A complete reference genome assembly is crucial for biological research and genetic improvement. Owing to its large size and highly repetitive nature, there are numerous gaps in the globally used wheat Chinese Spring ...A complete reference genome assembly is crucial for biological research and genetic improvement. Owing to its large size and highly repetitive nature, there are numerous gaps in the globally used wheat Chinese Spring (CS) genome assembly. In this study, we generated a 14.46 Gb near-complete assembly of the CS genome, with a contig N50 of over 266 Mb and an overall base accuracy of 99.9963%. Among the 290 gaps that remained (26, 257, and 7 gaps from the A, B, and D subgenomes, respectively), 278 were extremely high-copy tandem repeats, whereas the remaining 12 were transposable-element-associated gaps. Four chromosome assemblies were completely gap-free, including chr1D, chr3D, chr4D, and chr5D. Extensive annotation of the near-complete genome revealed 151 405 high-confidence genes, of which 59 180 were newly annotated, including 7602 newly assembled genes. Except for the centromere of chr1B, which has a gap associated with superlong GAA repeat arrays, the centromeric sequences of all of the remaining 20 chromosomes were completely assembled. Our near-complete assembly revealed that the extent of tandem repeats, such as simple-sequence repeats, was highly uneven among different subgenomes. Similarly, the repeat compositions of the centromeres also varied among the three subgenomes. With the genome sequences of all six types of seed storage proteins (SSPs) fully assembled, the expression of ω-gliadin was found to be contributed entirely by the B subgenome, whereas the expression of the other five types of SSPs was most abundant from the D subgenome. The near-complete CS genome will serve as a valuable resource for genomic and functional genomic research and breeding of wheat as well as its related species.展开更多
This paper analyzes and studies the factors affecting the service life of the damping body in the assembly and use of the damping body of rod and wire mill, and puts forward the corresponding preventive measures to pr...This paper analyzes and studies the factors affecting the service life of the damping body in the assembly and use of the damping body of rod and wire mill, and puts forward the corresponding preventive measures to prolong the service life of the damping body;At the same time, according to the working characteristics of different sorties of rolling mill, the disc spring is introduced for corresponding replacement, the requirements of material type range and roll diameter range between different sorties in rod and wire production workshop are analyzed, and according to the size characteristics of mechanism of different types of short stress rolling mill.The application range of the number of disc springs corresponding to the changes of material shape and roll diameter of different types of short stress rolling mills is optimized.The practice shows that the stability of rolling mill is effectively guaranteed, the service life of damping body and disc spring is prolonged, and the negative difference stability of deformed steel bar is improved.展开更多
基金supported by the National Key Research and Development Program of China(2023YFF1000100)the National Natural Science Foundation of China(31991210,31921005,32020103004,and 32225038)+2 种基金the Pinduoduo-China Agricultural University Research Fund(PC2023A01004)the New Cornerstone Investigation Program(NCI202234)the 2115 Talent Development Program of China Agricultural University.
文摘A complete reference genome assembly is crucial for biological research and genetic improvement. Owing to its large size and highly repetitive nature, there are numerous gaps in the globally used wheat Chinese Spring (CS) genome assembly. In this study, we generated a 14.46 Gb near-complete assembly of the CS genome, with a contig N50 of over 266 Mb and an overall base accuracy of 99.9963%. Among the 290 gaps that remained (26, 257, and 7 gaps from the A, B, and D subgenomes, respectively), 278 were extremely high-copy tandem repeats, whereas the remaining 12 were transposable-element-associated gaps. Four chromosome assemblies were completely gap-free, including chr1D, chr3D, chr4D, and chr5D. Extensive annotation of the near-complete genome revealed 151 405 high-confidence genes, of which 59 180 were newly annotated, including 7602 newly assembled genes. Except for the centromere of chr1B, which has a gap associated with superlong GAA repeat arrays, the centromeric sequences of all of the remaining 20 chromosomes were completely assembled. Our near-complete assembly revealed that the extent of tandem repeats, such as simple-sequence repeats, was highly uneven among different subgenomes. Similarly, the repeat compositions of the centromeres also varied among the three subgenomes. With the genome sequences of all six types of seed storage proteins (SSPs) fully assembled, the expression of ω-gliadin was found to be contributed entirely by the B subgenome, whereas the expression of the other five types of SSPs was most abundant from the D subgenome. The near-complete CS genome will serve as a valuable resource for genomic and functional genomic research and breeding of wheat as well as its related species.
文摘This paper analyzes and studies the factors affecting the service life of the damping body in the assembly and use of the damping body of rod and wire mill, and puts forward the corresponding preventive measures to prolong the service life of the damping body;At the same time, according to the working characteristics of different sorties of rolling mill, the disc spring is introduced for corresponding replacement, the requirements of material type range and roll diameter range between different sorties in rod and wire production workshop are analyzed, and according to the size characteristics of mechanism of different types of short stress rolling mill.The application range of the number of disc springs corresponding to the changes of material shape and roll diameter of different types of short stress rolling mills is optimized.The practice shows that the stability of rolling mill is effectively guaranteed, the service life of damping body and disc spring is prolonged, and the negative difference stability of deformed steel bar is improved.
