping was conducted and a total of 32 QTLs,comprising 14,12,and 6 QTLs for grain protein,oil,and starch content were detected,respectively.Few QTLs were consistently detectable across different time points.By integrating QTL analysis,glo-bal gene expression profiling,and comparative genomics,we identified 157,86,and 54 differentially expressed genes harboring nonsynonymous substitutions between the parental lines for grain protein,oil,and starch con-tent,respectively.Subsequent gene function annotation prioritized 15 candidate genes potentially involved in reg-ulating grain quality traits,including those encoding transcription factors(NAC,MADS-box,bZIP,and MYB),cell wall invertase,cellulose-synthase-like protein,cell division cycle protein,trehalase,auxin-responsive factor,and phloem protein 2-A13.Our study offers significant insights into the genetic architecture of maize kernel nutritional quality and identifies promising QTLs and candidate genes,which are crucial for the genetic enhance-ment of these traits in maize breeding programs.
基金supported by the National Natural Science Foundation of China(31801028,32061143030,and 41801013)the National Key Technology Research and Development Program of China(2016YFD0100303)+2 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Innovative Research Team of Ministry of Agriculturethe Qing-Lan Project of Yangzhou University。
文摘Rice(Oryza sativa)provides a staple food source for more than half the world population.However,the current pace of rice breeding in yield growth is insufficient to meet the food demand of the everincreasing global population.Genomic selection(GS)holds a great potential to accelerate breeding progress and is cost-effective via early selection before phenotypes are measured.Previous simulation and experimental studies have demonstrated the usefulness of GS in rice breeding.However,several affecting factors and limitations require careful consideration when performing GS.In this review,we summarize the major genetics and statistical factors affecting predictive performance as well as current progress in the application of GS to rice breeding.We also highlight effective strategies to increase the predictive ability of various models,including GS models incorporating functional markers,genotype by environment interactions,multiple traits,selection index,and multiple omic data.Finally,we envision that integrating GS with other advanced breeding technologies such as unmanned aerial vehicles and open-source breeding platforms will further improve the efficiency and reduce the cost of breeding.
基金supported by the Priority Academic Program Development of Jiangsu Higher Education Institutionthe National Natural Science Foundation of China(Nos.91535103,31391632,and 31200943)+4 种基金the National High Technology Research and Development Program of China(No.2014AA10A601-5)the Natural Science Foundation of Jiangsu Province(No.BK2012261)the Natural Science Foundation of Jiangsu Higher Education Institution(No.14KJA210005)the Postgraduate Research and Innovation Project in Jiangsu Province(No.KYLX151368)the Innovative Research Team of University in Jiangsu Province
文摘Dissecting the genetic architecture of complex traits is an ongoing challenge for geneticists.Two complementary approaches for genetic mapping,linkage mapping and association mapping have led to successful dissection of complex traits in many crop species.Both of these methods detect quantitative trait loci(QTL) by identifying marker–trait associations,and the only fundamental difference between them is that between mapping populations,which directly determine mapping resolution and power.Based on this difference,we first summarize in this review the advances and limitations of family-based mapping and natural population-based mapping instead of linkage mapping and association mapping.We then describe statistical methods used for improving detection power and computational speed and outline emerging areas such as large-scale meta-analysis for genetic mapping in crops.In the era of next-generation sequencing,there has arisen an urgent need for proper population design,advanced statistical strategies,and precision phenotyping to fully exploit high-throughput genotyping.
基金supported by grants from the National Program on the Development of Basic Research (2011CB100100)the Priority Academic Program Development of Jiangsu Higher Education Institutions, the National Natural Science Foundations (31391632, 31200943, 31171187, and 91535103)+3 种基金the National High-tech R&D Program (863 Program) (2014AA10A601-5)the Natural Science Foundations of Jiangsu Province (BK20150010)the Natural Science Foundation of the Jiangsu Higher Education Institutions (14KJA210005)the Innovative Research Team of Universities in Jiangsu Province (KYLX_1352)
文摘Many complex traits are highly correlated rather than independent. By taking the correlation structure of multiple traits into account, joint association analyses can achieve both higher statistical power and more accurate estimation. To develop a statistical approach to joint association analysis that includes allele detection and genetic effect estimation, we combined multivariate partial least squares regression with variable selection strategies and selected the optimal model using the Bayesian Information Criterion(BIC). We then performed extensive simulations under varying heritabilities and sample sizes to compare the performance achieved using our method with those obtained by single-trait multilocus methods. Joint association analysis has measurable advantages over single-trait methods, as it exhibits superior gene detection power, especially for pleiotropic genes. Sample size, heritability,polymorphic information content(PIC), and magnitude of gene effects influence the statistical power, accuracy and precision of effect estimation by the joint association analysis.
基金supported by the National Natural Science Foundation of China(31972487,31902101,32172009 and 32061143030)the Innovative Research Team of Universities in Jiangsu Province,the Science and Technology Development Plan Project of Henan Province(212102110152)+1 种基金the High-end Talent Project of Yangzhou Universitythe Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Stalk strength increases resistance to stalk lodging,which causes maize(Zea mays L.)production losses worldwide.The genetic mechanisms regulating stalk strength remain unclear.In this study,three stalk strength-related traits(rind penetrometer resistance,stalk crushing strength,and stalk bending strength)and four plant architecture traits(plant height,ear height,stem diameter,stem length)were measured in three field trials.Substantial phenotypic variation was detected for these traits.A genome-wide association study(GWAS)was conducted using general and mixed linear models and 372,331 single-nucleotide polymorphisms(SNPs).A total of 94 quantitative trait loci including 241 SNPs were detected.By combining the GWAS data with public gene expression data,56 candidate genes within 50 kb of the significant SNPs were identified,including genes encoding flavonol synthase(GRMZM2G069298,ZmFLS2),nitrate reductase(GRMZM5G878558,ZmNR2),glucose-1-phosphate adenylyltransferase(GRMZM2G027955),and laccase(GRMZM2G447271).Resequencing GRMZM2G069298 and GRMZM5G878558 in all tested lines revealed respectively 47 and 2 variants associated with RPR.Comparison of the RPR of the zmnr2EMS mutant and the wild-type plant under high-and low-nitrogen conditions verified the GRMZM5G878558 function.These findings may be useful for clarifying the genetic basis of stalk strength.The identified candidate genes and variants may be useful for the genetic improvement of maize lodging resistance.
基金supported by grants from the National Natural Science Foundation of China(32061143030,32170636,32100448)the Key Research and Development Program of Jiangsu Province(BE2022343)+6 种基金the Seed Industry Revitalization Project of Jiangsu Province(JBGS[2021]009)Project of Hainan Yazhou Bay Seed Lab(B21HJ0223)the State Key Laboratory of North China Crop Improvement and Regulation(NCCIR2021KF-5,NCCIR2021ZZ-4)Jiangsu Province Agricultural Science and Technology Independent Innovation(CX(21)1003)the Independent Scientific Research Project of the Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding(PLR202102)the Open Funds of the Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding(PL202005)Yangzhou University High-end Talent Support Program,and the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘Genomic selection(GS)is a powerful tool for improving genetic gain in maize breeding.However,its routine application in large-scale breeding pipelines is limited by the high cost of genotyping platforms.Although sequencing-based and array-based genotyping platforms have been used for GS,few studies have compared prediction performance among platforms.In this study,we evaluated the predictabilities of four agronomic traits in 305 maize hybrids derived from 149 parental lines subjected to genotyping by sequencing(GBS),a 40K SNP array,and target sequence capture(TSC)using eight GS models.The GBS marker dataset yielded the highest predictabilities for all traits,followed by TSC and SNP array datasets.We investigated the effect of marker density and statistical models on predictability among genotyping platforms and found that 1K SNPs were sufficient to achieve comparable predictabilities to 10K and all SNPs,and BayesB,GBLUP,and RKHS performed well,while XGBoost performed poorly in most cases.We also selected significant SNP subsets using genome-wide association study(GWAS)analyses in three panels to predict hybrid performance.GWAS facilitated selecting effective SNP subsets for GS and thus reduced genotyping cost,but depended heavily on the GWAS panel.We conclude that there is still room for optimization of the existing SNP array,and using genotyping by target sequencing(GBTS)techniques to integrate a few functional markers identified by GWAS into the 1K SNP array holds great promise of being an effective strategy for developing desirable GS breeding arrays.
基金supported by grants from the National Natural Science Foundation of China(31801028,41801013,31902101)the National Key Research and Development Program of China(2016YFD0100303)+2 种基金Natural Science Foundation of Jiangsu Province(BK20180939)Qing Lan Project of Yangzhou Universitythe Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘As the end products of cellular regulatory processes,metabolites provide the link between genotypes and phenotypes.Althoughmetabolites have been widely applied for functional gene detection and phenotype prediction in maize,there is little research focusing on the genetic information of metabolites per se.Here,we performed genetic analyses for the kernel metabolites of 11 parental inbred lines of six representative maize varieties,including Zhongdan 2,Danyu 13,Yedan 13,Zhengdan 958,Xianyu 355,and Suyu 16,as well as their 26 reciprocal hybrids.We identified a total of 208 metabolites in maize kernels using untargeted metabolite profiling technology.Both cluster analysis and principal component analysis indicated that kernel metabolites could distinguish hybrids from their parents.Analysis of variance further revealed that 163 metabolites exhibited significant differences between parents and hybrids,and 40 metabolites showed significant differences between reciprocal crosses.We also investigated the genetic effects and heterosis for each metabolite.By taking all hybrids into consideration,about two-thirds of all metabolites displayed overdominant with 36.8%and 31%of them displaying positive overdominant and negative overdominant,respectively.Besides,27.5%and 20.4%of all hybrid combinations showed significant mid-parent heterosis and over-parent heterosis,respectively.Our findings revealed that kernel metabolites exhibited the diversity of relationship between maize hybrids and their parental lines.Additionally,we identified 25 significant metabolicmarkers related to 11 agronomic traits using the LASSO method.Seven metabolic markers were associated with more than one trait simultaneously.These results provide a genetic basis for further utilization of metabolites in the genetic improvement of maize.
基金supported by National Natural Science Foundation of China(Nos.U19A20105 and 52077182)。
文摘The relative motion of the electrodes is a typical feature of sliding electrical contact systems.The system fault caused by the arc is the key problem that restricts the service life of the sliding electrical contact system.In this paper,an arcing experimental platform that can accurately control the relative speed and distance of electrodes is built,and the influence of different electrode speeds and electrode distances on arc motion characteristics is explored.It is found that there are three different modes of arc root motion:single arc root motion mode,single and double arc roots alternating motion mode,and multiple arc roots motion mode.The physical process and influence mechanism of different arc root motion modes are further studied,and the corresponding relationship between arc root motion modes and electrode speed is revealed.In addition,to further explore the distribution characteristics of arc temperature and its influencing factors,an arc magnetohydrodynamic model under the relative motion of electrodes is established,and the variation law of arc temperature under the effect of different electrode speeds and electrode distances is summarized.Finally,the influence mechanism of electrode speed and electrode distance on arc temperature,arc root distance,and arc root speed is clarified.The research results enrich the research system of arc dynamic characteristics in the field of sliding electrical contact,and provide theoretical support for restraining arc erosion and improving the service life of the sliding electrical contact system.
基金supported by the National Key Research and Development Program of China(2016YFD0100303)the National Natural Science Foundation of China(31972487,31601810,and 31902101)+1 种基金the Natural Science Foundation of Jiangsu Province(BK20180920)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Crown root traits,including crown root angle(CRA),diameter(CRD),and number(CRN),are major determining factors of root system architecture,which influences crop production.In maize,the genetic mechanisms determining crown root traits in the field are largely unknown.CRA,CRD,and CRN were evaluated in a recombinant inbred line population in three field trials.High phenotypic variation was observed for crown root traits,and all measured traits showed significant genotype–environment interactions.Singleenvironment(SEA)and multi-environment(MEA)quantitative trait locus(QTL)analyses were conducted for CRA,CRD,and CRN.Of 46 QTL detected by SEA,most explained less than 10%of the phenotypic variation,indicating that a large number of minor-effect QTL contributed to the genetic component of these traits.MEA detected 25 QTL associated with CRA,CRD,and CRN,and 2 and 1 QTL were identified with significant QTL-by-environment interaction effects for CRA and CRD,respectively.A total of 26.1%(12/46)of the QTL identified by SEA were also detected by MEA,with many being detected in more than one environment.These findings contribute to our understanding of the phenotypic and genotypic patterns of crown root traits in different environments.The identified environment-specific QTL and stable QTL may be used to improve root traits in maize breeding.
基金funded by the National Basic Research Program of China (2013CB127803, 2011CB109304)National High Technology Research and Development Program of China (2013AA102602)+2 种基金National Natural Science Foundation of China (31371662, 31461143022)China Agriculture Research System (CARS-14)Shandong Agricultural Industrialization Project for New Variety Development (2014–2016)
文摘Simple sequence repeats(SSRs) are important molecular markers for assessing genetic diversity in Arachis hypogaea L. and many other crops and constructing genetic linkage maps for important agricultural traits. In this study, 29,357 potential SSRs were identified in 22,806 unigenes assembled from A. hypogaea transcript sequences. Of these unigenes, 1883 and 4103 were annotated and assigned in Kyoto Encyclopedia of Genes and Genomes Orthology and Eukaryotic Orthologous Groups databases, respectively. Among the SSR motifs, mono-(19,065; 64.94%) and trinucleotide(5033; 17.14%) repeats were the most common, and the three most dominant motifs were A/T(18,358; 62.54%), AG/CT(2804;9.55%), and AAG/CTT(1396; 4.76%). Polymerase chain reaction(PCR) primer pairs were designed for 4340 novel SSR markers and 210 new SSRs were validated using 24 A. hypogaea varieties. Of the 210, 191(91%) yielded PCR products, with 37(18%) identifying polymorphisms. The 37 polymorphic SSR markers detected 146 alleles(2–10 alleles per locus), and the average polymorphic information content was 0.403(with a range of 0.077 to0.819). The new SSRs enrich the current marker resources for A. hypogaea and may also be useful for genetic diversity analysis, functional genomics research, and molecular breeding.
基金the National Key Research and Development Program of China(2016YFD0100303)the National High Technology Research and Development Program of China(2014AA10A601-5)+4 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions,the National Natural Science Foundation of China(91535103,31371632,31200943)the Natural Science Foundation of Jiangsu Province(BK20150010)the Scientific and Technological Project of Jiangsu Province,China(BE2018325)the Innovative Research Team of Ministry of Agriculturethe Qing Lan Project of Jiangsu Province.
文摘Seed moisture at harvest is a critical trait affecting maize quality and mechanized production,and is directly determined by the dehydration process after physiological maturity.However,the dynamic nature of seed dehydration leads to inaccurate evaluation of the dehydration process by conventional determination methods.Seed dry weight and fresh weight were recorded at 14 time points after pollination in a recombinant inbred line(RIL)population derived from two inbred lines with contrasting seed dehydration dynamics.The dehydration curves of RILs were determined by fitting trajectories of dry weight accumulation and dry weight/fresh weight ratio change based on a logistic model,allowing the estimation of eight characteristic parameters that can be used to describe dehydration features.Quantitative trait locus(QTL)mapping,taking these parameters as traits,was performed using multiple methods.Single-trait QTL mapping revealed 76 QTL associated with dehydration characteristic parameters,of which the phenotypic variation explained(PVE)was 1.03%to 15.24%.Multipleenvironment QTL analysis revealed 21 related QTL with PVE ranging from 4.23%to 11.83%.Multiple-trait QTL analysis revealed 58 QTL,including 51 pleiotropic QTL.Combining these mapping results revealed 12 co-located QTL and the dehydration process of RILs was divided into three patterns with clear differences in dehydration features.These results not only deepen general understanding of the genetic characteristics of seed dehydration but also suggest that this approach can efficiently identify associated genetic loci in maize.
基金supported by National Natural Science Foundation of China(No.U1966602)the Excellent Young Scientists Fund of China(No.51922090).
文摘For high-voltage direct current(HVDC)power grid transmission with higher voltages,the energyconsuming branch of the DC circuit breaker is required to dissipate huge energies of more than megajoules in a short time in the case of a fault and short circuit.The requirements for huge volume and weight are difficult to meet with energy-consuming equipment based on ZnO.In this paper,a new energy consumption method is proposed based on gallium indium tin(GaInSn)liquid metal in the arcing process,and a test platform with adjustable short-circuit current is built.The mechanism triggering GaInSn liquid metal arcing energy consumption is studied.It is found that short-circuit current and channel aperture are the key parameters affecting the energy consumption of liquid metal arcing.The characteristics of GaInSn liquid metal energy consumption are investigated,and four stages of liquid metal energy consumption are found:oscillatory shrinkage,arc breakdown,arc burning phase change and arc extinction.The influence of short-circuit current and channel aperture on the energy consumption characteristics of GaInSn liquid metal is investigated.To further explore the physical mechanism of the above phenomena,a magneto-hydrodynamic model of energy consumption in the GaInSn liquid metal arcing process is established.The influence of short-circuit current and channel aperture on the temperature distribution of the liquid metal arc is analyzed.The mechanism of the effect of short-circuit current and channel aperture on peak arc temperature and the temperature diffusion rate is clarified.The research results provide theoretical support for this new liquid metal energy consumption mode DC circuit breaker.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51707166,51922090,U1966602,and U19A20105)the Sichuan Science and Technology General Project(Grant Nos.2019YJ0213 and2019JDJQ0019)。
文摘The fault caused by a pantograph-catenary arc is the main factor that threatens the stability of high-speed railway energy transmission.Pantograph-catenary arc vertical drift is more severe than the case under normal pressure,as it is easy to develop the rigid busbar,which may lead to the flashover occurring around the support insulators.We establish a pantograph-catenary arc experiment and diagnosis platform to simulate low pressure and strong airflow environment.Meanwhile,the variation law of arc drift height with time under different air pressures and airflow velocities is analyzed.Moreover,arc drift characteristics and influencing factors are explored.The physical process of the arc column drifting to the rigid busbar with the jumping mechanism of the arc root on the rigid busbar is summarized.In order to further explore the mechanism of the above physical process,a multi-field stress coupling model is built,as the multi-stress variation law of arc is quantitatively evaluated.The dynamic action mechanism of multi-field stress on arc drifting characteristics is explored,as the physical mechanism of arc drifting under low pressure is theoretically explained.The research results provide theoretical support for arc suppression in high-altitude areas.
文摘(Molecular Plant 16,1832-1846,November 62023)The originally published version of this manuscript contained several small mistakes in the labels and legends of main and supplemental figures,along with a few small mistakes in the main text,that have now been corrected.Specifically,in Figure 6G,the label“NILGY31^(Pijx)”has been corrected to“NIL^(Pijx)”,and in the legend of Figure 6H,“PPL^(Pijx Piz-t)”and“PPL^(Pijx Pigm)”have been corrected to“NIL^(Piz-t Pijx)”and“PPL^(Pigm Pijx).”In Figure S8A。
基金China State Railway Group Co.,Ltd.(L2022G006)Chengdu Guojia Electrical Engineering Co.,Ltd.(NEEC-2022-A04)Natural Science Foundation of Sichuan Province(2022NSFSC1863).
文摘High-speed trains rely on pantograph-catenary systems(PCSs)to collect electrical energy from power systems.However,the dynamic interaction between the pantograph and the catenary system may become mismatched once ice accumulates on the overhead conductors.More frequent arcing may occur within the PCS during train operation,posing an unpredictable threat to operational safety.Therefore,it is crucial to evaluate the ability of overhead contact system(OCS)to withstand ice-covered variability during line desgin.A new strategy is proposed to evaluate the adaptive performance of an OCS under various icing conditions.First,a dynamic model considering icing conditions is constructed to simulate the interaction within the PCS.Five different OCS structures with various icing thicknesses are studied.The parameters of the contact force within the PCS and proportion of high-possibility arcing moments are obtained.The dependence of the contact force on the icing thickness and pantograph displacement has been illustrated in the form of cloud maps.Finally,the OCS sensitivity coefficient is calculated,and ice-covered environmental adaptability assessments for the five different OCS structures are compared.
基金supported by the National Key Research and Development Program of China(2022YFC2502800)the National Natural Science Foundation of China(82070955)the Science and Technology Program of Guangzhou,China(2024A03J0250).
文摘Aims:To explore the point-wise correlations between 10-2 visual field(VF)metrics and macular vessel density,as measured by optical coherence tomography angiography(OCTA),in patients with early open-angle glaucoma(OAG)and healthy controls.Methods:This is a cross-sectional study that retrospectively analyzed data from 54 participants(18 early OAG patients and 36 healthy controls)from the Zhongshan Ophthalmic Center.All participants underwent comprehensive ophthalmic examinations,10-2 VF,and macular OCTA imaging.The correlation between capillary density(CD)in macular subregions and light sensitivity(LS)at corresponding VF test points was analyzed using Pearson's correlation coefficients.Results:The analysis revealed a significant reduction in CD within the inferior macular regions of glaucomatous eyes.Notably,there were strong point-wise correlations between CD and 10-2 VF,particularly in the inferior region of outer ring(peak r=0.534,P<0.001).Conclusion:The point-wise correlation between 10-2 VF and macular CD demonstrates the potential for using CD to predict central VF damage in glaucoma,emphasizing the importance of macular microcirculation in early disease screening.
基金supported by National Natural Science Foundation of China (Nos.52322704 and 52077182)。
文摘The pantograph-catenary arc has persistently posed a challenge,impeding the advancement of high-speed rail systems.As the velocity of high-speed trains continues to escalate and environmental conditions become increasingly complex,the phenomenon of pantograph-catenary arc drifting has intensified,thereby jeopardizing the safe operation of trains.To enhance the stability of the pantograph-catenary arc,this paper proposes a method to regulate arc using an AC transverse magnetic field(ATMF)and investigates the regulation law of ATMF on an arc in airflow environment.The results indicate that ATMF can effectively maintain arc stability,with the stability enhancing as the magnetic field frequency increases up to a threshold value.In an airflow environment,the stabilization effect is maximized at a frequency of 50 Hz,with arc voltage fluctuation at 4.65 V,accounting for only 5.47%of total arc voltage.It is also found that the arc temperature increases with the frequency of the magnetic field,reaching 4743 K at 10 Hz and 4976 K at 1000 Hz.In addition,the effects of sinusoidal,triangular and rectangular magnetic field excitation currents on the arc are investigated,and it is found that the arc shows the greatest stability in the triangular field,with a voltage fluctuation of 3.04 V.This study provides theoretical support for the application of ATMF regulation to enhance the stability of the pantograph-catenary arc.
基金supported by the National Basic Research Program of China (No. 2006CB101700)the National High- tech Research and Development Program (No. 2006AA10Z165)the Program for New Century Excellent Talents in Uni-versity of China (No. NCET2005-05- 0502).
文摘The high-affinity K＋ （HAK） transporter gene family is the largest family in plant that functions as potassium transporter and is important for various aspects of plant life. In the present study, we identified 27 members of this family in rice genome. The phylogenetic tree divided the land plant HAK transporter proteins into 6 distinct groups. Although the main characteristic of this family was established before the origin of seed plants, they also showed some differences between the members of non-seed and seed plants. The HAK genes in rice were found to have expanded in lineage-specific manner after the split of monocots and dicots, and both segmental duplication events and tandem duplication events contributed to the expansion of this family. Functional divergence analysis for this family provided statistical evidence for shifted evolutionary rate after gene duplication. Further analysis indicated that both point mutant with positive selection and gene conversion events contributed to the evolution of this family in rice.
