To further develop EST-SSR marker in rubber tree, we assembled the sequences downloaded from NCBI and Malaysia EST databases of rubber tree. By analyzing the assembled 3 733 unigenes, we identified 566 potential SSR s...To further develop EST-SSR marker in rubber tree, we assembled the sequences downloaded from NCBI and Malaysia EST databases of rubber tree. By analyzing the assembled 3 733 unigenes, we identified 566 potential SSR sites in this study. That is to say, there was one EST-SSR in every 3.96 kb. The di-nu-cleotide repeat was the most abundant type, fol owed by tri-, hexa-, tetra- and pen-ta-nucleotide repeat. The most common number of repeat units was 5, fol owed by more than 12, 6 and 7. Of 51 SSR motifs identified in this study, di-, tri-, tetra-, penta- and hexa-nucleotide repeats were 6, 26, 5, 3 and 11 types, respectively. The GA/CT di-nucleotide repeat was the most abundant motif, fol owed by TC/AG, AT/TA, CTT/GAA, TTC/AAG and TCT/AGA. In total, 158 new EST-SSRs were developed and amplified with the DNA of RRIM600 as a template. The results showed that the PCR products of 99 EST-SSRs generated clear amplifying bands. The EST-SSR markers developed in this study further enrich the number of molecular marker in rubber tree, and they wil be widely applied in DNA fingerprinting, genetic diversity, marker-assisted selection and genetic mapping, etc.展开更多
The present study was conducted to develop EST-SSR markers using the cDNA library from rice plant. Total RNA extracted from the leaves of brown plant hopper resistance gene originated from a rice cultivar “Cheongche...The present study was conducted to develop EST-SSR markers using the cDNA library from rice plant. Total RNA extracted from the leaves of brown plant hopper resistance gene originated from a rice cultivar “Cheongcheong” and sensitive rice cultivar “Nakdong” were used to synthesize a cDNA library. As a result of analyzing the cDNA library, the 17 EST-SSR primer sets were developed. This study enables to provide effective marker assisted selection (MAS) methods on the selection of white-backed planthopper resistance gene originated from a rice plant more simply, quickly and precisely. Furthermore, using this marker’s advantage of deriving from cDNA, it is possible to identify the white-backed planthopper resistance gene. In addition, this study introduces a technique for construction of a cDNA library safely without using radioactivity.展开更多
As an excellent local crop variety of Huanggang,"Huangzhou radish" has been widely promoted and its market influence is increasing day by day.Recently,the purity of "Huangzhou radish" has declined ...As an excellent local crop variety of Huanggang,"Huangzhou radish" has been widely promoted and its market influence is increasing day by day.Recently,the purity of "Huangzhou radish" has declined deeply,so it is urgent to improve and strengthen the purity and viability of "Huangzhou radish" including bad phenomena such as degeneration of varieties after self-pollination.At present,there was no SSR molecular marker can be used for genetic diversity identification of "Huangzhou radish".SSR molecular marker can provide a favorable tool to study "Huangzhou radish".In this study,"Xiakang","Hongbao"and "Huangzhou radish" were used as experimental materials,100 SSR primers were screened,and 25 pairs of SSR primers were selected.Finally,two pairs of primers were selected for identification of the purity of "Huangzhou radish" by non-denatured polyacrylamide gel electrophoresis (PAGE).The results showed that R-102 and R-112 primer pairs could amplify the special bands for "Huangzhou radish" from above three kinds of radishes.These two pairs of primers could be developed as SSR markers to identify the specificity and purity of "Huangzhou radish".Furthermore,this study provides convenient conditions for promoting the economic and social value of "Huangzhou radish".展开更多
Microsatellite markers have become one kind of the most important molecular tools used in various researches. A large number of microsatellite markers are required for the whole genome survey in the fields of molecula...Microsatellite markers have become one kind of the most important molecular tools used in various researches. A large number of microsatellite markers are required for the whole genome survey in the fields of molecular ecology,quantitative genetics and genomics. Therefore,it is extremely necessary to select several versatile,low-cost,efficient and time-and labor-saving methods to develop a large panel of microsatellite markers. In this study,we used Zhikong scallop(Chlamys farreri) as the target species to compare the efficiency of the five methods derived from three strategies for microsatellite marker development. The results showed that the strategy of constructing small insert genomic DNA library resulted in poor efficiency,while the microsatellite-enriched strategy highly improved the isolation efficiency. Although the mining public database strategy is time-and cost-saving,it is difficult to obtain a large number of microsatellite markers,mainly due to the limited sequence data of non-model species deposited in public databases. Based on the results in this study,we recommend two methods,microsatellite-enriched library construction method and FIASCO-colony hybridization method,for large-scale microsatellite marker development. Both methods were derived from the microsatellite-enriched strategy. The experimental results obtained from Zhikong scallop also provide the reference for microsatellite marker development in other species with large genomes.展开更多
Tree peonies native to China are a precious crop with ornamental,medicinal and edible oil properties,of which flare tree peony(Paeonia rockii)is one of the most significant germplasms in Paeonia.The development and ap...Tree peonies native to China are a precious crop with ornamental,medicinal and edible oil properties,of which flare tree peony(Paeonia rockii)is one of the most significant germplasms in Paeonia.The development and application of expressed sequence tag-simple sequence repeat(EST-SSR)markers are very valuable for genetic and breeding applications,but EST-SSR resources for the genus Paeonia are still limited.In this study,we first reported the development of SSRs within transcription factors(TFs)in P.rockii based on next-generation sequencing(NGS)and single-molecule long-read sequencing(SMLRS).A total of 166 EST-SSRs containing six nucleotide repeat types were identified from 959 candidate TFs associated with yield,with an average of one SSR per 5.83 unigenes.In total,102(61.45%)pairs of primers produced amplification products in the two RNA-seq cultivars.Among them,58(56.86%)pairs of primers from 18 gene families(AP2,b HLH,HSF,etc.)were identified to be polymorphic both in the parents of a linkage mapping population and in eight randomly selected accessions of P.rockii.Further,the 58 EST-SSRs indicated a high level of informativeness with PIC values ranging from 0.32 to 0.91(mean 0.70)after assessment in 37 tree peony accessions.Transferability studies indicated that the amplification ratio of the 58 pairs of primers ranged from 89.66 to 100%across seven species of Paeonia.In addition,a genetic relationship study was performed in 62 accessions.Cluster analysis using the neighbour-joining(NJ)tree demonstrated that major clusters corresponded to the known pedigree trees.Taken together,these newly developed EST-SSRs have a potential use in the conservation of tree peony germplasm and marker-assisted selection(MAS)breeding.展开更多
Yellowfin seabream Acanthopagrus latus is an important economic fish in Chinese coastal areas.Given its narrow distribution and overfishing,the genetic diversity of yellowfin seabream has been restricted for artificia...Yellowfin seabream Acanthopagrus latus is an important economic fish in Chinese coastal areas.Given its narrow distribution and overfishing,the genetic diversity of yellowfin seabream has been restricted for artificial breeding and reproduction.We performed full-length transcriptome sequencing and assembly of the genome of yellowfin seabream.A total of 68086 unigenes were obtained,with an N50 of 3391 bp on average length of 2933 bp.A total number of 50593 expressed sequence tags linked to simple sequence repeats(EST-SSR)were identified,among them dinucleotide repeats(40.6%)and AC/GT motifs(38.5%)were the most frequent.Of the 190 EST-SSRs for which PCR primer pairs were designed,150 primer pairs successfully amplified target loci and 15 SSRs showed high polymorphism.The alleles per locus ranged 6-50 on average of 25.3.The expected and observed heterozygosity varied from 0.632 to 0.969 and from 0.519 to 0.953,respectively.The polymorphic index content(PIC)values of each locus ranged 0.587-0.966 on average of 0.851.Among six yellowfin seabream population samples preliminarily tested for genetic diversity and differentiation,the Fangchenggang(FCG)population in Guangxi Province had the highest mean observed heterozygosity(H_(o))value(0.786),whereas the Zhangzhou(ZZ)population in Fujian Province had the lowest(0.678).The pairwise fixation index(Fst)values indicated significant population differentiation among six yellowfin seabream populations.This study provided evidence for the usefulness of the transcriptomic resource information and EST-SSR markers for natural resource conservation,population genetics,and breeding studies of yellowfin seabream in South China.展开更多
Chili pepper (Capsicum spp.) fruit color is an important agronomical trait. It has been known that a large deletion in the 5' upstream region of the Ccs gene generates non-red fruit color in pepper, but the accura...Chili pepper (Capsicum spp.) fruit color is an important agronomical trait. It has been known that a large deletion in the 5' upstream region of the Ccs gene generates non-red fruit color in pepper, but the accurate size and position of the deletion and whether all the non-red cultivars had the same large deletion or not were unclarified. In this study, to identify the Ccs upstream large deletion, we carried out diagnostic PCR using six forward primers at 300 - 900 bp intervals in the 5' untranslated region of Ccs with a fixed reverse primer for a yellow fruit pepper “Sonia Gold”. Then it was revealed that 4430 bp from -3234 bp position in upstream region to 1196 bp position in exon was deleted in Ccs of “Sonia Gold”. The allele having this deletion was named ccs-del. Probably this allele is substantially the same as ccs-p1 having 4879 bp deletion reported previously. Based on the sequence determined, we developed a PCR marker to distinguish ccs-del. Genotyping of 16 cultivars of C. annuum showed that 14 had ccs-del and the remaining two had another mutant allele ccs-3. This result indicates that ccs-del is the most common allele and widely shared in non-red fruit cultivars in C. annuum. Genotyping of 16 cultivars of C. chinense clarified that one cultivar each possessed ccs-del and ccs-3. These results indicate that major alleles responsible for non-red fruit color in C. annuum were shared across species throughout interspecific introgression.展开更多
While the importance of molecular marker technology was realized more than two decades ago,high-throughput marker development came into vogue only after the availability of hundreds of thousands of sequences in public...While the importance of molecular marker technology was realized more than two decades ago,high-throughput marker development came into vogue only after the availability of hundreds of thousands of sequences in public databases.Many examples now exist where markers are being used routinely in breeding programs for marker-assisted selection(MAS) of traits of interest or marker assisted recovery of genome of interest.Genetic analysis with thousands to tens of thousands of markers is now possible due to the...展开更多
It was helpful for the wheat improvement to evaluate the genetic resources of Triticum turgidum L. ssp. turgidum landraces. In this study, 68 turgidum landraces accessions, belonging to four geographic populations in ...It was helpful for the wheat improvement to evaluate the genetic resources of Triticum turgidum L. ssp. turgidum landraces. In this study, 68 turgidum landraces accessions, belonging to four geographic populations in China, were investigated by using EST-SSR markers. A total of 63 alleles were detected on 22 EST-SSR loci, and the number of alleles on each locus ranged from 1 to 5, with an average of 2.9. The results of the analysis of molecular variance （AMOVA） indicated that 92.5% of the total variations was attributed to the genetic variations within population, whereas only 7.5% variations among populations. Although the four populations had similar genetic diversity parameters, Sichuan population was yet distinguished from other populations when comparing the population samples in pairs. Significant correlations were detected by the statistic analysis among six genetic diversity parameters among each other. The selection difference between heterozygosty and homozygosty was also observed among different EST-SSR locus. The genetic similarity （GS） ranged from 0.18 to 0.98, with the mean of 0.72, and all accessions could be clustered into 7 groups. The dendrogram suggested that the genetic relationships among turgidum accessions evaluated by EST-SSR markers were unrelated to their geographic distributions. These results implied that turgidum landraces from China had the unique characters of genetic diversity.展开更多
Notopterygium incisum C. C. Ting ex H. T. Chang(Apiaceae) is an endangered perennial herb in China. The lack of transcriptomic and genomic resources for N. incisum greatly hinders studies of its population genetics an...Notopterygium incisum C. C. Ting ex H. T. Chang(Apiaceae) is an endangered perennial herb in China. The lack of transcriptomic and genomic resources for N. incisum greatly hinders studies of its population genetics and conservation. In this study, we employed RNA-seq technology to characterize transcriptomes for the flowers, leaves, and stems of this endangered herb. A total of 56 million clean reads were assembled into 120,716 unigenes with an N50 length of 850 bp. Among these unigenes, 70,245(58.19%) were successfully annotated and 65,965(54.64%) were identified as coding sequences based on their similarities with sequences in public databases. We identified 21 unigenes that had significant relationships with cold tolerance in N. incisum according to gene ontology(GO) annotation analysis. In addition, 13,149 simple sequence repeats(SSRs) and 85,681 single nucleotide polymorphisms were detected as potential molecular genetic markers. Ninety-six primer pairs of SSRs were randomly selected to validate their amplification efficiency and polymorphism. Nineteen SSR loci exhibited polymorphism in three natural populations of N. incisum. These results provide valuable resources to facilitate future functional genomics and conservation genetics studies of N. incisum.展开更多
Microsatellite marker （or Simple Sequence Repeate, SSR） is a marker technology based on DNA molecular length poly morphism. It is also one of the most commonly used molecular markers. Traditional SSR marker developm...Microsatellite marker （or Simple Sequence Repeate, SSR） is a marker technology based on DNA molecular length poly morphism. It is also one of the most commonly used molecular markers. Traditional SSR marker development methods are relatively time-consuming and mostly relying on the known genome sequence information while recently developed methods of SSR marker based on RAPD, ISSR-PCR SSR, the use of hybrid options, sequence tag SSR library access and screening EST-SSR have been widely used. This paper gave an overview of the methods mentioned above for the development of SSR markers.展开更多
The next - generation sequencing platform has revealed the genomic sequences of numer-ous plant species that are ideal resources for simple sequence repeat （SSR） locus screening. In this stud-y, we performed a ...The next - generation sequencing platform has revealed the genomic sequences of numer-ous plant species that are ideal resources for simple sequence repeat （SSR） locus screening. In this stud-y, we performed a comparative genomic SSR analysis on 9 sequenced plants. This showed that the total numbers of mono-, di-, tri-, tetra-, penta-, and hexa-nucleotide repeat SSRs and compound SSRs ranged from 45,552 to 326,319, and the frequencies varied from 177.9 to 573.7 with an average of 401. 3 per Mb. The SSR numbers decreased as the size of the repeat unit increased. The mono-and di-nucleotide SSRs and compound SSRs accounted for more than 78% of the total SSRs in these plants. A/T-rich re-peat motifs were generally dominant in most plants. The sizes of different SSRs varied from 10 to 7288 bp, but at least 85% of them were less than 45 bp. The polymorphism rates of different SSR types ranged from 1.5% to 14.4% in Sesamum indicum, and the mono- and di-nucleotide SSRs displayed the highest polymorphism, followed by the compound SSRs （11.2% ） . These results provide comprehensive insight into the SSR loci of plants and serve as an experimental reference for improvement of SSR marker devel-opment based on plant genomic sequences.展开更多
基金Supported by the Fundamental Scientific Research Funds for Chinese Academy of Tropical Agricultural Sciences(1630022013028)National Natural Science Foundation of China(30960310,31200514,31270651)~~
文摘To further develop EST-SSR marker in rubber tree, we assembled the sequences downloaded from NCBI and Malaysia EST databases of rubber tree. By analyzing the assembled 3 733 unigenes, we identified 566 potential SSR sites in this study. That is to say, there was one EST-SSR in every 3.96 kb. The di-nu-cleotide repeat was the most abundant type, fol owed by tri-, hexa-, tetra- and pen-ta-nucleotide repeat. The most common number of repeat units was 5, fol owed by more than 12, 6 and 7. Of 51 SSR motifs identified in this study, di-, tri-, tetra-, penta- and hexa-nucleotide repeats were 6, 26, 5, 3 and 11 types, respectively. The GA/CT di-nucleotide repeat was the most abundant motif, fol owed by TC/AG, AT/TA, CTT/GAA, TTC/AAG and TCT/AGA. In total, 158 new EST-SSRs were developed and amplified with the DNA of RRIM600 as a template. The results showed that the PCR products of 99 EST-SSRs generated clear amplifying bands. The EST-SSR markers developed in this study further enrich the number of molecular marker in rubber tree, and they wil be widely applied in DNA fingerprinting, genetic diversity, marker-assisted selection and genetic mapping, etc.
文摘The present study was conducted to develop EST-SSR markers using the cDNA library from rice plant. Total RNA extracted from the leaves of brown plant hopper resistance gene originated from a rice cultivar “Cheongcheong” and sensitive rice cultivar “Nakdong” were used to synthesize a cDNA library. As a result of analyzing the cDNA library, the 17 EST-SSR primer sets were developed. This study enables to provide effective marker assisted selection (MAS) methods on the selection of white-backed planthopper resistance gene originated from a rice plant more simply, quickly and precisely. Furthermore, using this marker’s advantage of deriving from cDNA, it is possible to identify the white-backed planthopper resistance gene. In addition, this study introduces a technique for construction of a cDNA library safely without using radioactivity.
基金Supported by the Hubei Special Project for Development of Science and Technology in Local by Central Guidance(2018ZYYD019)
文摘As an excellent local crop variety of Huanggang,"Huangzhou radish" has been widely promoted and its market influence is increasing day by day.Recently,the purity of "Huangzhou radish" has declined deeply,so it is urgent to improve and strengthen the purity and viability of "Huangzhou radish" including bad phenomena such as degeneration of varieties after self-pollination.At present,there was no SSR molecular marker can be used for genetic diversity identification of "Huangzhou radish".SSR molecular marker can provide a favorable tool to study "Huangzhou radish".In this study,"Xiakang","Hongbao"and "Huangzhou radish" were used as experimental materials,100 SSR primers were screened,and 25 pairs of SSR primers were selected.Finally,two pairs of primers were selected for identification of the purity of "Huangzhou radish" by non-denatured polyacrylamide gel electrophoresis (PAGE).The results showed that R-102 and R-112 primer pairs could amplify the special bands for "Huangzhou radish" from above three kinds of radishes.These two pairs of primers could be developed as SSR markers to identify the specificity and purity of "Huangzhou radish".Furthermore,this study provides convenient conditions for promoting the economic and social value of "Huangzhou radish".
基金supported by ‘863’ Program (2006AA10A408 and 2006AA10A411), NSFC30571417, NYHYZX07-047, 2005DKA30470, 2006BAD09A10 and NCET-06-0594.
文摘Microsatellite markers have become one kind of the most important molecular tools used in various researches. A large number of microsatellite markers are required for the whole genome survey in the fields of molecular ecology,quantitative genetics and genomics. Therefore,it is extremely necessary to select several versatile,low-cost,efficient and time-and labor-saving methods to develop a large panel of microsatellite markers. In this study,we used Zhikong scallop(Chlamys farreri) as the target species to compare the efficiency of the five methods derived from three strategies for microsatellite marker development. The results showed that the strategy of constructing small insert genomic DNA library resulted in poor efficiency,while the microsatellite-enriched strategy highly improved the isolation efficiency. Although the mining public database strategy is time-and cost-saving,it is difficult to obtain a large number of microsatellite markers,mainly due to the limited sequence data of non-model species deposited in public databases. Based on the results in this study,we recommend two methods,microsatellite-enriched library construction method and FIASCO-colony hybridization method,for large-scale microsatellite marker development. Both methods were derived from the microsatellite-enriched strategy. The experimental results obtained from Zhikong scallop also provide the reference for microsatellite marker development in other species with large genomes.
基金supported by the National Key Research and Development Project(2019YFD1001500)the National Natural Science Foundation of China(31471898)。
文摘Tree peonies native to China are a precious crop with ornamental,medicinal and edible oil properties,of which flare tree peony(Paeonia rockii)is one of the most significant germplasms in Paeonia.The development and application of expressed sequence tag-simple sequence repeat(EST-SSR)markers are very valuable for genetic and breeding applications,but EST-SSR resources for the genus Paeonia are still limited.In this study,we first reported the development of SSRs within transcription factors(TFs)in P.rockii based on next-generation sequencing(NGS)and single-molecule long-read sequencing(SMLRS).A total of 166 EST-SSRs containing six nucleotide repeat types were identified from 959 candidate TFs associated with yield,with an average of one SSR per 5.83 unigenes.In total,102(61.45%)pairs of primers produced amplification products in the two RNA-seq cultivars.Among them,58(56.86%)pairs of primers from 18 gene families(AP2,b HLH,HSF,etc.)were identified to be polymorphic both in the parents of a linkage mapping population and in eight randomly selected accessions of P.rockii.Further,the 58 EST-SSRs indicated a high level of informativeness with PIC values ranging from 0.32 to 0.91(mean 0.70)after assessment in 37 tree peony accessions.Transferability studies indicated that the amplification ratio of the 58 pairs of primers ranged from 89.66 to 100%across seven species of Paeonia.In addition,a genetic relationship study was performed in 62 accessions.Cluster analysis using the neighbour-joining(NJ)tree demonstrated that major clusters corresponded to the known pedigree trees.Taken together,these newly developed EST-SSRs have a potential use in the conservation of tree peony germplasm and marker-assisted selection(MAS)breeding.
基金Supported by the National Key R&D Program of China (No. 2019YFD0901202)the Key-Area Research and Development Program of Guangdong Province (No. 2021B0202020002)+1 种基金the China Postdoctoral Science Foundation (No. 2021M693677)the Yellow Fin Bream Seed System Building Project (2021)
文摘Yellowfin seabream Acanthopagrus latus is an important economic fish in Chinese coastal areas.Given its narrow distribution and overfishing,the genetic diversity of yellowfin seabream has been restricted for artificial breeding and reproduction.We performed full-length transcriptome sequencing and assembly of the genome of yellowfin seabream.A total of 68086 unigenes were obtained,with an N50 of 3391 bp on average length of 2933 bp.A total number of 50593 expressed sequence tags linked to simple sequence repeats(EST-SSR)were identified,among them dinucleotide repeats(40.6%)and AC/GT motifs(38.5%)were the most frequent.Of the 190 EST-SSRs for which PCR primer pairs were designed,150 primer pairs successfully amplified target loci and 15 SSRs showed high polymorphism.The alleles per locus ranged 6-50 on average of 25.3.The expected and observed heterozygosity varied from 0.632 to 0.969 and from 0.519 to 0.953,respectively.The polymorphic index content(PIC)values of each locus ranged 0.587-0.966 on average of 0.851.Among six yellowfin seabream population samples preliminarily tested for genetic diversity and differentiation,the Fangchenggang(FCG)population in Guangxi Province had the highest mean observed heterozygosity(H_(o))value(0.786),whereas the Zhangzhou(ZZ)population in Fujian Province had the lowest(0.678).The pairwise fixation index(Fst)values indicated significant population differentiation among six yellowfin seabream populations.This study provided evidence for the usefulness of the transcriptomic resource information and EST-SSR markers for natural resource conservation,population genetics,and breeding studies of yellowfin seabream in South China.
文摘Chili pepper (Capsicum spp.) fruit color is an important agronomical trait. It has been known that a large deletion in the 5' upstream region of the Ccs gene generates non-red fruit color in pepper, but the accurate size and position of the deletion and whether all the non-red cultivars had the same large deletion or not were unclarified. In this study, to identify the Ccs upstream large deletion, we carried out diagnostic PCR using six forward primers at 300 - 900 bp intervals in the 5' untranslated region of Ccs with a fixed reverse primer for a yellow fruit pepper “Sonia Gold”. Then it was revealed that 4430 bp from -3234 bp position in upstream region to 1196 bp position in exon was deleted in Ccs of “Sonia Gold”. The allele having this deletion was named ccs-del. Probably this allele is substantially the same as ccs-p1 having 4879 bp deletion reported previously. Based on the sequence determined, we developed a PCR marker to distinguish ccs-del. Genotyping of 16 cultivars of C. annuum showed that 14 had ccs-del and the remaining two had another mutant allele ccs-3. This result indicates that ccs-del is the most common allele and widely shared in non-red fruit cultivars in C. annuum. Genotyping of 16 cultivars of C. chinense clarified that one cultivar each possessed ccs-del and ccs-3. These results indicate that major alleles responsible for non-red fruit color in C. annuum were shared across species throughout interspecific introgression.
文摘While the importance of molecular marker technology was realized more than two decades ago,high-throughput marker development came into vogue only after the availability of hundreds of thousands of sequences in public databases.Many examples now exist where markers are being used routinely in breeding programs for marker-assisted selection(MAS) of traits of interest or marker assisted recovery of genome of interest.Genetic analysis with thousands to tens of thousands of markers is now possible due to the...
基金the National High Technology Research and Development Program of China (863 Program,2006AA10Z179 and 2006AA10Z1F8)the National Excellent Doctoral Dissertation of China (200357 and 200458)the Key Technologies R&D Program of China (2006BAD01A02-23 and 2006BAD13B02)
文摘It was helpful for the wheat improvement to evaluate the genetic resources of Triticum turgidum L. ssp. turgidum landraces. In this study, 68 turgidum landraces accessions, belonging to four geographic populations in China, were investigated by using EST-SSR markers. A total of 63 alleles were detected on 22 EST-SSR loci, and the number of alleles on each locus ranged from 1 to 5, with an average of 2.9. The results of the analysis of molecular variance （AMOVA） indicated that 92.5% of the total variations was attributed to the genetic variations within population, whereas only 7.5% variations among populations. Although the four populations had similar genetic diversity parameters, Sichuan population was yet distinguished from other populations when comparing the population samples in pairs. Significant correlations were detected by the statistic analysis among six genetic diversity parameters among each other. The selection difference between heterozygosty and homozygosty was also observed among different EST-SSR locus. The genetic similarity （GS） ranged from 0.18 to 0.98, with the mean of 0.72, and all accessions could be clustered into 7 groups. The dendrogram suggested that the genetic relationships among turgidum accessions evaluated by EST-SSR markers were unrelated to their geographic distributions. These results implied that turgidum landraces from China had the unique characters of genetic diversity.
基金supported by the National Natural Science Foundation of China (31470400)Shaanxi Provincial Key Laboratory Project of Department of Education (grant no. 17JS135)+2 种基金the Shaanxi Provincial Education Department Serves Local Special Projects (grant no. 2018JC032)the programme for the Key Research and Development Plan in Shaanxi province (grant no. 2018ZDXM-SF-014)Public health specialty in the Department of Traditional Chinese Medicine (grants no. 2011-76, 201207002, 201213, 2013-135, 201407002, 2014-76, 2015-78, 2016-44, 2017-66)
文摘Notopterygium incisum C. C. Ting ex H. T. Chang(Apiaceae) is an endangered perennial herb in China. The lack of transcriptomic and genomic resources for N. incisum greatly hinders studies of its population genetics and conservation. In this study, we employed RNA-seq technology to characterize transcriptomes for the flowers, leaves, and stems of this endangered herb. A total of 56 million clean reads were assembled into 120,716 unigenes with an N50 length of 850 bp. Among these unigenes, 70,245(58.19%) were successfully annotated and 65,965(54.64%) were identified as coding sequences based on their similarities with sequences in public databases. We identified 21 unigenes that had significant relationships with cold tolerance in N. incisum according to gene ontology(GO) annotation analysis. In addition, 13,149 simple sequence repeats(SSRs) and 85,681 single nucleotide polymorphisms were detected as potential molecular genetic markers. Ninety-six primer pairs of SSRs were randomly selected to validate their amplification efficiency and polymorphism. Nineteen SSR loci exhibited polymorphism in three natural populations of N. incisum. These results provide valuable resources to facilitate future functional genomics and conservation genetics studies of N. incisum.
文摘Microsatellite marker （or Simple Sequence Repeate, SSR） is a marker technology based on DNA molecular length poly morphism. It is also one of the most commonly used molecular markers. Traditional SSR marker development methods are relatively time-consuming and mostly relying on the known genome sequence information while recently developed methods of SSR marker based on RAPD, ISSR-PCR SSR, the use of hybrid options, sequence tag SSR library access and screening EST-SSR have been widely used. This paper gave an overview of the methods mentioned above for the development of SSR markers.
文摘The next - generation sequencing platform has revealed the genomic sequences of numer-ous plant species that are ideal resources for simple sequence repeat （SSR） locus screening. In this stud-y, we performed a comparative genomic SSR analysis on 9 sequenced plants. This showed that the total numbers of mono-, di-, tri-, tetra-, penta-, and hexa-nucleotide repeat SSRs and compound SSRs ranged from 45,552 to 326,319, and the frequencies varied from 177.9 to 573.7 with an average of 401. 3 per Mb. The SSR numbers decreased as the size of the repeat unit increased. The mono-and di-nucleotide SSRs and compound SSRs accounted for more than 78% of the total SSRs in these plants. A/T-rich re-peat motifs were generally dominant in most plants. The sizes of different SSRs varied from 10 to 7288 bp, but at least 85% of them were less than 45 bp. The polymorphism rates of different SSR types ranged from 1.5% to 14.4% in Sesamum indicum, and the mono- and di-nucleotide SSRs displayed the highest polymorphism, followed by the compound SSRs （11.2% ） . These results provide comprehensive insight into the SSR loci of plants and serve as an experimental reference for improvement of SSR marker devel-opment based on plant genomic sequences.
