Brassica rapa comprises several important cultivated vegetables and oil crops.Current reference genome assemblies of Brassica rapa are quite fragmented and not highly contiguous,thereby limiting extensive genetic and ...Brassica rapa comprises several important cultivated vegetables and oil crops.Current reference genome assemblies of Brassica rapa are quite fragmented and not highly contiguous,thereby limiting extensive genetic and genomic analyses.Here,we report an improved assembly of the B.rapa genome(v3.0)using single-molecule sequencing,optical mapping,and chromosome conformation capture technologies(Hi-C).Relative to the previous reference genomes,our assembly features a contig N50 size of 1.45 Mb,representing a~30-fold improvement.We also identified a new event that occurred in the B.rapa genome~1.2 million years ago,when a long terminal repeat retrotransposon(LTR-RT)expanded.Further analysis refined the relationship of genome blocks and accurately located the centromeres in the B.rapa genome.The B.rapa genome v3.0 will serve as an important community resource for future genetic and genomic studies in B.rapa.This resource will facilitate breeding efforts in B.rapa,as well as comparative genomic analysis with other Brassica species.展开更多
Solanum lycopersicum var.cerasiforme accession PI 114490 has broad-spectrum resistance to bacterial spot caused by several species of Xanthomonas.Resistance is quantitatively inherited,and a common quantitative trait ...Solanum lycopersicum var.cerasiforme accession PI 114490 has broad-spectrum resistance to bacterial spot caused by several species of Xanthomonas.Resistance is quantitatively inherited,and a common quantitative trait locus QTL-11B on chromosome 11 has been identified previously.In this study,the SlPub24 gene was characterized in QTL-11B.SlPub24 in PI 114490 was upregulated by infection with X.euvesicatoria pv.perforans race T3,but its transcription was low in the susceptible line OH 88119 whether or not it was infected by the pathogen.The differential expression of SlPub24 between PI 114490 and OH 88119 was due to great sequence variation in the promoter region.The promoter of SlPub24 in OH 88119 had very low activity and did not respond to pathogen infection.Transgenic lines of OH 88119 overexpressing SlPub24 isolated from PI 114490 showed significantly enhanced resistance,while mutants of Slpub24 generated by CRISPR/Cas9 editing showed more susceptibility to race T3 and to other races.The mutants also showed spontaneous cell death in leaves.The expression of the salicylic acid(SA)pathway gene phenylalanine ammonia-lyase(PAL)and signaling-related genes pathogenesis-related(PR1)and nonexpresser of PR1(NPR1)were influenced by SlPub24.The content of SA in tomato plants was consistent with the level of SlPub24 expression.Furthermore,SlPUB24 interacted with the cell wall protein SlCWP and could regulate the degradation of SlCWP.The expression levels of SlCWP and SlCWINV1,a cell wall invertase gene,showed opposite patterns during pathogen infection.The activity of SlCWINV1 was lower in mutants than in PI 114490.The results are discussed in terms of the roles of the abovementioned genes,and a potential model for SlPUB24-mediated resistance to bacterial spot is proposed.展开更多
Since the publication of this article,the authors have noticed that the total gene models(45,985),tandem arrays(2077),tandem genes(4963),redundancy removed(43,099),syntenic genes(39,858),nonsyntenic genes(3241),genes ...Since the publication of this article,the authors have noticed that the total gene models(45,985),tandem arrays(2077),tandem genes(4963),redundancy removed(43,099),syntenic genes(39,858),nonsyntenic genes(3241),genes on chromosomes(45,411),genes on scaffolds(574)of B.rapa reference genome v3.0 were mistaken in the article.展开更多
In order to improve the seedling quality of Panax notoginseng,combined with the special agronomic requirements of Panax notoginseng,a sharp angle roller soil-covering and soil-compacting device integrating the functio...In order to improve the seedling quality of Panax notoginseng,combined with the special agronomic requirements of Panax notoginseng,a sharp angle roller soil-covering and soil-compacting device integrating the functions of soil-covering and soil-compacting was designed.Based on the theoretical analysis of seed ditch conditions,soil-covering process and soilcompacting process,the structure of soil-covering and soil-compacting device was designed.Through theoretical analysis and calculation,the diameter and length of soil-covering and soil-compacting wheel were 20 cm and 10.7-14.1 cm,respectively,the sharp angle and height range were 45°-105°and 0.8-1.6 cm respectively,and the spring stiffness was 38.54 N/mm;Using the discrete element method to simulate the soil-covering and soil-compacting process,it was obtained that when the sharp angle range was 60°-90°,the sharp angle height range was 0.8-1.2 cm,and the soil-covering effect was better;Taking the forward speed,ballast pressure,sharp angle and sharp angle height of the planter as the test factors,and taking the soil-covering thickness,grain spacing and soil compactness as the indexes,the four factor and three-level Box-Behnken Design test was carried out.The response surface test analysis method was used to establish the regression equation between the factors and indexes,and determine the best parameter combination:the forward speed was 6.5 m/min,the ballast pressure was 360.5 N,the sharp angle was 67°,and the sharp angle height was 1 cm,at this time,the soil-covering thickness was 0.64 cm,the grain spacing was 5.03 cm,and the soil compactness was 321.77 kPa.According to the soil trough test,the design of soil-covering and soil-compacting device met the agronomic requirements of plant spacing,soil-compactness and soil-covering thickness during seedling sowing of Panax notoginseng.The research results can provide a reference for the design of Panax notoginseng seedling planter integrating pressing hole(ditching),sowing,soil-covering and soil-compacting.展开更多
Cratons have a long history of evolution.In this paper,applications of the magnetotelluric method used in the study of craton lithosphere over the past 30 years were reviewed,examining case studies of cratons in North...Cratons have a long history of evolution.In this paper,applications of the magnetotelluric method used in the study of craton lithosphere over the past 30 years were reviewed,examining case studies of cratons in North America,South America,Asia,Australia,and Africa.The nuclei of the Archean cratons,for example the Kalahari Craton and Rae Craton,are usually characterized by thick and highly resistive lithospheric roots.During or after the formation of the cratons,tectonothermal events,such as collision,mantle plume,and asthenosphere upwelling led to the formation of high-conductivity zones in the craton lithosphere,which could be attributed to the increased hydrogen content(of nominally anhydrous minerals),higher iron content,and formation of graphite films or sulfides along the grain boundary of minerals.These conductive zones are characterized by resistivity discontinuities in craton lithosphere.In particular,the conductive zones include(1)large-scale lithospheric mantle conductors beneath the Slave Craton,Gawler Craton,and central part of North China Craton(Trans-North China Orogen);(2)near-vertical high-conductivity zone associated with the fossil subduction zone beneath the Dharwar Craton and Slave Craton;and(3)regional lateral electrical discontinuities,such as a conductive anomaly under the Bushveld Complex of the Kaapvaal Craton.The eMoho refers to the electrical discontinuity in the crust-mantle boundary.In existing research,this has been detected under the condition of extremely high lithospheric resistivity with only a slight decrease in the lower crust,and in the case of a very thin conductive lower crust or the lack thereof.In the resistivity model,the unique"mushroom-like"lower crust-lithosphere mantle conductor and very thin lower crust layer of the North China Craton may represent lithosphere destruction and/or thinning.We also find that some of the cratons are still not well understood.Therefore,extensive three-dimensional inversion and joint interpretation of geochemical,geophysical,and geologic data are necessary to understand the tectonic evolutionary history of craton lithosphere.展开更多
基金This work is supported by the National Natural Science Foundation of China(NSFC grants 31630068 and 31722048)the National Program on Key Research Project(2016YFD0100307)+1 种基金the Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences,the Key Laboratory of Biology and Genetic Improvement of Horticultural Crops,Ministry of Agriculture,P.R.China,the Prospect of Shandong Seed Project,China(Shandong Gov.(2015)Reference No.212)the China Scholarship Council(CSC)(No.201503250081).
文摘Brassica rapa comprises several important cultivated vegetables and oil crops.Current reference genome assemblies of Brassica rapa are quite fragmented and not highly contiguous,thereby limiting extensive genetic and genomic analyses.Here,we report an improved assembly of the B.rapa genome(v3.0)using single-molecule sequencing,optical mapping,and chromosome conformation capture technologies(Hi-C).Relative to the previous reference genomes,our assembly features a contig N50 size of 1.45 Mb,representing a~30-fold improvement.We also identified a new event that occurred in the B.rapa genome~1.2 million years ago,when a long terminal repeat retrotransposon(LTR-RT)expanded.Further analysis refined the relationship of genome blocks and accurately located the centromeres in the B.rapa genome.The B.rapa genome v3.0 will serve as an important community resource for future genetic and genomic studies in B.rapa.This resource will facilitate breeding efforts in B.rapa,as well as comparative genomic analysis with other Brassica species.
基金the National Key Research and Development Program(2016YFD0101007)the Construction of Beijing Science and Technology Innovation and Service Capacity in Top Subjects(CEFF-PXM2019_014207_000032).
文摘Solanum lycopersicum var.cerasiforme accession PI 114490 has broad-spectrum resistance to bacterial spot caused by several species of Xanthomonas.Resistance is quantitatively inherited,and a common quantitative trait locus QTL-11B on chromosome 11 has been identified previously.In this study,the SlPub24 gene was characterized in QTL-11B.SlPub24 in PI 114490 was upregulated by infection with X.euvesicatoria pv.perforans race T3,but its transcription was low in the susceptible line OH 88119 whether or not it was infected by the pathogen.The differential expression of SlPub24 between PI 114490 and OH 88119 was due to great sequence variation in the promoter region.The promoter of SlPub24 in OH 88119 had very low activity and did not respond to pathogen infection.Transgenic lines of OH 88119 overexpressing SlPub24 isolated from PI 114490 showed significantly enhanced resistance,while mutants of Slpub24 generated by CRISPR/Cas9 editing showed more susceptibility to race T3 and to other races.The mutants also showed spontaneous cell death in leaves.The expression of the salicylic acid(SA)pathway gene phenylalanine ammonia-lyase(PAL)and signaling-related genes pathogenesis-related(PR1)and nonexpresser of PR1(NPR1)were influenced by SlPub24.The content of SA in tomato plants was consistent with the level of SlPub24 expression.Furthermore,SlPUB24 interacted with the cell wall protein SlCWP and could regulate the degradation of SlCWP.The expression levels of SlCWP and SlCWINV1,a cell wall invertase gene,showed opposite patterns during pathogen infection.The activity of SlCWINV1 was lower in mutants than in PI 114490.The results are discussed in terms of the roles of the abovementioned genes,and a potential model for SlPUB24-mediated resistance to bacterial spot is proposed.
文摘Since the publication of this article,the authors have noticed that the total gene models(45,985),tandem arrays(2077),tandem genes(4963),redundancy removed(43,099),syntenic genes(39,858),nonsyntenic genes(3241),genes on chromosomes(45,411),genes on scaffolds(574)of B.rapa reference genome v3.0 were mistaken in the article.
基金supported by the National Natural Science Foundation of China(Grant No.32160425)the Joint Special Key Project for Agriculture of Yunnan Science and Technology Plan(Grant No.2018FG 001-007)the Major Science and Technology Project of Yunnan Province(Grant No.202102AE090042-06-04).
文摘In order to improve the seedling quality of Panax notoginseng,combined with the special agronomic requirements of Panax notoginseng,a sharp angle roller soil-covering and soil-compacting device integrating the functions of soil-covering and soil-compacting was designed.Based on the theoretical analysis of seed ditch conditions,soil-covering process and soilcompacting process,the structure of soil-covering and soil-compacting device was designed.Through theoretical analysis and calculation,the diameter and length of soil-covering and soil-compacting wheel were 20 cm and 10.7-14.1 cm,respectively,the sharp angle and height range were 45°-105°and 0.8-1.6 cm respectively,and the spring stiffness was 38.54 N/mm;Using the discrete element method to simulate the soil-covering and soil-compacting process,it was obtained that when the sharp angle range was 60°-90°,the sharp angle height range was 0.8-1.2 cm,and the soil-covering effect was better;Taking the forward speed,ballast pressure,sharp angle and sharp angle height of the planter as the test factors,and taking the soil-covering thickness,grain spacing and soil compactness as the indexes,the four factor and three-level Box-Behnken Design test was carried out.The response surface test analysis method was used to establish the regression equation between the factors and indexes,and determine the best parameter combination:the forward speed was 6.5 m/min,the ballast pressure was 360.5 N,the sharp angle was 67°,and the sharp angle height was 1 cm,at this time,the soil-covering thickness was 0.64 cm,the grain spacing was 5.03 cm,and the soil compactness was 321.77 kPa.According to the soil trough test,the design of soil-covering and soil-compacting device met the agronomic requirements of plant spacing,soil-compactness and soil-covering thickness during seedling sowing of Panax notoginseng.The research results can provide a reference for the design of Panax notoginseng seedling planter integrating pressing hole(ditching),sowing,soil-covering and soil-compacting.
基金supported by the National Natural Science Foundation of China(Grant Nos.41630317 and 41474055)the National Key Research and Development Program of China(Grant No.2017YFC0602405)。
文摘Cratons have a long history of evolution.In this paper,applications of the magnetotelluric method used in the study of craton lithosphere over the past 30 years were reviewed,examining case studies of cratons in North America,South America,Asia,Australia,and Africa.The nuclei of the Archean cratons,for example the Kalahari Craton and Rae Craton,are usually characterized by thick and highly resistive lithospheric roots.During or after the formation of the cratons,tectonothermal events,such as collision,mantle plume,and asthenosphere upwelling led to the formation of high-conductivity zones in the craton lithosphere,which could be attributed to the increased hydrogen content(of nominally anhydrous minerals),higher iron content,and formation of graphite films or sulfides along the grain boundary of minerals.These conductive zones are characterized by resistivity discontinuities in craton lithosphere.In particular,the conductive zones include(1)large-scale lithospheric mantle conductors beneath the Slave Craton,Gawler Craton,and central part of North China Craton(Trans-North China Orogen);(2)near-vertical high-conductivity zone associated with the fossil subduction zone beneath the Dharwar Craton and Slave Craton;and(3)regional lateral electrical discontinuities,such as a conductive anomaly under the Bushveld Complex of the Kaapvaal Craton.The eMoho refers to the electrical discontinuity in the crust-mantle boundary.In existing research,this has been detected under the condition of extremely high lithospheric resistivity with only a slight decrease in the lower crust,and in the case of a very thin conductive lower crust or the lack thereof.In the resistivity model,the unique"mushroom-like"lower crust-lithosphere mantle conductor and very thin lower crust layer of the North China Craton may represent lithosphere destruction and/or thinning.We also find that some of the cratons are still not well understood.Therefore,extensive three-dimensional inversion and joint interpretation of geochemical,geophysical,and geologic data are necessary to understand the tectonic evolutionary history of craton lithosphere.
