A novelty method,frontal polymerization(FP),was employed to directly produce a series of polyacrylamide (PAM),poly(N-isopropylacrylamide)(PNIPAM) and acrylamide-N-isopropylacrylamide copolymer macroporous monoliths. F...A novelty method,frontal polymerization(FP),was employed to directly produce a series of polyacrylamide (PAM),poly(N-isopropylacrylamide)(PNIPAM) and acrylamide-N-isopropylacrylamide copolymer macroporous monoliths. Field emission scanning electronic microscope and mercury intrusion method were adopted to measure some parameters of these monoliths,such as frame,pore size distribution as well as porosity.Effects of types of monomer,thicker and surfactant on porous structure of monoliths were studied.A variet...展开更多
Dear Editor,Rapeseed(Brassica napus,AACC,2n=38),an allotetraploid oilseed crop derived from two progenitors,B.rapa(AA,2n=20)and B.oleracea(CC,2n=18),is the world’s second-largest source of vegetable oil and is extens...Dear Editor,Rapeseed(Brassica napus,AACC,2n=38),an allotetraploid oilseed crop derived from two progenitors,B.rapa(AA,2n=20)and B.oleracea(CC,2n=18),is the world’s second-largest source of vegetable oil and is extensively cultivated across different continents(Chalhoub et al.,2014;Lu et al.,2019;Wu et al.,2019).展开更多
Fig.1.The GenomeSyn tool for visualizing genome synteny and characterizing structural variations.A:The first synteny visualization map showed the detailed information of two or three genomes and can display structural...Fig.1.The GenomeSyn tool for visualizing genome synteny and characterizing structural variations.A:The first synteny visualization map showed the detailed information of two or three genomes and can display structural variations and other annotation information.B:The second type of visualization map was simple and only showed the synteny relationship between the chromosomes of two or three genomes.C:Multiplatform general GenomeSyn submission page,applicable to Windows,MAC and web platforms;other analysis files can be entered in the"other"option.The publisher would like to apologise for any inconvenience caused.展开更多
Soybean(Glycine max)is a globally important crop that serves as a primary source of edible oil and protein for both humans and animals.Cultivated soybean varieties exhibit considerable genetic diversity depending on t...Soybean(Glycine max)is a globally important crop that serves as a primary source of edible oil and protein for both humans and animals.Cultivated soybean varieties exhibit considerable genetic diversity depending on their geographical origin.Heinong 531(HN531)is an elite cultivar that was released in China in June 2021 with 22.34%seed oil,high resistance to soybean cyst nematode(SCN)race 3,and enhanced yield.However,the genetic basis for these desirable agronomic traits is unclear.In this study,we generated a high-quality genome assembly for HN531 and used it to systematically analyze genes related to agronomic traits such as resistance to SCN.The assembled genome spans 981.20 Mb,featuring a contig N50 of 19.47 Mb,and contains 58,151 predicted gene models.Pan-genomic comparison with 27 previously reported soybean genomes revealed 95,071 structural variants(SVs)of>50 bp,of which 602 were HN531-specific.Furthermore,we identified a copy number variation at rhg1 that underlies resistance to SCN,and we found elite alleles of functional genes underlying important agronomic traits such as seed oil content,adaptability,and yield.This high-quality HN531 genome can be used to explore the genetic basis for the excellent agronomic traits of this cultivar,and is a valuable resource for breeders aiming to improve HN531 and related cultivars.展开更多
Increasing number of structural variations(SVs)have been identified as causative mutations for diverse agronomic traits.However,the systematic exploration of SVs quantity,distribution,and contribution in wheat was lac...Increasing number of structural variations(SVs)have been identified as causative mutations for diverse agronomic traits.However,the systematic exploration of SVs quantity,distribution,and contribution in wheat was lacking.Here,we report high-quality gene-based and SV-based pangenomes comprising 22 hexaploid wheat assemblies showing a wide range of chromosome size,gene number,and TE component,which indicates their representativeness of wheat genetic diversity.Pan-gene analyses uncover 140,261 distinct gene families,of which only 23.2%are shared in all accessions.Moreover,we build a∼16.15 Gb graph pangenome containing 695,897 bubbles,intersecting 5132 genes and 230,307 cis-regulatory regions.Pairwise genome comparisons identify∼1,978,221 non-redundant SVs and 497 SV hotspots.Notably,the density of bubbles as well as SVs show remarkable aggregation in centromeres,which probably play an important role in chromosome plasticity and stability.As for functional SVs exploration,we identify 2769 SVs with absolute relative frequency differences exceeding 0.7 between spring and winter growth habit groups.Additionally,several reported functional genes in wheat display complex structural graphs,for example,PPD-A1,VRT-A2,and TaNAAT2-A.These findings deepen our understanding of wheat genetic diversity,providing valuable graphical pangenome and variation resources to improve the efficiency of genome-wide association mapping in wheat.展开更多
Hu sheep is an indigenous breed from the Taihu Lake Plain in China,known for its high fertility.Although Hu sheep belong to the Mongolian group,their demographic history and genetic architecture remain inconclusive.He...Hu sheep is an indigenous breed from the Taihu Lake Plain in China,known for its high fertility.Although Hu sheep belong to the Mongolian group,their demographic history and genetic architecture remain inconclusive.Here,we analyze 697 sheep genomes from representatives of Mongolian sheep breeds.Our study suggests that the ancestral Hu sheep first separated from the Mongolian group approximately 3000 years ago.As Hu sheep migrated from the north and flourished in the Taihu Lake Plain around 1000 years ago,they developed a unique genetic foundation and phenotypic characteristics,which are evident in the genomic footprints of selective sweeps and structural variation landscape.Genes associated with reproductive traits(BMPR1B and TDRD10)and horn phenotype(RXFP2)exhibit notable selective sweeps in the genome of Hu sheep.A genome-wide association analysis reveals that structural variations at LOC101110773,MAST2,and ZNF385B may significantly impact polledness,teat number,and early growth in Hu sheep,respectively.Our study offers insights into the evolutionary history of Hu sheep and may serve as a valuable genetic resource to enhance the understanding of complex traits in Hu sheep.展开更多
Avian genomes exhibit compact organization and remarkable chromosomal stability.However,the extent and mechanisms by which structural variation in avian genomes differ from those in other vertebrate lineages are poorl...Avian genomes exhibit compact organization and remarkable chromosomal stability.However,the extent and mechanisms by which structural variation in avian genomes differ from those in other vertebrate lineages are poorly explored.This study generated a diploid genome assembly for the golden pheasant(Chrysolophus pictus),a species distinguished by the vibrant plumage of males.Each haploid genome assembly included complete chromosomalmodels,incorporatingall microchromosomes.Analysis revealed extensive tandem amplification of immune-related genes across the smallest microchromosomes(dot chromosomes),with an average copy number of 54.Structural variation between the haploid genomes was primarily shaped by large insertions and deletions(indels),with minimal contributions from inversions or duplications.Approximately 28%of these large indels were associated with recent insertions of transposable elements,despite their typically low activity in bird genomes.Evidence for significant effects of transposable elements on gene expression was minimal.Evolutionary strata on the sex chromosomes were identified,along with a drastic rearrangement of the W chromosome.These analyses of the high-quality diploid genome of the golden pheasant provide valuable insights into the evolutionary patterns of structural variation in avian genomes.展开更多
The basic leucine zipper(bZIP)is an important class of transcription factors in plants,playing a critical role in plant growth and development and responses to biotic and abiotic stress.Due to gene presence/absence va...The basic leucine zipper(bZIP)is an important class of transcription factors in plants,playing a critical role in plant growth and development and responses to biotic and abiotic stress.Due to gene presence/absence variations,it is limited to identify bZIP genes based on the reference genome.Therefore,we performed the bZIP gene family analysis in the rice pan-genome.By employing a rice pan-genome,ninety-four OsbZIPs(72 core genes and 22 variable genes)were identified and divided into 11 groups in a phylogenetic tree.Based upon Ka/Ks values in 33 accessions,OsbZIPs were subjected to different selection pressures during domestication.The analysis of the effects of structural variations(SVs)on gene expression,gene structure,and conserved domains showed that SVs could significantly alter the expression levels of certain OsbZIPs,leading to gene truncation and the emergence of numerous atypical genes.Thirty-four differentially expressed OsbZIPs were identified by analyzing RNA-seq data of the Xanthomonas oryzae pv.oryzae(Xoo)infection susceptible(IR24)and resistant(IRBB67)lines under high temperature,and by counting the number of differentially expressed OsbZIPs in different subgroups.These Osb-ZIPs were found to respond to Xoo infection at an early stage and may not be involved in the mechanism of Xa4 and Xa7 resistance to Xoo.The multiple variation patterns of OsbZIP genes provide new insights into the OsbZIP genes in rice.These results provide new resources and offer new directions for functional studies of OsbZIPs.展开更多
The proximal-based decomposition method was originally proposed by Chen and Teboulle （Math. Programming, 1994, 64：81-101 for solving corrvex minimization problems. This paper extends it to solving monotone variation...The proximal-based decomposition method was originally proposed by Chen and Teboulle （Math. Programming, 1994, 64：81-101 for solving corrvex minimization problems. This paper extends it to solving monotone variational inequalities associated with separable structures with the improvements that the restrictive assumptions on the involved parameters are much relaxed, and thus makes it practical to solve the subproblems easily. Without additional assumptions, global convergence of the new method is proved under the same mild assumptions on the problem＇s data as the original method.展开更多
The seasonal variations in phytoplankton community structure were investigated for the Sanggou Bay （SGB） and the adjacent Ailian Bay （ALB） and Lidao Bay （LDB） in Shandong Peninsula,eastern China.The species comp...The seasonal variations in phytoplankton community structure were investigated for the Sanggou Bay （SGB） and the adjacent Ailian Bay （ALB） and Lidao Bay （LDB） in Shandong Peninsula,eastern China.The species composition and cell abundance of phytoplankton in the bay waters in spring （April 2011）,summer （August 2011）,autumn （October 2011）,and winter （January 2012） were examined using the Uterm6hl method.A total of 80 taxa of phytoplankton that belong to 39 genera of 3 phyla were identified.These included 64 species of 30 genera in the Phylum Bacillariophyta,13 species of 8 genera in the Phylum Dinophyta,and 3 species of 1 genus in the Phylum Chrysophyta.During the four seasons,the number of phytoplankton species （43） was the highest in spring,followed by summer and autumn （40）,and the lowest number ofphytoplankton species （35） was found in winter.Diatoms,especially Paralia sulcata （Ehrenberg） Cleve and Coscinodiscus oculus-iridis Ehrenberg,were predominant in the phytoplankton community throughout the study period,whereas the dominance of dinoflagellate appeared in summer only.The maximum cell abundance of phytoplankton was detected in summer （average 8.08 × 103 cells L-1） whereas their minimum abundance was found in autumn （average 2.60 x 103 cellsL-1）.The phytoplankton abundance was generally higher in the outer bay than in the inner bay in spring and autumn.In summer,the phytoplankton cells were mainly concentrated in the south of inner SGB,with peak abundance observed along the western coast.In winter,the distribution of phytoplankton cells showed 3 patches,with peak abundance along the western coast as well.On seasonal average,the Shannon-Wiener diversity indices of phytoplankton community ranged from 1.17 to 1.78 （autumn 〉 summer 〉 spring 〉 winter）,and the Pielou＇s evenness indices of phytoplankton ranged from 0.45 to 0.65 （autumn 〉 spring 〉 summer〉 winter）.According to the results of canonical correspondence analysis,phosphate level was the major factor that limited the occurrence of P.sulcata and C.oculus-iridis,whereas optimal temperature and low salinity were responsible for Prorocentrum blooms in summer.The detailed description of seasonal variations in phytoplankton community structure in the three bays provide reference data for future studies on marine ecosystems and mariculture in adjacent areas.展开更多
Temporal variations in multimodal structures of diurnal( D_1) and semidiurnal( D_2) internal tides were investigated on the continental slope of the Dongsha Plateau, based on 2-month moored acoustic Doppler current pr...Temporal variations in multimodal structures of diurnal( D_1) and semidiurnal( D_2) internal tides were investigated on the continental slope of the Dongsha Plateau, based on 2-month moored acoustic Doppler current profiler observations. Harmonic analysis indicated that the D_1 components( K_1 and O_1) dominated the internal tide field. The vertical structure of the K_1 constituent presented a first-mode structure while the M_2 constituent seemed to exhibit a high-mode structure. Amplitude spectra analysis of the current data revealed differences in baroclinic current amplitudes between different water depths. Temporal variations in modal structures ware analyzed, based on the D_1 and D_2 baroclinic tides extracted from the baroclinic velocity field with band-pass filters. Analysis showed that the magnitude of the D_1 internal tide current was much larger than the D_2 current, and temporal variations in the modal structure of the D_1 internal tide occurred on an approximately fortnightly cycle. The EOF analyses revealed temporal transformation of multimodal structures for D_1 and D_2 internal tides. The enhancement of the D_1 internal tide was mainly due to the superposition of K_1 and O_1, according to the temporal variation of coherent kinetic energy.展开更多
To investigate the genetic diversity of an edible fungus Pleurotus ferulae, a total of 89 wild samples collected from six geographical locations in the Xinjiang Uygur Autonomous Region of China and two geographical lo...To investigate the genetic diversity of an edible fungus Pleurotus ferulae, a total of 89 wild samples collected from six geographical locations in the Xinjiang Uygur Autonomous Region of China and two geographical locations in Italy, were analyzed using three DNA fragments including the translation elongation factor（EF1α）, the second largest subunit of t he RNA polymerase II（RPB2） and the largest subunit of the RNA polymerase II（RPB1）. The results indicated relatively abundant genetic variability in the wild resources of P. ferulae. The analysis of molecular variance（AMOVA） showed that the vast majority of the genetic variation was found within geographical populations. Both the Chinese populations and the Italian populations of P. ferulae displayed a limited genetic differentiation. The degree of differentiation between the Chinese populations and the Italian populations was obviously higher than that between the populations from the same region, and moreover the genetic differentiation among all the tested populations was correlated to the geographical distance. T he phylogeny analyses confirmed that samples from China and Italy belonged to another genetic group separated from Pleurotus eryngii. They were closely related to each other but were clustered according to their geographical origins, which implied the Chinese populations were highly differentiated from the Italian populations because of distance isolation, and the two populations from different regions might be still in the process of allopatric divergence.展开更多
"Synthetic"allopolyploids recreated by interspecific hybridization play an important role in providing novel genomic variation for crop improvement.Such synthetic allopolyploids often undergo rapid genomic s..."Synthetic"allopolyploids recreated by interspecific hybridization play an important role in providing novel genomic variation for crop improvement.Such synthetic allopolyploids often undergo rapid genomic structural variation(SV).However,how such SV arises,is inherited and fixed,and how it affects important traits,has rarely been comprehensively and quantitively studied in advanced generation synthetic lines.A better understanding of these processes will aid breeders in knowing how to best utilize synthetic allopolyploids in breeding programs.Here,we analyzed three genetic mapping populations(735 DH lines)derived from crosses between advanced synthetic and conventional Brassica napus(rapeseed)lines,using whole-genome sequencing to determine genome composition.We observed high tolerance of large structural variants,particularly toward the telomeres,and preferential selection for balanced homoeologous exchanges(duplication/deletion events between the A and C genomes resulting in retention of gene/chromosome dosage between homoeologous chromosome pairs),including stable events involving whole chromosomes("pseudoeuploidy").Given the experimental design(all three populations shared a common parent),we were able to observe that parental SV was regularly inherited,showed genetic hitchhiking effects on segregation,and was one of the major factors inducing adjacent novel and larger SV.Surprisingly,novel SV occurred at low frequencies with no significant impacts on observed fertility and yield-related traits in the advanced generation synthetic lines.However,incorporating genome-wide SV in linkage mapping explained significantly more genetic variance for traits.Our results provide a framework for detecting and understanding the occurrence and inheritance of genomic SV in breeding programs,and support the use of synthetic parents as an important source of novel trait variation.展开更多
Background During approximately 10,000 years of domestication and selection,a large number of structural variations(SVs)have emerged in the genome of pig breeds,profoundly influencing their phenotypes and the ability ...Background During approximately 10,000 years of domestication and selection,a large number of structural variations(SVs)have emerged in the genome of pig breeds,profoundly influencing their phenotypes and the ability to adapt to the local environment.SVs(≥50 bp)are widely distributed in the genome,mainly in the form of insertion(INS),mobile element insertion(MEI),deletion(DEL),duplication(DUP),inversion(INV),and translocation(TRA).While studies have investigated the SVs in pig genomes,genome-wide association studies(GWAS)-based on SVs have been rarely conducted.Results Here,we obtained a high-quality SV map containing 123,151 SVs from 15 Large White and 15 Min pigs through integrating the power of several SV tools,with 53.95%of the SVs being reported for the first time.These high-quality SVs were used to recover the population genetic structure,confirming the accuracy of genotyping.Potential functional SV loci were then identified based on positional effects and breed stratification.Finally,GWAS were performed for 36 traits by genotyping the screened potential causal loci in the F2 population according to their corresponding genomic positions.We identified a large number of loci involved in 8 carcass traits and 6 skeletal traits on chromosome 7,with FKBP5 containing the most significant SV locus for almost all traits.In addition,we found several significant loci in intramuscular fat,abdominal circumference,heart weight,and liver weight,etc.Conclusions We constructed a high-quality SV map using high-coverage sequencing data and then analyzed them by performing GWAS for 25 carcass traits,7 skeletal traits,and 4 meat quality traits to determine that SVs may affect body size between European and Chinese pig breeds.展开更多
Marine biodiversity is changing in response to altered physical environment, subsequent ecological changes as well as anthropogenic disturbances. In this study, phytoplankton samples in situ collected in the Bering Se...Marine biodiversity is changing in response to altered physical environment, subsequent ecological changes as well as anthropogenic disturbances. In this study, phytoplankton samples in situ collected in the Bering Sea in July of 1999 and 2010 were analyzed to obtain phytoplankton community structure and spatial-temporal variation between the beginning and end of this decade, and the correlation of phytoplankton community dynamics and environmental factors was investigated. A total of 5 divisions, 58 genera and 153 species of phytoplankton belonging to 3 ecological groups were identified. The vast majority of phytoplankton consisted of diatoms accounting for 66.7% of the total species and 95.2% of the total abundance. Considering differentiation in spatial extent and phytoplankton sample types, there were subtle changes in species composition, large altering in abundance and significant variation in spatial distribution between two surveys. The abundance peak area was located at the Bering Strait while sub peak was found at the Bering Sea Basin. The boreal-temperate diatom was the dominant flora, which was subsequently replaced by eurythermal and frigid-water diatom. Phytoplankton community in the Bering Sea was not a simplex uniform community but composed of deep-ocean assemblage and neritic assemblage. The deep-ocean assemblage was located in the northwestern Pacific Ocean and Bering Sea Basin, dominated by boreal-temperate species（Neodenticula seminae, Thalassiothrix longissima, Amphiprora hyperborean, Chaetoceros atlanticus, Thalassiosira trifulta, etc.） and eurychoric species（Thalassionema nitzschioides, Ch. compressus, Rhizosolenia styliformis, etc.）, and characterized by low abundance, even interspecies abundance allocations, diverse dominant species and high species diversity. The neritic assemblage was distributed on the continental shelf and slope of Bering Sea and was mainly composed of frigid-water species（Th.nordenski？ldii, Ch. furcellatus, Ch. socialis, Bacteriosira fragilis, etc.） and eurythermal and euryhaline species（L.danicus, Ch. curvisetus, Coscinodiscus curvatulus, etc.）, and it was characterized by high abundance, uneven interspecies allocations, prominent dominant species and low species diversity. Spatial-temporal variation of species composition and abundance of phytoplankton in the Bering Sea was directly controlled by surface circulation,nutrient supply and ice edge.展开更多
Structural variations(SVs),a newly discovered genetic variation,have gained increasing recognition for their importance,yet much about them remains unknown.With the completion of whole-genome sequencing projects in oi...Structural variations(SVs),a newly discovered genetic variation,have gained increasing recognition for their importance,yet much about them remains unknown.With the completion of whole-genome sequencing projects in oil crops,more SVs have been identified,revealing their types,genomic distribution,and characteristics.These findings have demonstrated the crucial roles of SVs in regulating gene expression,driving trait innovation,facilitating domestication,making this an opportune time for a systematic review.We summarized the progress of SV-related studies in oil crops,focusing on the types of SVs and their mechanisms of occurrence,the strategies and methods for SV detection,and the SVs identified in oil crops such as rapeseed,soybean,peanut,and sesame.The various types of SVs,such as presence-absence variations(PAVs),copy number variations(CNVs),and homeologous exchanges(HEs),have been shown.Along with their genomic characterization,their roles in crop domestication and breeding,and regulatory impact on gene expression and agronomic traits have also been demonstrated.This review will provide an overview of the SV research process in oil crops,enabling researchers to quickly understand key information and apply this knowledge in future studies and crop breeding.展开更多
Chromosomal rearrangements(CRs)often cause phenotypic variations.Although several major rearrangements have been identified in Triticeae,a comprehensive study of the order,timing,and breakpoints of CRs has not been co...Chromosomal rearrangements(CRs)often cause phenotypic variations.Although several major rearrangements have been identified in Triticeae,a comprehensive study of the order,timing,and breakpoints of CRs has not been conducted.Here,we reconstruct high-quality ancestral genomes for the most recent common ancestor(MRCA)of the Triticeae,and the MRCA of the wheat lineage(Triticum and Aegilops).The protogenes of MRCA of the Triticeae and the wheat lineage are 22,894 and 29,060,respectively,which were arranged in their ancestral order.By partitioning modern Triticeae chromosomes into sets of syntenic regions and linking each to the corresponding protochromosomes,we revisit the rye chromosome structural evolution and propose alternative evolutionary routes.The previously identified 4L/5L reciprocal translocation in rye and Triticum urartu is found to have occurred independently and is unlikely to be the result of chromosomal introgression following distant hybridization.We also clarify that the 4AL/7BS translocation in tetraploid wheat was a bidirectional rather than unidirectional translocation event.Lastly,we identify several breakpoints in protochromosomes that independently reoccur following Triticeae evolution,representing potential CR hotspots.This study demonstrates that these reconstructed ancestral genomes can serve as special comparative references and facilitate a better understanding of the evolution of structural rearrangements in Triticeae.展开更多
The genetic basis for Gossypium hirsutum race latifolium,the putative ancestor of cultivated upland cotton,emerging from the semi-wild races to be domesticated into cultivated upland cotton is unknown.Here,we reported...The genetic basis for Gossypium hirsutum race latifolium,the putative ancestor of cultivated upland cotton,emerging from the semi-wild races to be domesticated into cultivated upland cotton is unknown.Here,we reported a high-quality genome assembly of G.latifolium.Comparative genome analyses revealed substantial variations in both gene group composition and genomic sequences across 13 cotton genomes,including the expansion of photosynthesis-related gene groups in G.latifolium compared with other races and the pivotal contribution of structural variations(SVs)to G.hirsutum domestication.Based on the resequencing reads and constructed pan-genome of upland cotton,co-selection regions and SVs with significant frequency differences among different populations were identified.Genes located in these regions or affected by these variations may characterize the differences between G.latifolium and other races,and could be involved in maintenance of upland cotton domestication phenotypes.These findings may assist in mining genes for upland cotton improvement and improving the understanding of the genetic basis of upland cotton domestication.展开更多
The cultivated soybean（Glycine max（L.） Merr.） was distinguished from its wild progenitor Glycine soja Sieb.＆ Zucc.in growth period structure,by a shorter vegetative phase（V）,a prolonged reproductive phase（R） ...The cultivated soybean（Glycine max（L.） Merr.） was distinguished from its wild progenitor Glycine soja Sieb.＆ Zucc.in growth period structure,by a shorter vegetative phase（V）,a prolonged reproductive phase（R） and hence a larger R/V ratio.However,the genetic basis of the domestication of soybean from wild materials is unclear.Here,a panel of 123 cultivated and 97 wild accessions were genotyped using a set of 24 presence/absence variants（PAVs） while at the same time the materials were phenotyped with respect to flowering and maturity times at two trial sites located at very different latitudes.The major result of this study showed that variation at PAVs is informative for assessing patterns of genetic diversity in Glycine spp.The genotyping was largely consistent with the taxonomic status,although a few accessions were intermediate between the two major clades identified.Allelic diversity was much higher in the wild germplasm than in the cultivated materials.A significant domestication signal was detected at 11 of the PAVs at 0.01 level.In particular,this study has provided information for revealing the genetic basis of photoperiodism which was a prominent feature for the domestication of soybean.A significant marker-trait association with R/V ratio was detected at 14 of the PAVs,but stripping out population structure reduced this to three.These results will provide markers information for further finding of R/V related genes that can help to understand the domestication process and introgress novel genes in wild soybean to broaden the genetic base of modern soybean cultivars.展开更多
In the present work, structure changes during （SiO2） composites have been investigated systematically stretching of isotactic polypropylene （iPP） and iPP/silicon dioxide The or-form crystal structure of both iPP a...In the present work, structure changes during （SiO2） composites have been investigated systematically stretching of isotactic polypropylene （iPP） and iPP/silicon dioxide The or-form crystal structure of both iPP and iPP/SiO2 composites is destroyed and transforms into the mesophase as the samples are stretched at a low temperature （35℃）, while stretching at high temperatures （90℃ and 120℃） can restrain the appearance of defects and keep the perfection of crystal structure. FTIR results reveal that the stretching temperatures show no obvious difference of the effect on the orientation of pure iPP, however, the orientation of iPP/SiO2 composites is greatly changed by the tensile temperature. In the case of micron-sized SiO2 particles （average particle diameter d 〉 1 μm）, the orientation of the composites is lower than that of pure iPP at all stretching temperatures. The above results suggest that the stretching temperature and the SiO2 particle size have great influence on the structure variation and orientation behavior of iPP/SiO2 composites.展开更多
基金supported by the National Natural Science Foundation of China(No50772013)
文摘A novelty method,frontal polymerization(FP),was employed to directly produce a series of polyacrylamide (PAM),poly(N-isopropylacrylamide)(PNIPAM) and acrylamide-N-isopropylacrylamide copolymer macroporous monoliths. Field emission scanning electronic microscope and mercury intrusion method were adopted to measure some parameters of these monoliths,such as frame,pore size distribution as well as porosity.Effects of types of monomer,thicker and surfactant on porous structure of monoliths were studied.A variet...
基金funded by the Sci-Tech Innovation 2030 Agenda(2022ZD0400901)the National Natural Science Foundation of China(32100274 and 32370353)the Young Elite Scientists Sponsorship Program by CAST(2020QNRC001).
文摘Dear Editor,Rapeseed(Brassica napus,AACC,2n=38),an allotetraploid oilseed crop derived from two progenitors,B.rapa(AA,2n=20)and B.oleracea(CC,2n=18),is the world’s second-largest source of vegetable oil and is extensively cultivated across different continents(Chalhoub et al.,2014;Lu et al.,2019;Wu et al.,2019).
文摘Fig.1.The GenomeSyn tool for visualizing genome synteny and characterizing structural variations.A:The first synteny visualization map showed the detailed information of two or three genomes and can display structural variations and other annotation information.B:The second type of visualization map was simple and only showed the synteny relationship between the chromosomes of two or three genomes.C:Multiplatform general GenomeSyn submission page,applicable to Windows,MAC and web platforms;other analysis files can be entered in the"other"option.The publisher would like to apologise for any inconvenience caused.
基金supported by National Natural Science Foundation of China(32201759,32172002)Inner Mongolia Innovation Center of Biological Breeding Technology,National Key Research and Development Program of China(2021YFD1201600)+1 种基金Earmarked Fund for CARS(CARS-04-PS01)Agricultural Science and Technology Innovation Program(ASTIP).
文摘Soybean(Glycine max)is a globally important crop that serves as a primary source of edible oil and protein for both humans and animals.Cultivated soybean varieties exhibit considerable genetic diversity depending on their geographical origin.Heinong 531(HN531)is an elite cultivar that was released in China in June 2021 with 22.34%seed oil,high resistance to soybean cyst nematode(SCN)race 3,and enhanced yield.However,the genetic basis for these desirable agronomic traits is unclear.In this study,we generated a high-quality genome assembly for HN531 and used it to systematically analyze genes related to agronomic traits such as resistance to SCN.The assembled genome spans 981.20 Mb,featuring a contig N50 of 19.47 Mb,and contains 58,151 predicted gene models.Pan-genomic comparison with 27 previously reported soybean genomes revealed 95,071 structural variants(SVs)of>50 bp,of which 602 were HN531-specific.Furthermore,we identified a copy number variation at rhg1 that underlies resistance to SCN,and we found elite alleles of functional genes underlying important agronomic traits such as seed oil content,adaptability,and yield.This high-quality HN531 genome can be used to explore the genetic basis for the excellent agronomic traits of this cultivar,and is a valuable resource for breeders aiming to improve HN531 and related cultivars.
基金supported by the National Key Research and Development Program of China(2023YFF1000100 and 2023YFA0914601)the Special Funds for Science Technology Innovation and Industrial Development of Shenzhen Dapeng New District(PT202101-01).
文摘Increasing number of structural variations(SVs)have been identified as causative mutations for diverse agronomic traits.However,the systematic exploration of SVs quantity,distribution,and contribution in wheat was lacking.Here,we report high-quality gene-based and SV-based pangenomes comprising 22 hexaploid wheat assemblies showing a wide range of chromosome size,gene number,and TE component,which indicates their representativeness of wheat genetic diversity.Pan-gene analyses uncover 140,261 distinct gene families,of which only 23.2%are shared in all accessions.Moreover,we build a∼16.15 Gb graph pangenome containing 695,897 bubbles,intersecting 5132 genes and 230,307 cis-regulatory regions.Pairwise genome comparisons identify∼1,978,221 non-redundant SVs and 497 SV hotspots.Notably,the density of bubbles as well as SVs show remarkable aggregation in centromeres,which probably play an important role in chromosome plasticity and stability.As for functional SVs exploration,we identify 2769 SVs with absolute relative frequency differences exceeding 0.7 between spring and winter growth habit groups.Additionally,several reported functional genes in wheat display complex structural graphs,for example,PPD-A1,VRT-A2,and TaNAAT2-A.These findings deepen our understanding of wheat genetic diversity,providing valuable graphical pangenome and variation resources to improve the efficiency of genome-wide association mapping in wheat.
基金supported by grants from the Zhejiang Science and Technology Department Project(2023C04004)Zhejiang Science and Technology Major Program on Agricultural New Variety Breeding(2021C02068-6)+2 种基金Department of Science Technology of Huzhou City(2023GZ33)Zhejiang Team Technology Ambassador Project(Tongxiang)the National Natural Science Foundation of China(32172724).
文摘Hu sheep is an indigenous breed from the Taihu Lake Plain in China,known for its high fertility.Although Hu sheep belong to the Mongolian group,their demographic history and genetic architecture remain inconclusive.Here,we analyze 697 sheep genomes from representatives of Mongolian sheep breeds.Our study suggests that the ancestral Hu sheep first separated from the Mongolian group approximately 3000 years ago.As Hu sheep migrated from the north and flourished in the Taihu Lake Plain around 1000 years ago,they developed a unique genetic foundation and phenotypic characteristics,which are evident in the genomic footprints of selective sweeps and structural variation landscape.Genes associated with reproductive traits(BMPR1B and TDRD10)and horn phenotype(RXFP2)exhibit notable selective sweeps in the genome of Hu sheep.A genome-wide association analysis reveals that structural variations at LOC101110773,MAST2,and ZNF385B may significantly impact polledness,teat number,and early growth in Hu sheep,respectively.Our study offers insights into the evolutionary history of Hu sheep and may serve as a valuable genetic resource to enhance the understanding of complex traits in Hu sheep.
基金supported by the Foundation of Gansu Key Laboratory of Protection and Utilization for Biological Resources and Ecological Restoration in Longdong (LDSWZY202103)Natural Science Foundation of Gansu Province (22JR5RM210)to B.P.L.Gansu Ziwuling Ecosystem Observation and Research Station (20JR10RA658)。
文摘Avian genomes exhibit compact organization and remarkable chromosomal stability.However,the extent and mechanisms by which structural variation in avian genomes differ from those in other vertebrate lineages are poorly explored.This study generated a diploid genome assembly for the golden pheasant(Chrysolophus pictus),a species distinguished by the vibrant plumage of males.Each haploid genome assembly included complete chromosomalmodels,incorporatingall microchromosomes.Analysis revealed extensive tandem amplification of immune-related genes across the smallest microchromosomes(dot chromosomes),with an average copy number of 54.Structural variation between the haploid genomes was primarily shaped by large insertions and deletions(indels),with minimal contributions from inversions or duplications.Approximately 28%of these large indels were associated with recent insertions of transposable elements,despite their typically low activity in bird genomes.Evidence for significant effects of transposable elements on gene expression was minimal.Evolutionary strata on the sex chromosomes were identified,along with a drastic rearrangement of the W chromosome.These analyses of the high-quality diploid genome of the golden pheasant provide valuable insights into the evolutionary patterns of structural variation in avian genomes.
基金The National Natural Science Foundation of China(31871964,31801738,and 32100352)the Major Science and Technology Projects in Anhui Province(202003a06020009)+2 种基金Earmarked Fund for China Agriculture Research System(CARS-01-40)the Special Funds for Supporting Innovation and Entrepreneurship for Returned Oversea-Students in Anhui Province(2020LCX035)Anhui Provincial Natural Science Foundation(Youth Project,2008085QC148).
文摘The basic leucine zipper(bZIP)is an important class of transcription factors in plants,playing a critical role in plant growth and development and responses to biotic and abiotic stress.Due to gene presence/absence variations,it is limited to identify bZIP genes based on the reference genome.Therefore,we performed the bZIP gene family analysis in the rice pan-genome.By employing a rice pan-genome,ninety-four OsbZIPs(72 core genes and 22 variable genes)were identified and divided into 11 groups in a phylogenetic tree.Based upon Ka/Ks values in 33 accessions,OsbZIPs were subjected to different selection pressures during domestication.The analysis of the effects of structural variations(SVs)on gene expression,gene structure,and conserved domains showed that SVs could significantly alter the expression levels of certain OsbZIPs,leading to gene truncation and the emergence of numerous atypical genes.Thirty-four differentially expressed OsbZIPs were identified by analyzing RNA-seq data of the Xanthomonas oryzae pv.oryzae(Xoo)infection susceptible(IR24)and resistant(IRBB67)lines under high temperature,and by counting the number of differentially expressed OsbZIPs in different subgroups.These Osb-ZIPs were found to respond to Xoo infection at an early stage and may not be involved in the mechanism of Xa4 and Xa7 resistance to Xoo.The multiple variation patterns of OsbZIP genes provide new insights into the OsbZIP genes in rice.These results provide new resources and offer new directions for functional studies of OsbZIPs.
基金the National Natural Science Foundation of China(No.70671024)the Na-tional High-Tech Research and Development Program of China(863 Program)(No.2006AA11Z209)
文摘The proximal-based decomposition method was originally proposed by Chen and Teboulle （Math. Programming, 1994, 64：81-101 for solving corrvex minimization problems. This paper extends it to solving monotone variational inequalities associated with separable structures with the improvements that the restrictive assumptions on the involved parameters are much relaxed, and thus makes it practical to solve the subproblems easily. Without additional assumptions, global convergence of the new method is proved under the same mild assumptions on the problem＇s data as the original method.
基金supported by the National Program on Key Basic Research Project of China (Grant Nos. 2011CB409804 and 2015CB954002)Program for New Century Excellent Talents in University (NCET-12-1065)the National Natural Science Foundation of China (Grant No.41176136) to J. Sun
文摘The seasonal variations in phytoplankton community structure were investigated for the Sanggou Bay （SGB） and the adjacent Ailian Bay （ALB） and Lidao Bay （LDB） in Shandong Peninsula,eastern China.The species composition and cell abundance of phytoplankton in the bay waters in spring （April 2011）,summer （August 2011）,autumn （October 2011）,and winter （January 2012） were examined using the Uterm6hl method.A total of 80 taxa of phytoplankton that belong to 39 genera of 3 phyla were identified.These included 64 species of 30 genera in the Phylum Bacillariophyta,13 species of 8 genera in the Phylum Dinophyta,and 3 species of 1 genus in the Phylum Chrysophyta.During the four seasons,the number of phytoplankton species （43） was the highest in spring,followed by summer and autumn （40）,and the lowest number ofphytoplankton species （35） was found in winter.Diatoms,especially Paralia sulcata （Ehrenberg） Cleve and Coscinodiscus oculus-iridis Ehrenberg,were predominant in the phytoplankton community throughout the study period,whereas the dominance of dinoflagellate appeared in summer only.The maximum cell abundance of phytoplankton was detected in summer （average 8.08 × 103 cells L-1） whereas their minimum abundance was found in autumn （average 2.60 x 103 cellsL-1）.The phytoplankton abundance was generally higher in the outer bay than in the inner bay in spring and autumn.In summer,the phytoplankton cells were mainly concentrated in the south of inner SGB,with peak abundance observed along the western coast.In winter,the distribution of phytoplankton cells showed 3 patches,with peak abundance along the western coast as well.On seasonal average,the Shannon-Wiener diversity indices of phytoplankton community ranged from 1.17 to 1.78 （autumn 〉 summer 〉 spring 〉 winter）,and the Pielou＇s evenness indices of phytoplankton ranged from 0.45 to 0.65 （autumn 〉 spring 〉 summer〉 winter）.According to the results of canonical correspondence analysis,phosphate level was the major factor that limited the occurrence of P.sulcata and C.oculus-iridis,whereas optimal temperature and low salinity were responsible for Prorocentrum blooms in summer.The detailed description of seasonal variations in phytoplankton community structure in the three bays provide reference data for future studies on marine ecosystems and mariculture in adjacent areas.
基金Supported by the State Ministry of Science and Technology of China(Nos.2013AA122803,2013AA09A502)the National Natural Science Foundation of China(Nos.41206001,41371496)+1 种基金the Natural Science Foundation of Shandong Province of China(No.ZR2014DM017)National Key Technology Research and Development Program(No.2013BAK05B04)
文摘Temporal variations in multimodal structures of diurnal( D_1) and semidiurnal( D_2) internal tides were investigated on the continental slope of the Dongsha Plateau, based on 2-month moored acoustic Doppler current profiler observations. Harmonic analysis indicated that the D_1 components( K_1 and O_1) dominated the internal tide field. The vertical structure of the K_1 constituent presented a first-mode structure while the M_2 constituent seemed to exhibit a high-mode structure. Amplitude spectra analysis of the current data revealed differences in baroclinic current amplitudes between different water depths. Temporal variations in modal structures ware analyzed, based on the D_1 and D_2 baroclinic tides extracted from the baroclinic velocity field with band-pass filters. Analysis showed that the magnitude of the D_1 internal tide current was much larger than the D_2 current, and temporal variations in the modal structure of the D_1 internal tide occurred on an approximately fortnightly cycle. The EOF analyses revealed temporal transformation of multimodal structures for D_1 and D_2 internal tides. The enhancement of the D_1 internal tide was mainly due to the superposition of K_1 and O_1, according to the temporal variation of coherent kinetic energy.
基金funded by the National Basic Research Program of China (2014CB138305)the China Agriculture Research System (CARS24)
文摘To investigate the genetic diversity of an edible fungus Pleurotus ferulae, a total of 89 wild samples collected from six geographical locations in the Xinjiang Uygur Autonomous Region of China and two geographical locations in Italy, were analyzed using three DNA fragments including the translation elongation factor（EF1α）, the second largest subunit of t he RNA polymerase II（RPB2） and the largest subunit of the RNA polymerase II（RPB1）. The results indicated relatively abundant genetic variability in the wild resources of P. ferulae. The analysis of molecular variance（AMOVA） showed that the vast majority of the genetic variation was found within geographical populations. Both the Chinese populations and the Italian populations of P. ferulae displayed a limited genetic differentiation. The degree of differentiation between the Chinese populations and the Italian populations was obviously higher than that between the populations from the same region, and moreover the genetic differentiation among all the tested populations was correlated to the geographical distance. T he phylogeny analyses confirmed that samples from China and Italy belonged to another genetic group separated from Pleurotus eryngii. They were closely related to each other but were clustered according to their geographical origins, which implied the Chinese populations were highly differentiated from the Italian populations because of distance isolation, and the two populations from different regions might be still in the process of allopatric divergence.
基金supported by the National Natural Science Foundation of China(NSFC,31970564,32000397,32171982)the Fundamental Research Funds for the Central Universities(2662023PY004)。
文摘"Synthetic"allopolyploids recreated by interspecific hybridization play an important role in providing novel genomic variation for crop improvement.Such synthetic allopolyploids often undergo rapid genomic structural variation(SV).However,how such SV arises,is inherited and fixed,and how it affects important traits,has rarely been comprehensively and quantitively studied in advanced generation synthetic lines.A better understanding of these processes will aid breeders in knowing how to best utilize synthetic allopolyploids in breeding programs.Here,we analyzed three genetic mapping populations(735 DH lines)derived from crosses between advanced synthetic and conventional Brassica napus(rapeseed)lines,using whole-genome sequencing to determine genome composition.We observed high tolerance of large structural variants,particularly toward the telomeres,and preferential selection for balanced homoeologous exchanges(duplication/deletion events between the A and C genomes resulting in retention of gene/chromosome dosage between homoeologous chromosome pairs),including stable events involving whole chromosomes("pseudoeuploidy").Given the experimental design(all three populations shared a common parent),we were able to observe that parental SV was regularly inherited,showed genetic hitchhiking effects on segregation,and was one of the major factors inducing adjacent novel and larger SV.Surprisingly,novel SV occurred at low frequencies with no significant impacts on observed fertility and yield-related traits in the advanced generation synthetic lines.However,incorporating genome-wide SV in linkage mapping explained significantly more genetic variance for traits.Our results provide a framework for detecting and understanding the occurrence and inheritance of genomic SV in breeding programs,and support the use of synthetic parents as an important source of novel trait variation.
基金supported by the National Key R&D Program of China(2021YFD1301101)National Swine Industry Technology System(CARS-35)Agricultural Science and Technology Innovation Program(ASTIP-IAS02)。
文摘Background During approximately 10,000 years of domestication and selection,a large number of structural variations(SVs)have emerged in the genome of pig breeds,profoundly influencing their phenotypes and the ability to adapt to the local environment.SVs(≥50 bp)are widely distributed in the genome,mainly in the form of insertion(INS),mobile element insertion(MEI),deletion(DEL),duplication(DUP),inversion(INV),and translocation(TRA).While studies have investigated the SVs in pig genomes,genome-wide association studies(GWAS)-based on SVs have been rarely conducted.Results Here,we obtained a high-quality SV map containing 123,151 SVs from 15 Large White and 15 Min pigs through integrating the power of several SV tools,with 53.95%of the SVs being reported for the first time.These high-quality SVs were used to recover the population genetic structure,confirming the accuracy of genotyping.Potential functional SV loci were then identified based on positional effects and breed stratification.Finally,GWAS were performed for 36 traits by genotyping the screened potential causal loci in the F2 population according to their corresponding genomic positions.We identified a large number of loci involved in 8 carcass traits and 6 skeletal traits on chromosome 7,with FKBP5 containing the most significant SV locus for almost all traits.In addition,we found several significant loci in intramuscular fat,abdominal circumference,heart weight,and liver weight,etc.Conclusions We constructed a high-quality SV map using high-coverage sequencing data and then analyzed them by performing GWAS for 25 carcass traits,7 skeletal traits,and 4 meat quality traits to determine that SVs may affect body size between European and Chinese pig breeds.
基金The National Natural Science Foundation of China under contract Nos 41306116 and 41506217the Basic Research of the National Department of Science and Technology under contract No.GASI-01-02-04the Polar Science Strategic Research Foundation of China under contract No.20140309
文摘Marine biodiversity is changing in response to altered physical environment, subsequent ecological changes as well as anthropogenic disturbances. In this study, phytoplankton samples in situ collected in the Bering Sea in July of 1999 and 2010 were analyzed to obtain phytoplankton community structure and spatial-temporal variation between the beginning and end of this decade, and the correlation of phytoplankton community dynamics and environmental factors was investigated. A total of 5 divisions, 58 genera and 153 species of phytoplankton belonging to 3 ecological groups were identified. The vast majority of phytoplankton consisted of diatoms accounting for 66.7% of the total species and 95.2% of the total abundance. Considering differentiation in spatial extent and phytoplankton sample types, there were subtle changes in species composition, large altering in abundance and significant variation in spatial distribution between two surveys. The abundance peak area was located at the Bering Strait while sub peak was found at the Bering Sea Basin. The boreal-temperate diatom was the dominant flora, which was subsequently replaced by eurythermal and frigid-water diatom. Phytoplankton community in the Bering Sea was not a simplex uniform community but composed of deep-ocean assemblage and neritic assemblage. The deep-ocean assemblage was located in the northwestern Pacific Ocean and Bering Sea Basin, dominated by boreal-temperate species（Neodenticula seminae, Thalassiothrix longissima, Amphiprora hyperborean, Chaetoceros atlanticus, Thalassiosira trifulta, etc.） and eurychoric species（Thalassionema nitzschioides, Ch. compressus, Rhizosolenia styliformis, etc.）, and characterized by low abundance, even interspecies abundance allocations, diverse dominant species and high species diversity. The neritic assemblage was distributed on the continental shelf and slope of Bering Sea and was mainly composed of frigid-water species（Th.nordenski？ldii, Ch. furcellatus, Ch. socialis, Bacteriosira fragilis, etc.） and eurythermal and euryhaline species（L.danicus, Ch. curvisetus, Coscinodiscus curvatulus, etc.）, and it was characterized by high abundance, uneven interspecies allocations, prominent dominant species and low species diversity. Spatial-temporal variation of species composition and abundance of phytoplankton in the Bering Sea was directly controlled by surface circulation,nutrient supply and ice edge.
基金funded by the National Natural Science Foundation of China(32370693 and U20A2034)Innovation Program of Chinese Academy of Agricultural Sciences(CAAS-CSIAF-202402)+1 种基金the Young Top-notch Talent Cultivation Program of Hubei Province for Dr.Chaobo Tong,the National Key Research and Development Program of China(2021YFD1600500)Central Public-interest Scientific Institution Basal Research Fund(2021-2060302-061-027,2021-2060302-061-029).
文摘Structural variations(SVs),a newly discovered genetic variation,have gained increasing recognition for their importance,yet much about them remains unknown.With the completion of whole-genome sequencing projects in oil crops,more SVs have been identified,revealing their types,genomic distribution,and characteristics.These findings have demonstrated the crucial roles of SVs in regulating gene expression,driving trait innovation,facilitating domestication,making this an opportune time for a systematic review.We summarized the progress of SV-related studies in oil crops,focusing on the types of SVs and their mechanisms of occurrence,the strategies and methods for SV detection,and the SVs identified in oil crops such as rapeseed,soybean,peanut,and sesame.The various types of SVs,such as presence-absence variations(PAVs),copy number variations(CNVs),and homeologous exchanges(HEs),have been shown.Along with their genomic characterization,their roles in crop domestication and breeding,and regulatory impact on gene expression and agronomic traits have also been demonstrated.This review will provide an overview of the SV research process in oil crops,enabling researchers to quickly understand key information and apply this knowledge in future studies and crop breeding.
基金CAs Youth Interdisciplinary Team(JCTD-2022-06)the National Nature Science Foundation of China(31870209).
文摘Chromosomal rearrangements(CRs)often cause phenotypic variations.Although several major rearrangements have been identified in Triticeae,a comprehensive study of the order,timing,and breakpoints of CRs has not been conducted.Here,we reconstruct high-quality ancestral genomes for the most recent common ancestor(MRCA)of the Triticeae,and the MRCA of the wheat lineage(Triticum and Aegilops).The protogenes of MRCA of the Triticeae and the wheat lineage are 22,894 and 29,060,respectively,which were arranged in their ancestral order.By partitioning modern Triticeae chromosomes into sets of syntenic regions and linking each to the corresponding protochromosomes,we revisit the rye chromosome structural evolution and propose alternative evolutionary routes.The previously identified 4L/5L reciprocal translocation in rye and Triticum urartu is found to have occurred independently and is unlikely to be the result of chromosomal introgression following distant hybridization.We also clarify that the 4AL/7BS translocation in tetraploid wheat was a bidirectional rather than unidirectional translocation event.Lastly,we identify several breakpoints in protochromosomes that independently reoccur following Triticeae evolution,representing potential CR hotspots.This study demonstrates that these reconstructed ancestral genomes can serve as special comparative references and facilitate a better understanding of the evolution of structural rearrangements in Triticeae.
基金supported by the National Natural Science Foundation of China(32201873)the Key Research and Development Plan of Hubei Province(2023BBB050)。
文摘The genetic basis for Gossypium hirsutum race latifolium,the putative ancestor of cultivated upland cotton,emerging from the semi-wild races to be domesticated into cultivated upland cotton is unknown.Here,we reported a high-quality genome assembly of G.latifolium.Comparative genome analyses revealed substantial variations in both gene group composition and genomic sequences across 13 cotton genomes,including the expansion of photosynthesis-related gene groups in G.latifolium compared with other races and the pivotal contribution of structural variations(SVs)to G.hirsutum domestication.Based on the resequencing reads and constructed pan-genome of upland cotton,co-selection regions and SVs with significant frequency differences among different populations were identified.Genes located in these regions or affected by these variations may characterize the differences between G.latifolium and other races,and could be involved in maintenance of upland cotton domestication phenotypes.These findings may assist in mining genes for upland cotton improvement and improving the understanding of the genetic basis of upland cotton domestication.
基金supported by the Agricultural Science and Technology Innovation Program(ASTIP) of Chinese Academy of Agricultural Sciences and the Platform of National Crop Germplasm Resources of China(nos.2012-004 and 2013-004)
文摘The cultivated soybean（Glycine max（L.） Merr.） was distinguished from its wild progenitor Glycine soja Sieb.＆ Zucc.in growth period structure,by a shorter vegetative phase（V）,a prolonged reproductive phase（R） and hence a larger R/V ratio.However,the genetic basis of the domestication of soybean from wild materials is unclear.Here,a panel of 123 cultivated and 97 wild accessions were genotyped using a set of 24 presence/absence variants（PAVs） while at the same time the materials were phenotyped with respect to flowering and maturity times at two trial sites located at very different latitudes.The major result of this study showed that variation at PAVs is informative for assessing patterns of genetic diversity in Glycine spp.The genotyping was largely consistent with the taxonomic status,although a few accessions were intermediate between the two major clades identified.Allelic diversity was much higher in the wild germplasm than in the cultivated materials.A significant domestication signal was detected at 11 of the PAVs at 0.01 level.In particular,this study has provided information for revealing the genetic basis of photoperiodism which was a prominent feature for the domestication of soybean.A significant marker-trait association with R/V ratio was detected at 14 of the PAVs,but stripping out population structure reduced this to three.These results will provide markers information for further finding of R/V related genes that can help to understand the domestication process and introgress novel genes in wild soybean to broaden the genetic base of modern soybean cultivars.
基金financially supported by the National Natural Science Foundation of China (Nos. 51073004 and 21074141)the China National Funds for Distinguished Young Scientists (No. 50925313)
文摘In the present work, structure changes during （SiO2） composites have been investigated systematically stretching of isotactic polypropylene （iPP） and iPP/silicon dioxide The or-form crystal structure of both iPP and iPP/SiO2 composites is destroyed and transforms into the mesophase as the samples are stretched at a low temperature （35℃）, while stretching at high temperatures （90℃ and 120℃） can restrain the appearance of defects and keep the perfection of crystal structure. FTIR results reveal that the stretching temperatures show no obvious difference of the effect on the orientation of pure iPP, however, the orientation of iPP/SiO2 composites is greatly changed by the tensile temperature. In the case of micron-sized SiO2 particles （average particle diameter d 〉 1 μm）, the orientation of the composites is lower than that of pure iPP at all stretching temperatures. The above results suggest that the stretching temperature and the SiO2 particle size have great influence on the structure variation and orientation behavior of iPP/SiO2 composites.
