The Asteraceae (Compositae),a large plant family of approximately 24 000-35 000 species,accounts for^10% of all angiosperm species and contributes a lot to plant diversity.The most representative members of the Astera...The Asteraceae (Compositae),a large plant family of approximately 24 000-35 000 species,accounts for^10% of all angiosperm species and contributes a lot to plant diversity.The most representative members of the Asteraceae are the economically important chrysanthemums (Chrysanthemum L.)that diversified through reticulate evolution.Biodiversity is typically created by multiple evolutionary mechanisms such as wholegenome duplication 0NGD)or polyploidization and locally repetitive genome expansion.However,the lack of genomic data from chrysanthemum species has prevented an in-depth analysis of the evolutionary mechanisms involved in their diversification.Here,we used Oxford Nanopore long-read technologyto sequence the diploid Chrysanthemum nankingense genome,which represents one of the progenitor genomes of domesticated chrysanthemums.Our analysis revealed that the evolution of the C.nankingense genome was driven by bursts of repetitive element expansion and WGD events including a recentWGD that distinguishes chrysanthemum from sunflower,which diverged from chrysanthemum approximately 38.8 million years ago.Variations of ornamental and medicinal traits in chrysanthemums are linked to the expansion of candidate gene families by duplication events including paralogous gene duplication.Collectively,our study of the assembled reference genome offers new knowledge and resources to dissect the history and pattern of evolution and diversification of chrysanthemum plants,and also to accelerate their breeding and improvement.展开更多
Targeted point mutagenesis through homologous recombination has been widely used in genetic studies and holds considerable promise for repairing disease- causing mutations in patients. However, problems such as mosaic...Targeted point mutagenesis through homologous recombination has been widely used in genetic studies and holds considerable promise for repairing disease- causing mutations in patients. However, problems such as mosaicism and low mutagenesis efficiency continue to pose challenges to clinical applicaUon of such approaches. Recently, a base editor （BE） system built on cytidine （C） deaminase and CRISPR/Cas9 technology was developed as an alternative method for targeted point mutagenesis in plant, yeast, and human cells. Base editors convert C in the deamination window to thymidine （T） efficiently, however, it remains unclear whether targeted base editing in mouse embryos is feasible. In this report, we generated a modified high- fidelity version of base editor 2 （HF2-BE2）, and investigated its base editing efficacy in mouse embryos. We found that HF2-BE2 could convert C to T efficiently, with up to 100% biallelic mutation efficiency in mouse embryos. Unlike BE3, HF2-BE2 could convert C to T on both the target and non-target strand, expanding the editing scope of base editors. Surprisingly, we found HF2-BE2 could also deaminate C that was proximal to the gRNA-binding region. Taken together, our work demonstrates the feasibility of generating point mutations in mouse by base editing, and underscores the need to carefully optimize base editing systems in order to eliminate proximal-site deamination.展开更多
The advances accelerated by next-generation sequencing and long-read sequencing technologies continue to provide an impetus for plant phylogenetic study.In the past decade,a large number of phylogenetic studies adopti...The advances accelerated by next-generation sequencing and long-read sequencing technologies continue to provide an impetus for plant phylogenetic study.In the past decade,a large number of phylogenetic studies adopting hundreds to thousands of genes across a wealth of clades have emerged and ushered plant phylogenetics and evolution into a new era.In the meantime,a roadmap for researchers when making decisions across different approaches for their phylogenomic research design is imminent.This review focuses on the utility of genomic data(from organelle genomes,to both reduced representation sequencing and whole-genome sequencing) in phylogenetic and evolutionary investigations,describes the baseline methodology of experimental and analytical procedures,and summarizes recent progress in flowering plant phylogenomics at the ordinal,familial,tribal,and lower levels.We also discuss the challenges,such as the adverse impact on orthology inference and phylogenetic reconstruction raised from systematic errors,and underlying biological factors,such as whole-genome duplication,hybridization/introgression,and incomplete lineage sorting,together suggesting that a bifurcating tree may not be the best model for the tree of life.Finally,we discuss promising avenues for future plant phylogenomic studies.展开更多
目的比较3种沙门菌分子血清分型方法,获得一种准确度较高的方法用来替代传统的血清凝集技术用于沙门菌血清型判定。方法对覆盖50个血清型的509株沙门菌提取核酸进行全基因组测序,根据全基因组序列分别利用多位点序列分型(MLST)、SalmonS...目的比较3种沙门菌分子血清分型方法,获得一种准确度较高的方法用来替代传统的血清凝集技术用于沙门菌血清型判定。方法对覆盖50个血清型的509株沙门菌提取核酸进行全基因组测序,根据全基因组序列分别利用多位点序列分型(MLST)、SalmonSeroPredicition以及SISTR(Salmonella in silico typing resource)3种方法在线预测获得每株菌的血清型,然后与传统血清凝集获得的血清型进行一致性比较分析,评估每种方法血清型预测的准确度。结果SISTR、MLST以及SalmonSeroPredicition预测血清型的准确率分别为96.67%、93.52%、69.16%。常见沙门菌血清型印第安纳沙门菌和鼠伤寒沙门菌血清型预测正确率最高,为100%,德尔卑沙门菌、肠炎沙门菌血清型预测正确率分别为99.17%、95.74%。3种方法均预测错误的血清型有肠炎沙门菌、德尔卑沙门菌和沙门菌的萨拉姆亚种、亚利桑那亚种和双相亚利桑那亚种等;预测错误原因主要是基因序列丢失和鞭毛抗原基因未表达。结论基于基因组序列的SISTR血清型预测方法具有较高的血清型预测准确度,在传统血清凝集难以开展或沙门菌鞭毛基因不表达的情况下,可以替代血清凝集试验进行沙门菌血清型判定。展开更多
The rapid expansion of next-generation sequencing （NGS） has generated a powerful array of approaches to address fundamental questions in biology. Several genome-partitioning strategies to sequence selected subsets o...The rapid expansion of next-generation sequencing （NGS） has generated a powerful array of approaches to address fundamental questions in biology. Several genome-partitioning strategies to sequence selected subsets of the genome have emerged in the fields of phylogenomics and evolutionary genomics. In this review, we summarize the applications, advantages and limitations of four NGS-based genome- partitioning approaches in plant phylogenomics： genome skimming, transcriptome sequencing （RNA- seq）, restriction site associated DNA sequencing （RAD-Seq）, and targeted capture （Hyb-seq）. Of these four genome-partitioning approaches, targeted capture （especially Hyb-seq） shows the greatest promise for plant phy^ogenetics over the next fex~ years. This reviex~ wi~ aid ~esea^chers in their selection of appropriate genome-partitioning approaches to address questions of evolutionary scale, where we anticipate continued development and expansion ofwhole-genome sequencing strategies in the fields of plant phylogenomics and evolutionary biology research.展开更多
Modern taxonomy has developed towards the establishment of global authoritative lists of species that assume the standard-ized principles of species recognition,at least in a given taxonomic group.However,in fungi,spe...Modern taxonomy has developed towards the establishment of global authoritative lists of species that assume the standard-ized principles of species recognition,at least in a given taxonomic group.However,in fungi,species delimitation is fre-quently subjective because it depends on the choice of a species concept and the criteria selected by a taxonomist.Contrary to it,identification of fungal species is expected to be accurate and precise because it should predict the properties that are required for applications or that are relevant in pathology.The industrial and plant-beneficial fungi from the genus Tricho-derma(Hypocreales)offer a suitable model to address this collision between species delimitation and species identification.A few decades ago,Trichoderma diversity was limited to a few dozen species.The introduction of molecular evolutionary methods resulted in the exponential expansion of Trichoderma taxonomy,with up to 50 new species recognized per year.Here,we have reviewed the genus-wide taxonomy of Trichoderma and compiled a complete inventory of all Trichoderma species and DNA barcoding material deposited in public databases(the inventory is available at the website of the Interna-tional Subcommission on Taxonomy of Trichoderma www.trich oderm a.info).Among the 375 species with valid names as of July 2020,361(96%)have been cultivated in vitro and DNA barcoded.Thus,we have developed a protocol for molecular identification of Trichoderma that requires analysis of the three DNA barcodes(ITS,tef1,and rpb2),and it is supported by online tools that are available on www.trich okey.info.We then used all the whole-genome sequenced(WGS)Trichoderma strains that are available in public databases to provide versatile practical examples of molecular identification,reveal short-comings,and discuss possible ambiguities.Based on the Trichoderma example,this study shows why the identification of a fungal species is an intricate and laborious task that requires a background in mycology,molecular biological skills,trainin展开更多
The fall armyworm(FAW),Spodoptera frugiperda,is a major pest native to the Americas that has recently invaded the Old World.Point mutations in the target-site proteins acetylcholinesterase-1(ace-1),voltage-gated sodiu...The fall armyworm(FAW),Spodoptera frugiperda,is a major pest native to the Americas that has recently invaded the Old World.Point mutations in the target-site proteins acetylcholinesterase-1(ace-1),voltage-gated sodium channel(VGSC)and ryanodine receptor(RyR)have been identified in S.frugiperda as major resistance mechanisms to organophosphate,pyrethroid and diamide insecticides respectively.Mutations in the adenosine triphosphate-binding cassette transporter C2 gene(ABCC2)have also been identified to confer resistance to Cry IF protein.In this study,we applied a whole-genome sequencing(WGS)approach to identify point mutations in the target-site genes in 150 FAW individuals collected from China,Malawi,Uganda and Brazil.This approach revealed three amino acid substitutions(A201S,G227A and F290V)of S.frugiperda ace-1,which are known to be associated with organophosphate resistance.The Brazilian population had all three ace-1 point mutations and the 227A allele(mean frequency=0.54)was the most common.Populations from China,Malawi and Uganda harbored two of the three ace-1 point mutations(A201S and F290V)with the 290V allele(0.47-0.58)as the dominant allele.Point mutations in VGSC(T929I,L932F and L1014F)and RyR(I4790M and G4946E)were not detected in any of the 150 individuals.A novel 12-bp insertion mutation in exon 15 of the ABCC2 gene was identified in some of the Brazilian individuals but absent in the invasive populations.Our results not only demonstrate robustness of the WGS-based genomic approach for detection of resistance mutations,but also provide insights for improvement of resistance management tactics in S.frugiperda.展开更多
基金The National Key Research and Development Program of China (2016YFD0801102)and the National Natural Science Foundation of China (31870198 and 31400278).
文摘The Asteraceae (Compositae),a large plant family of approximately 24 000-35 000 species,accounts for^10% of all angiosperm species and contributes a lot to plant diversity.The most representative members of the Asteraceae are the economically important chrysanthemums (Chrysanthemum L.)that diversified through reticulate evolution.Biodiversity is typically created by multiple evolutionary mechanisms such as wholegenome duplication 0NGD)or polyploidization and locally repetitive genome expansion.However,the lack of genomic data from chrysanthemum species has prevented an in-depth analysis of the evolutionary mechanisms involved in their diversification.Here,we used Oxford Nanopore long-read technologyto sequence the diploid Chrysanthemum nankingense genome,which represents one of the progenitor genomes of domesticated chrysanthemums.Our analysis revealed that the evolution of the C.nankingense genome was driven by bursts of repetitive element expansion and WGD events including a recentWGD that distinguishes chrysanthemum from sunflower,which diverged from chrysanthemum approximately 38.8 million years ago.Variations of ornamental and medicinal traits in chrysanthemums are linked to the expansion of candidate gene families by duplication events including paralogous gene duplication.Collectively,our study of the assembled reference genome offers new knowledge and resources to dissect the history and pattern of evolution and diversification of chrysanthemum plants,and also to accelerate their breeding and improvement.
基金This work was supported by the National Natural Science Foundation of China （Grant Nos. 91640119, 31601196, 81330055, 31371508, and 31671540）, the Natural Science Foundation of Guangdong Province （2016A030310206 and 2014A030312011）, the Science and Technology Planning Project of Guangdong Province （2015B020228002 and 2015A020212005）, the Guangzhou Science and Technology Project （201605030012 and 201707010085）, and the Fundamental Research Funds for the Central Universities （161gzd13 and 161gpy31）. We would also like to acknowledge the support of CA211653, CPRIT RP160462, the Welch Foundation Q-1673, and the C-BASS Shared Resource at the Dan L. Duncan Cancer Center （DLDCC） of Baylor College of Medicine （P30CA125123）.
文摘Targeted point mutagenesis through homologous recombination has been widely used in genetic studies and holds considerable promise for repairing disease- causing mutations in patients. However, problems such as mosaicism and low mutagenesis efficiency continue to pose challenges to clinical applicaUon of such approaches. Recently, a base editor （BE） system built on cytidine （C） deaminase and CRISPR/Cas9 technology was developed as an alternative method for targeted point mutagenesis in plant, yeast, and human cells. Base editors convert C in the deamination window to thymidine （T） efficiently, however, it remains unclear whether targeted base editing in mouse embryos is feasible. In this report, we generated a modified high- fidelity version of base editor 2 （HF2-BE2）, and investigated its base editing efficacy in mouse embryos. We found that HF2-BE2 could convert C to T efficiently, with up to 100% biallelic mutation efficiency in mouse embryos. Unlike BE3, HF2-BE2 could convert C to T on both the target and non-target strand, expanding the editing scope of base editors. Surprisingly, we found HF2-BE2 could also deaminate C that was proximal to the gRNA-binding region. Taken together, our work demonstrates the feasibility of generating point mutations in mouse by base editing, and underscores the need to carefully optimize base editing systems in order to eliminate proximal-site deamination.
基金supported by the Priority Research Program of the Chinese Academy of Sciences (CAS) (Grant No.XDB31000000)Large-scale Scientific Facilities of the CAS (Grant No.2017LSF-GBOWS-2)。
文摘The advances accelerated by next-generation sequencing and long-read sequencing technologies continue to provide an impetus for plant phylogenetic study.In the past decade,a large number of phylogenetic studies adopting hundreds to thousands of genes across a wealth of clades have emerged and ushered plant phylogenetics and evolution into a new era.In the meantime,a roadmap for researchers when making decisions across different approaches for their phylogenomic research design is imminent.This review focuses on the utility of genomic data(from organelle genomes,to both reduced representation sequencing and whole-genome sequencing) in phylogenetic and evolutionary investigations,describes the baseline methodology of experimental and analytical procedures,and summarizes recent progress in flowering plant phylogenomics at the ordinal,familial,tribal,and lower levels.We also discuss the challenges,such as the adverse impact on orthology inference and phylogenetic reconstruction raised from systematic errors,and underlying biological factors,such as whole-genome duplication,hybridization/introgression,and incomplete lineage sorting,together suggesting that a bifurcating tree may not be the best model for the tree of life.Finally,we discuss promising avenues for future plant phylogenomic studies.
文摘最近,随着测序成本的不断降低,数据分析策略的不断提升,全基因组测序(Whole-genome sequencing,WGS)已经在癌症、孟德尔遗传病、复杂疾病的致病基因检测中得到了一定运用,并逐步走向了临床诊断。全基因组测序不但可以检测编码区和非编码区的点突变(Single nucleotide variants,SNVs)和插入缺失(Insertions or deletions,In Dels),还可以在全基因组范围内检测拷贝数变异(Copy number variation,CNV)以及结构变异(Structure variation,SV)。文章详细地介绍了全基因组测序的标准生物信息分析流程与方法,及其在疾病研究、临床诊断中的应用,并对全基因组测序在医学遗传学中的应用与研究进展以及数据分析方面所面临的挑战进行了概述。
文摘目的比较3种沙门菌分子血清分型方法,获得一种准确度较高的方法用来替代传统的血清凝集技术用于沙门菌血清型判定。方法对覆盖50个血清型的509株沙门菌提取核酸进行全基因组测序,根据全基因组序列分别利用多位点序列分型(MLST)、SalmonSeroPredicition以及SISTR(Salmonella in silico typing resource)3种方法在线预测获得每株菌的血清型,然后与传统血清凝集获得的血清型进行一致性比较分析,评估每种方法血清型预测的准确度。结果SISTR、MLST以及SalmonSeroPredicition预测血清型的准确率分别为96.67%、93.52%、69.16%。常见沙门菌血清型印第安纳沙门菌和鼠伤寒沙门菌血清型预测正确率最高,为100%,德尔卑沙门菌、肠炎沙门菌血清型预测正确率分别为99.17%、95.74%。3种方法均预测错误的血清型有肠炎沙门菌、德尔卑沙门菌和沙门菌的萨拉姆亚种、亚利桑那亚种和双相亚利桑那亚种等;预测错误原因主要是基因序列丢失和鞭毛抗原基因未表达。结论基于基因组序列的SISTR血清型预测方法具有较高的血清型预测准确度,在传统血清凝集难以开展或沙门菌鞭毛基因不表达的情况下,可以替代血清凝集试验进行沙门菌血清型判定。
基金supported by the Large-scale Scientific Facilities of the Chinese Academy of Sciences (Grant No: 2017-LSFGBOWS-01)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB31000000)the Program of Science and Technology Talents Training of Yunnan Province (2017HA014)
文摘The rapid expansion of next-generation sequencing （NGS） has generated a powerful array of approaches to address fundamental questions in biology. Several genome-partitioning strategies to sequence selected subsets of the genome have emerged in the fields of phylogenomics and evolutionary genomics. In this review, we summarize the applications, advantages and limitations of four NGS-based genome- partitioning approaches in plant phylogenomics： genome skimming, transcriptome sequencing （RNA- seq）, restriction site associated DNA sequencing （RAD-Seq）, and targeted capture （Hyb-seq）. Of these four genome-partitioning approaches, targeted capture （especially Hyb-seq） shows the greatest promise for plant phy^ogenetics over the next fex~ years. This reviex~ wi~ aid ~esea^chers in their selection of appropriate genome-partitioning approaches to address questions of evolutionary scale, where we anticipate continued development and expansion ofwhole-genome sequencing strategies in the fields of plant phylogenomics and evolutionary biology research.
基金the grants from the National Science Foundation of China(31801939)the Fundamental Research Funds for the Central Universities(KYXK202012).
文摘Modern taxonomy has developed towards the establishment of global authoritative lists of species that assume the standard-ized principles of species recognition,at least in a given taxonomic group.However,in fungi,species delimitation is fre-quently subjective because it depends on the choice of a species concept and the criteria selected by a taxonomist.Contrary to it,identification of fungal species is expected to be accurate and precise because it should predict the properties that are required for applications or that are relevant in pathology.The industrial and plant-beneficial fungi from the genus Tricho-derma(Hypocreales)offer a suitable model to address this collision between species delimitation and species identification.A few decades ago,Trichoderma diversity was limited to a few dozen species.The introduction of molecular evolutionary methods resulted in the exponential expansion of Trichoderma taxonomy,with up to 50 new species recognized per year.Here,we have reviewed the genus-wide taxonomy of Trichoderma and compiled a complete inventory of all Trichoderma species and DNA barcoding material deposited in public databases(the inventory is available at the website of the Interna-tional Subcommission on Taxonomy of Trichoderma www.trich oderm a.info).Among the 375 species with valid names as of July 2020,361(96%)have been cultivated in vitro and DNA barcoded.Thus,we have developed a protocol for molecular identification of Trichoderma that requires analysis of the three DNA barcodes(ITS,tef1,and rpb2),and it is supported by online tools that are available on www.trich okey.info.We then used all the whole-genome sequenced(WGS)Trichoderma strains that are available in public databases to provide versatile practical examples of molecular identification,reveal short-comings,and discuss possible ambiguities.Based on the Trichoderma example,this study shows why the identification of a fungal species is an intricate and laborious task that requires a background in mycology,molecular biological skills,trainin
基金National Key Research Development Program of China(No.2019YFD0300103 to YW)the Fundamental Research Funds for the Central Universities of China(KYZ201920 to YW).
文摘The fall armyworm(FAW),Spodoptera frugiperda,is a major pest native to the Americas that has recently invaded the Old World.Point mutations in the target-site proteins acetylcholinesterase-1(ace-1),voltage-gated sodium channel(VGSC)and ryanodine receptor(RyR)have been identified in S.frugiperda as major resistance mechanisms to organophosphate,pyrethroid and diamide insecticides respectively.Mutations in the adenosine triphosphate-binding cassette transporter C2 gene(ABCC2)have also been identified to confer resistance to Cry IF protein.In this study,we applied a whole-genome sequencing(WGS)approach to identify point mutations in the target-site genes in 150 FAW individuals collected from China,Malawi,Uganda and Brazil.This approach revealed three amino acid substitutions(A201S,G227A and F290V)of S.frugiperda ace-1,which are known to be associated with organophosphate resistance.The Brazilian population had all three ace-1 point mutations and the 227A allele(mean frequency=0.54)was the most common.Populations from China,Malawi and Uganda harbored two of the three ace-1 point mutations(A201S and F290V)with the 290V allele(0.47-0.58)as the dominant allele.Point mutations in VGSC(T929I,L932F and L1014F)and RyR(I4790M and G4946E)were not detected in any of the 150 individuals.A novel 12-bp insertion mutation in exon 15 of the ABCC2 gene was identified in some of the Brazilian individuals but absent in the invasive populations.Our results not only demonstrate robustness of the WGS-based genomic approach for detection of resistance mutations,but also provide insights for improvement of resistance management tactics in S.frugiperda.
