Every breeding program that aims to create new and improved cultivars with desired traits mostly relies on information related to genetic diversity.Therefore,molecular characterization of germplasms is important to ob...Every breeding program that aims to create new and improved cultivars with desired traits mostly relies on information related to genetic diversity.Therefore,molecular characterization of germplasms is important to obtain target cultivars with desirable traits.Sweet potato[Ipomoea batatas(L.)Lam]is widely considered the world’s most important crop,with great diversity in morphological and phenotypic traits.The genetic diversity of 20 sweet potato germplasms originating from Bangladesh,CIP,Philippines,Taiwan,and Malaysia were compared,which was accomplished by genetic diversity analysis by exploring 20 microsatellite DNA markers for germplasm characterization and utilization.This information was effective in differentiating or clustering the sweet potato genotypes.A total of 64 alleles were generated using the 20 primers throughout the 20 germplasm samples,with locus IBS97 having the highest number of alleles(5),whereas locus IbU33 had the fewest alleles(2).The alleles varied in size from 105(IbU31)to 213 base pairs(IBS34).The Polymorphism Information Content(PIC)values for the loci IbL46 and IBS97 varied from 0.445 to 0.730.IBS97 has the highest number of effective alleles(3.704),compared to an average of 2.520.The average Shannon’s diversity index(H)was 1.003,ranging from 0.673 in IbU3 to 1.432 in IBS97.The value of gene flow(Nm)varied between 0.000 and 0.005,with an average of 0.003,whereas genetic differentiation(FST-values)ranged between 0.901 and 1.000.The sweet potato germplasm included in this study had a broad genetic base.SP1 vs.SP9 and SP12 vs.SP18 germplasm pairings had the greatest genetic distance(GD=0.965),while SP1 vs.SP2 germplasm couples had the least genetic diversity(GD=0.093).Twenty genotypes were classified into two groups in the UPGMA dendrogram,with 16 genotypes classified as group“A”and the remaining four genotypes,SP10,SP18,SP19,and SP20,classified as group“B.”According to cluster analysis,the anticipated heterozygosity(gene diversity)of Nei(1973)was 0.591 on average.In summary,SSR markers successfully evaluated the genetic relationships among the sweet potato accessions used and generated a high level of polymorphism.The results of the present study will be useful for the management of germplasm,improvement of the current breeding strategies,and the release of new cultivars as varieties.展开更多
The cultivation of grapes is severely impacted by the emergence of downy mildew (DM) disease which negatively affects quality and yield possibly resulting in heavy losses. Due to certain shortcomings in the usage of f...The cultivation of grapes is severely impacted by the emergence of downy mildew (DM) disease which negatively affects quality and yield possibly resulting in heavy losses. Due to certain shortcomings in the usage of fungicides and the development of new cultivars by plant breeding, marker assisted selection (MAS) will be an efficient alternative method to introduce desired genes into the cultivated varieties in a short time period. The Simple sequence repeats (SSR) markers seem to be the most popular genetic marker of choice for MAS. In the present study, we identified 14 new SSR markers in <i>RPV1</i> locus that are associated with downy mildew resistance in grapes. The characterization of the identified markers was carried out on the basis of various parameters such as types of repeat motifs, number of repeats, different classes and structure of microsatellites. Additionally, SSR genotyping in 56 different grape accessions was done to determine the susceptibility or resistance of these accessions to DM.展开更多
Octopus minor(Sasaki 1920)is an important commercial cephalopod species in China.This species has declined sharply in recent years.Hence,genetic studies of O.minor are imperative to exploit and manage the wild resourc...Octopus minor(Sasaki 1920)is an important commercial cephalopod species in China.This species has declined sharply in recent years.Hence,genetic studies of O.minor are imperative to exploit and manage the wild resource.In this study,46192 microsatellite loci were discovered in 70174 unigenes from the transcriptomic data.Among all of the simple sequence repeat(SSR)unit categories,di-nucleotide and tri-nucleotide SSRs accounted for 45.26%and 14.49%,respectively.A total of 108 SSRs were tested,of which 21 were neutral and polymorphic.Seven SSRs were selected for genetics analyses of the O.minor populations in the Bohai Sea,the Yellow Sea,and the southwest coast of the Taiwan Strait region.Significant pairwise F_(st) values were detected among the samples.The UPGMA tree based on genetic distances suggested that the sampling locations could be arranged in three clusters.These markers are evidence that the populations in this region may be structured,with samples from Penghu differing remarkably from those in northern China.The present study characterized genetic markers for population assessment,management,and conservation of O.minor.展开更多
Simple sequence repeats (SSRs) or microsatellites, as genetic markers, are ubiquitous in genomes of various organisms. The analysis of SSR in rhizobia genome provides useful information for a variety of applications...Simple sequence repeats (SSRs) or microsatellites, as genetic markers, are ubiquitous in genomes of various organisms. The analysis of SSR in rhizobia genome provides useful information for a variety of applications in population genetics of rhizobia. We analyzed the occurrences, relative abundance, and relative density of SSRs, the most common in Bradyrhizobium japonicum, Mesorhizobium loti, and Sinorhizobium meliloti genomes se- quenced in the microorganisms tandem repeats database, and SSRs in the three species genomes were compared with each other. The result showed that there were 1 410, 859, and 638 SSRs in B. japonicum, M. loti, and S. meliloti genomes, respectively. In the genomes of B. japonicum, M. loti, and S. meliloti, tetranucleotide, pentanucleotide, and hexanucleotide repeats were more abundant and indicated higher mutation rates in these species. The least abundance was mononucleotide repeat. The SSRs type and distribution were similar among these species.展开更多
Simple sequence repeats (SSRs) exist in both eukaryotic and prokaryotic genomes and are the most popular genetic markers, but the SSRs of mosquito genomes are still not well understood. In this study, we identified an...Simple sequence repeats (SSRs) exist in both eukaryotic and prokaryotic genomes and are the most popular genetic markers, but the SSRs of mosquito genomes are still not well understood. In this study, we identified and analyzed the SSRs in 23 mosquito species using Drosophila melanogaster as reference at the whole-genome level. The results show that SSR numbers (33 076-560 175/genome) and genome sizes (574.57-1342.21 Mb) are significantly positively correlated (R~= 0.8992, P < 0.01), but the correlation in individual species varies in these mosquito species. In six types of SSR, mono- to trinucleotide SSRs are dominant with cumulative percentages of 95.14%-99.00% and densities of 195.65/Mb-787.51/Mb, whereas tetra- to hexanucleotide SSRs are rare with 1.12%-4.22% and 3.76/Mb-40.23/Mb. The (A/T)n,(AC/GT)n and (AGC/GCT)n are the most frequent motifs in mononucleotide, dinucleotide and trinucleotide SSRs, respectively, and the motif frequencies of tetra- to hexanucleotide SSRs appear to be species-specific. The 10-20 bp length of SSRs are dominant with the number of 11() 561 ± 93 482 and the frequency of 87.25%± 5.73% on average, and the number and frequency decline with the increase oflength. Most SSRs(83.34%± 7.72%) are located in intergenic regions, followed by intron regions (11.59%± 5.59%), exon regions (3.74%± 1.95%), and untranslated regions (1.32%± 1.39%). The mono-, di- and trinucleotide SSRs are the main SSRs in both gene regions (98.55%± 0.85%) and exon regions (99.27%± 0.52%). An average of 42.52% of total genes contains SSRs, and the preference for SSR occurrenee in different gene subcategories are species-specific. The study provides useful insights into the SSR diversity, characteristics and distribution in 23 mosquito species of genomes.展开更多
Mungbean (Vigna radiata (L.) Wilczek) is a unique species in its ability to fix atmospheric nitrogen, with early maturity, and relatively good drought resistance. We used 454 sequencing technology for transcriptom...Mungbean (Vigna radiata (L.) Wilczek) is a unique species in its ability to fix atmospheric nitrogen, with early maturity, and relatively good drought resistance. We used 454 sequencing technology for transcriptome sequencing. A total of 150 159 and 142 993 reads produced 5 254 and 6 374 large contigs (〉_500 bp) with an average length of 833 and 853 for Sunhwa and Jangan, respectively. Functional annotation to known sequences yielded 41.34% and 41.74% unigenes for Jangan and Sunhwa. A higher number of simple sequence repeat (SSR) motifs was identified in Jangan (1 630) compared with that of Sunhwa (1 334). A similar SSR distribution pattern was observed in both varieties. A total of 8 249 single nucleotide polymorphisms (SNPs) and indels with 2 098 high-confidence candidates were identified in the two mungbean varieties. The average distance between individual SNPs was -860 bp. Our report demonstrates the utility of transcriptomic data for implementing a functional annotation and development of genetic markers. We also provide large resource sequence data for mungbean improvement programs.展开更多
Dynamic mutations of simple sequence repeats (SSRs) have been demonstrated to affect normal gene function and cause different genetic disorders. Several conserved and even partial functional SSR patterns are discove...Dynamic mutations of simple sequence repeats (SSRs) have been demonstrated to affect normal gene function and cause different genetic disorders. Several conserved and even partial functional SSR patterns are discovered in inherited orthologous disease genes. To explore a wide range of SSRs in genetic diseases, a comprehensive system focusing on identifying orthologous SSRs of disease genes through a comparative genomics mechanism is constructed and accomplished by adopting online Mendelian inheritance in man (OMIM) and NCBI HomoloGene databases as the fundamental resources of human genetic diseases and homologous gene information. In addition, an efficient and effective algorithm for searching SSR patterns is also developed for providing annotated SSR information among various model species. By integrating these data resources and mining technologies, biologists and doctors can systematically retrieve novel and important conserved SSR information among orthologous disease genes. The proposed system, Orthologous SSR for Disease Genes (OSDG), is the first comprehensive framework for identifying orthologous SSRs as potential causative factors of genetic disorders and is freely available at http://osdg.cs.ntou.edu.tw/.展开更多
The genetic diversity of 41 parental lines popularized in commercial hybrid rice production in China was studied by using cluster analysis of morphological traits and simple sequence repeat (SSR) markers. Forty-one ...The genetic diversity of 41 parental lines popularized in commercial hybrid rice production in China was studied by using cluster analysis of morphological traits and simple sequence repeat (SSR) markers. Forty-one entries were assigned into two clusters (i.e. early or medium-maturing cluster; medium or late-maturing cluster) and further assigned into six sub-clusters based on morphological trait cluster analysis, The early or medium-maturing cluster was composed of 15 maintainer lines, four early-maturing restorer lines and two thermo-sensitive genic male sterile lines, and the medium or late-maturing cluster included 16 restorer lines and 4 medium or late-maturing maintainer lines. Moreover, the SSR cluster analysis classified 41 entries into two groups (i.e, maintainer line group and restorer line group) and seven sub-groups. The maintainer line group consisted of all 19 maintainer lines, two thermo-sensitive genic male sterile lines, while the restorer line group was composed of all 20 restorer lines. The SSR analysis fitted better with the pedigree information. From the views on hybrid rice breeding, the results suggested that SSR analysis might be a better method to study the diversity of parental lines in indica hybrid rice.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
Inheritance analysis and gene mapping of the glabrous trait were conducted using the crosses between a pubescent rice material Chuanxiang 29B (an aromatic elite maintainer line of hybrid rice), and two glabrous rice...Inheritance analysis and gene mapping of the glabrous trait were conducted using the crosses between a pubescent rice material Chuanxiang 29B (an aromatic elite maintainer line of hybrid rice), and two glabrous rice materials, Lemont and R2 (R2 is a new restorer line of hybrid rice). All F1 plants from the two crosses had pubescent leaves, confirming that the pubescence trait in Chuanxiang 29B is dominant over the glabrous trait. In F2 individuals, the segregation ratio of three pubescent to one glabrous plant suggests that a single glabrous gene was present in Lemont and R2. Using the bulked segregant analysis, the linkage analysis of the simple sequence repeat markers showed that the glabrous gene, gl-1, was flanked by GL311 and GL8 with the genetic distances of 0.19 and 0.92 cM on chromosome 5, respectively.展开更多
Salt stress is a major problem in most of the rice growing areas in the world. A major QTLSaltol associated with salt tolerance at the seedling stage has been mapped on chromosome 1 in rice.This study aimed to charact...Salt stress is a major problem in most of the rice growing areas in the world. A major QTLSaltol associated with salt tolerance at the seedling stage has been mapped on chromosome 1 in rice.This study aimed to characterize the haplotype diversity at Saltol and additional QTLs associated withsalt tolerance. Salt tolerance at the seedling stage was assessed in 54 rice genotypes in the scale of 1to 9 score at EC = 10 dSm^-1 under controlled environmental conditions. Seven new breeding linesincluding three KMR3/O. rufipogon introgression lines showed similar salt tolerant ability as FL478 andcan be good sources of new genes/alleles for salt tolerance. Simple sequence repeat (SSR) markerRM289 showed only two alleles and RM8094 showed seven alleles. Polymorphic information contentvalue varied from 0.55 for RM289 to 0.99 for RM8094 and RM493. Based on 14 SSR markers, the 54lines were clearly separated into two major clusters. Fourteen haplotypes were identified based onSaltol linked markers with FL478 as the reference. Alleles of RM8094 and RM3412 can discriminatebetween the salt tolerant and susceptible genotypes clearly and hence can be useful in marker-assistedselection at the seedling stage. Other markers RM10720 on chromosome 1 and RM149 and RM264 onchromosome 8 can also distinguish tolerant and susceptible lines but with lesser stringency.展开更多
Weedy rice exerts a severe impact on rice production by competing for sunlight, water and nutrients. This study assayed the population structure, genetic diversity and origin of Northeast Asia weedy rice by using 48 s...Weedy rice exerts a severe impact on rice production by competing for sunlight, water and nutrients. This study assayed the population structure, genetic diversity and origin of Northeast Asia weedy rice by using 48 simple sequence repeat markers. The results showed that weedy rice in Northeast Asia had a high genetic diversity, with Shannon's diversity index (I) of 0.748 and the heterozygosity (He) of 0.434. In each regional population, I value varied widely. The widest range of I (0.228-0.489) was observed in the weedy rice of Eastern China, which was larger than that of Northeast China and Korea (0.168-0.270). The F-statistics of regional populations (Fis, Fit and Fst) also showed higher values in the weedy rice of Eastern China than those of Northeast China and Korea All weedy rice accessions were grouped into two clusters in the unweighted pair group method with arithmetic mean cluster analysis dendrogram, namely Eastern China branch and Northeastern China plus Korea branch. There was significant differentiation in genetic characteristics in weedy rice of northeastern and eastern Asia, especially in Eastern China.展开更多
Abundance of simple sequence repeat (SSR) in Citrus sequences from EMBL database was investigated by usingcomputer program MISA (MIcroSAtellite), which aimed to provide useful information for the development of SSR ma...Abundance of simple sequence repeat (SSR) in Citrus sequences from EMBL database was investigated by usingcomputer program MISA (MIcroSAtellite), which aimed to provide useful information for the development of SSR markers.Among 32 896 sequences of Citrus, 4 987 SSRs were found in 4 167 sequences and the average distance between SSRs wasapproximately 3.5 kb. Mononucleotide repeats (50.6%) were the most abundant repeats. And di-, tri-, tetra-, penta- andhexa-nucleotide repeats were 22.8, 25.2, 1, 0.08, and 0.36%, respectively. The most abundant motif was A/T followed indescending order by AG/CT, AC/GT, AT/TA. AAT/ATT, AAG/CTT, AGC/CGT, ACG/CTG and C/G. They comprised about90% of all microsatellites. Ten primer pairs were designed, and three of them produced clear visible bands among Citrusand its related genera.展开更多
The resource of Fenneropenaeus chinensis has declined sharply due to excessive fishing intensity,ecological changes and diseases.In order to supplement the fishing yield and restore resources of F.chinensis,the releva...The resource of Fenneropenaeus chinensis has declined sharply due to excessive fishing intensity,ecological changes and diseases.In order to supplement the fishing yield and restore resources of F.chinensis,the relevant authorities have carried out the activities of stock enhancement and releasing.It can increase biomass and recover resources.However,compared with increasing biomass,there were still few reports on its effect on the recovery of resources.Resource recovery is a process related to whether the released individuals can form a reproductive population.Up to now,there has been a lack of evidence whether the released F.chinensis can complete the entire life history,and form reproduction population.In this study,gravid female shrimp after spawning migration were captured from coastal waters of Haiyang,Qingdao,and Yellow Sea.After identifying parentage relationships using simple sequence repeat(SSR)and mtDNA haplotype,it was finally confirmed that there were eight released individuals in the recapture samples.It was confirmed for the first time that at least part of the released F.chinensis can complete overwintering and reproductive migration,and maintain the migration habits as their wild counterparts.Therefore,we infered that the released shrimp can reproduce under natural conditions,these F.chinensis can form reproductive populations theoretically if without human intervention.These results indicated that enhancenment and release activities have a positive effect on resource recovery.展开更多
The sea star Asterias amurensis is widely viewed as a severe“marine pest”because of its broad feeding habits.Over the past few decades,A.amurensis undergoes massive and sporadic population outbreaks worldwide,causin...The sea star Asterias amurensis is widely viewed as a severe“marine pest”because of its broad feeding habits.Over the past few decades,A.amurensis undergoes massive and sporadic population outbreaks worldwide,causing extensive economic and ecological losses to the local aquaculture industry and marine ecosystem.Understanding the genetic diversity and population structure of A.amurensis can provide vital information for resource management.By analyzing the polymorphism of the mitochondrial cytochrome C oxidase subunit I(COI)gene and ten simple sequence repeat(SSR)microsatellites markers,the genetic diversity and population structure of A.amurensis of four populations along the northern coast of China was uncovered.A total of 36 haplotypes were identified,and a main haplotype was found in four populations.The Qingdao(QD)population displayed the highest genetic diversity among all the populations.The AMOVA and pairwise F_(st)showed that there was small but statistically significant population differentiation among the four populations,especially between QD and Weihai(WH).Moreover,the principal component analysis(PCA)and admixture analysis showed that several individuals in Yantai(YT)and Dalian(DL)had little genetic association with other individuals.Overall,this study provided useful information of the genetic diversity and population structure of A.amurensis and will contribute to the resource management of A.amurensis in China.展开更多
Peanut,with high oil content,has been a major oil and food crop globally.The compositions of the fatty acids are the common factors in determining the oil quality.In the present study,an F2 segregated population with ...Peanut,with high oil content,has been a major oil and food crop globally.The compositions of the fatty acids are the common factors in determining the oil quality.In the present study,an F2 segregated population with 140 individuals derived from the cross of Weihua8(a cultivar)and 12L49(a line with high oleic acid concentration)was used to construct a genetic map and conduct QTL mapping analysis.A total of 103 polymorphic SSR primers were utilized for genotyping the RILs and finally generating the SSR loci.Within the 103 SSR loci,a genetic linkage map,covering a total length of 3592.35 cM of the whole peanut genome,was constructed.Based on the genetic map,sixteen QTLs located on nine linkage groups related to peanut fatty acids were finally identified.Among them,four QTLs were detected associated with various traits simultaneously,which showed genetic stability in relation to fatty acids of peanut.Except for the QTLs for oleic acid,linoleic acid,and linolenic acid,three novel QTLs for arachidic acid and behenic acid were also detected.These QTLs might be helpful for further fine mapping analysis and marker-assisted selection of fatty acids in peanut.展开更多
Chloroplast simple sequence repeat (cpSSR) markers in Citrus were developed and successfully used to analyze chloroplast genome inheritance of Citrus somatic hybrids. Twenty-two previously reported cpSSR primer pairs ...Chloroplast simple sequence repeat (cpSSR) markers in Citrus were developed and successfully used to analyze chloroplast genome inheritance of Citrus somatic hybrids. Twenty-two previously reported cpSSR primer pairs from pine (Pinus thunbergii Parl.), rice (Otyza sativa L.) and tobacco (Nicotiana tabacum L.) were tested in Citrus, nine of which could amplify intensive PCR products by agarose gel electrophoresis. Chloroplast genome inheritance of Citrus somatic hybrids from nine fusions was then analyzed, and five of the nine pre-screened primer pairs showed polymorphisms by polyacrylamide gel electrophoresis. The results revealed the random inheritance nature of chloroplast genome in all analyzed Citrus somatic hybrids, which was in agreement with previous reports based on RFLP or CAPS analyses. It was also shown that cpSSR is a more efficient tool in chloroplast genome analyses of somatic hybrids in higher plants, compared with the conventional RFLP or CAPS analyses.展开更多
Genetic relationships of eight species of genus Betula were evaluated using ISSR marks. A total of 236 loci were generated from 17 ISSR primers. Percentage of polymorphic bands (PPB) varied from 5.93 to 19.92. The hig...Genetic relationships of eight species of genus Betula were evaluated using ISSR marks. A total of 236 loci were generated from 17 ISSR primers. Percentage of polymorphic bands (PPB) varied from 5.93 to 19.92. The highest and the lowest level of genetic differentiation were detected in B. ovalifolia and B. maximowicziana Regel respectively. In these eight species, genetic diversity of birch (HT) was 24.38 %, and the genetic variation (GST ) interspecies was accounting for 79.36% of total genetic variation. According to the cluster results of genetic distance, the eight species were classified into three groups as B. davurica, B. ovalifolia, B. platyphylla and B. pendula for one group; B. schmidtii, B. costata and B. ermanii Cham. var. communis for one group, and B. maximowicziana Regel for another group. The result of cluster is consistent with traditional morphological classification.展开更多
Genetic diversity of 18 processing apple varieties and two fresh varieties were evaluated using 12 simple sequence repeats (SSR) primer pairs previously identified in Malus domestica Borkh. A total of 87 alleles in ...Genetic diversity of 18 processing apple varieties and two fresh varieties were evaluated using 12 simple sequence repeats (SSR) primer pairs previously identified in Malus domestica Borkh. A total of 87 alleles in 10 loci were detected using 10 polymorphic SSR markers selected within the range of 5-14 alleles per locus. All the 20 varieties could be distinguished using two primer pairs and they were divided into four groups using cluster analysis. The genetic similarity (GS) of groups analyzed using cluster analysis varied from 0.14 to 0.83. High acid variety Avrolles separated from other varieties with GS less than 0.42. The second group contained Longfeng and Dolgo from Northeast of China, the inherited genes of Chinese crab apple. The five cider varieties with high tannin contents, namely, Dabinette, Frequin rouge, Kermerrien, M.Menard, and D.Coetligne were clustered into the third group. The fourth group was mainly composed of 12 juice and fresh varieties. Principal coordinate analysis (PCO) also divided all the varieties into four groups. Juice and fresh apple varieties, Longfeng and Dolgo were clustered together, respectively, using both the analyses. Both the analyses showed there was much difference between cider and juice varieties, cider and fresh varieties, as well as Chinese crab apple and western European crab apple, whereas juice varieties and fresh varieties had a similar genetic background. The genetic diversity and differentiation could be sufficiently reflected by combining the two analytical methods.展开更多
基金The work was financially supported by National Agricultural Technology Program-II Project(NATP-2)BARC Component Bangladesh Agricultural Research Council,Farmgate,Dhaka-1215+2 种基金Bangladesh Agricultural Research Institute(BARI),Joydebpur,Gazipur 1701The work was partially supported by the Taif University Researchers Supporting Project No.(TURSP-2020/39)Taif University,Taif,Saudi Arabia.
文摘Every breeding program that aims to create new and improved cultivars with desired traits mostly relies on information related to genetic diversity.Therefore,molecular characterization of germplasms is important to obtain target cultivars with desirable traits.Sweet potato[Ipomoea batatas(L.)Lam]is widely considered the world’s most important crop,with great diversity in morphological and phenotypic traits.The genetic diversity of 20 sweet potato germplasms originating from Bangladesh,CIP,Philippines,Taiwan,and Malaysia were compared,which was accomplished by genetic diversity analysis by exploring 20 microsatellite DNA markers for germplasm characterization and utilization.This information was effective in differentiating or clustering the sweet potato genotypes.A total of 64 alleles were generated using the 20 primers throughout the 20 germplasm samples,with locus IBS97 having the highest number of alleles(5),whereas locus IbU33 had the fewest alleles(2).The alleles varied in size from 105(IbU31)to 213 base pairs(IBS34).The Polymorphism Information Content(PIC)values for the loci IbL46 and IBS97 varied from 0.445 to 0.730.IBS97 has the highest number of effective alleles(3.704),compared to an average of 2.520.The average Shannon’s diversity index(H)was 1.003,ranging from 0.673 in IbU3 to 1.432 in IBS97.The value of gene flow(Nm)varied between 0.000 and 0.005,with an average of 0.003,whereas genetic differentiation(FST-values)ranged between 0.901 and 1.000.The sweet potato germplasm included in this study had a broad genetic base.SP1 vs.SP9 and SP12 vs.SP18 germplasm pairings had the greatest genetic distance(GD=0.965),while SP1 vs.SP2 germplasm couples had the least genetic diversity(GD=0.093).Twenty genotypes were classified into two groups in the UPGMA dendrogram,with 16 genotypes classified as group“A”and the remaining four genotypes,SP10,SP18,SP19,and SP20,classified as group“B.”According to cluster analysis,the anticipated heterozygosity(gene diversity)of Nei(1973)was 0.591 on average.In summary,SSR markers successfully evaluated the genetic relationships among the sweet potato accessions used and generated a high level of polymorphism.The results of the present study will be useful for the management of germplasm,improvement of the current breeding strategies,and the release of new cultivars as varieties.
文摘The cultivation of grapes is severely impacted by the emergence of downy mildew (DM) disease which negatively affects quality and yield possibly resulting in heavy losses. Due to certain shortcomings in the usage of fungicides and the development of new cultivars by plant breeding, marker assisted selection (MAS) will be an efficient alternative method to introduce desired genes into the cultivated varieties in a short time period. The Simple sequence repeats (SSR) markers seem to be the most popular genetic marker of choice for MAS. In the present study, we identified 14 new SSR markers in <i>RPV1</i> locus that are associated with downy mildew resistance in grapes. The characterization of the identified markers was carried out on the basis of various parameters such as types of repeat motifs, number of repeats, different classes and structure of microsatellites. Additionally, SSR genotyping in 56 different grape accessions was done to determine the susceptibility or resistance of these accessions to DM.
基金supported by the National Natural Science Foundation of China(No.31672257)the National Key Research and Development Program of China(No.2020YFD0900705).
文摘Octopus minor(Sasaki 1920)is an important commercial cephalopod species in China.This species has declined sharply in recent years.Hence,genetic studies of O.minor are imperative to exploit and manage the wild resource.In this study,46192 microsatellite loci were discovered in 70174 unigenes from the transcriptomic data.Among all of the simple sequence repeat(SSR)unit categories,di-nucleotide and tri-nucleotide SSRs accounted for 45.26%and 14.49%,respectively.A total of 108 SSRs were tested,of which 21 were neutral and polymorphic.Seven SSRs were selected for genetics analyses of the O.minor populations in the Bohai Sea,the Yellow Sea,and the southwest coast of the Taiwan Strait region.Significant pairwise F_(st) values were detected among the samples.The UPGMA tree based on genetic distances suggested that the sampling locations could be arranged in three clusters.These markers are evidence that the populations in this region may be structured,with samples from Penghu differing remarkably from those in northern China.The present study characterized genetic markers for population assessment,management,and conservation of O.minor.
基金the program of Key Sci-ence and Technology Research from the Department of Science and Technology of General Bureau of Land Reclamation of Heilongjiang Province, China (HNKXIV-02-03-03)
文摘Simple sequence repeats (SSRs) or microsatellites, as genetic markers, are ubiquitous in genomes of various organisms. The analysis of SSR in rhizobia genome provides useful information for a variety of applications in population genetics of rhizobia. We analyzed the occurrences, relative abundance, and relative density of SSRs, the most common in Bradyrhizobium japonicum, Mesorhizobium loti, and Sinorhizobium meliloti genomes se- quenced in the microorganisms tandem repeats database, and SSRs in the three species genomes were compared with each other. The result showed that there were 1 410, 859, and 638 SSRs in B. japonicum, M. loti, and S. meliloti genomes, respectively. In the genomes of B. japonicum, M. loti, and S. meliloti, tetranucleotide, pentanucleotide, and hexanucleotide repeats were more abundant and indicated higher mutation rates in these species. The least abundance was mononucleotide repeat. The SSRs type and distribution were similar among these species.
基金the National Natural Science Foundation of China(31672363,31372265)the Par-Eu Scholars Program(20136666)+2 种基金the Coordinated Research Project of the International Atomic En?ergy Agency(18268)the National Key Program of Science and Tech no logy Foundation Work of China(2015FY210300)and the Science and Technology Research Project of Chongqing Municipal Education Commission(KJ 1600304).
文摘Simple sequence repeats (SSRs) exist in both eukaryotic and prokaryotic genomes and are the most popular genetic markers, but the SSRs of mosquito genomes are still not well understood. In this study, we identified and analyzed the SSRs in 23 mosquito species using Drosophila melanogaster as reference at the whole-genome level. The results show that SSR numbers (33 076-560 175/genome) and genome sizes (574.57-1342.21 Mb) are significantly positively correlated (R~= 0.8992, P < 0.01), but the correlation in individual species varies in these mosquito species. In six types of SSR, mono- to trinucleotide SSRs are dominant with cumulative percentages of 95.14%-99.00% and densities of 195.65/Mb-787.51/Mb, whereas tetra- to hexanucleotide SSRs are rare with 1.12%-4.22% and 3.76/Mb-40.23/Mb. The (A/T)n,(AC/GT)n and (AGC/GCT)n are the most frequent motifs in mononucleotide, dinucleotide and trinucleotide SSRs, respectively, and the motif frequencies of tetra- to hexanucleotide SSRs appear to be species-specific. The 10-20 bp length of SSRs are dominant with the number of 11() 561 ± 93 482 and the frequency of 87.25%± 5.73% on average, and the number and frequency decline with the increase oflength. Most SSRs(83.34%± 7.72%) are located in intergenic regions, followed by intron regions (11.59%± 5.59%), exon regions (3.74%± 1.95%), and untranslated regions (1.32%± 1.39%). The mono-, di- and trinucleotide SSRs are the main SSRs in both gene regions (98.55%± 0.85%) and exon regions (99.27%± 0.52%). An average of 42.52% of total genes contains SSRs, and the preference for SSR occurrenee in different gene subcategories are species-specific. The study provides useful insights into the SSR diversity, characteristics and distribution in 23 mosquito species of genomes.
基金support of the "Cooperative Research Program for Agriculture Science & Technology Development (Project No. 200908FHT020609001)" Rural Development Administration (RDA),Republic of Korea
文摘Mungbean (Vigna radiata (L.) Wilczek) is a unique species in its ability to fix atmospheric nitrogen, with early maturity, and relatively good drought resistance. We used 454 sequencing technology for transcriptome sequencing. A total of 150 159 and 142 993 reads produced 5 254 and 6 374 large contigs (〉_500 bp) with an average length of 833 and 853 for Sunhwa and Jangan, respectively. Functional annotation to known sequences yielded 41.34% and 41.74% unigenes for Jangan and Sunhwa. A higher number of simple sequence repeat (SSR) motifs was identified in Jangan (1 630) compared with that of Sunhwa (1 334). A similar SSR distribution pattern was observed in both varieties. A total of 8 249 single nucleotide polymorphisms (SNPs) and indels with 2 098 high-confidence candidates were identified in the two mungbean varieties. The average distance between individual SNPs was -860 bp. Our report demonstrates the utility of transcriptomic data for implementing a functional annotation and development of genetic markers. We also provide large resource sequence data for mungbean improvement programs.
文摘Dynamic mutations of simple sequence repeats (SSRs) have been demonstrated to affect normal gene function and cause different genetic disorders. Several conserved and even partial functional SSR patterns are discovered in inherited orthologous disease genes. To explore a wide range of SSRs in genetic diseases, a comprehensive system focusing on identifying orthologous SSRs of disease genes through a comparative genomics mechanism is constructed and accomplished by adopting online Mendelian inheritance in man (OMIM) and NCBI HomoloGene databases as the fundamental resources of human genetic diseases and homologous gene information. In addition, an efficient and effective algorithm for searching SSR patterns is also developed for providing annotated SSR information among various model species. By integrating these data resources and mining technologies, biologists and doctors can systematically retrieve novel and important conserved SSR information among orthologous disease genes. The proposed system, Orthologous SSR for Disease Genes (OSDG), is the first comprehensive framework for identifying orthologous SSRs as potential causative factors of genetic disorders and is freely available at http://osdg.cs.ntou.edu.tw/.
文摘The genetic diversity of 41 parental lines popularized in commercial hybrid rice production in China was studied by using cluster analysis of morphological traits and simple sequence repeat (SSR) markers. Forty-one entries were assigned into two clusters (i.e. early or medium-maturing cluster; medium or late-maturing cluster) and further assigned into six sub-clusters based on morphological trait cluster analysis, The early or medium-maturing cluster was composed of 15 maintainer lines, four early-maturing restorer lines and two thermo-sensitive genic male sterile lines, and the medium or late-maturing cluster included 16 restorer lines and 4 medium or late-maturing maintainer lines. Moreover, the SSR cluster analysis classified 41 entries into two groups (i.e, maintainer line group and restorer line group) and seven sub-groups. The maintainer line group consisted of all 19 maintainer lines, two thermo-sensitive genic male sterile lines, while the restorer line group was composed of all 20 restorer lines. The SSR analysis fitted better with the pedigree information. From the views on hybrid rice breeding, the results suggested that SSR analysis might be a better method to study the diversity of parental lines in indica hybrid rice.
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.
基金supported by the grants of the National High Technology Research and Development Program of China(Grant No.2006AA100101)the ‘948’program of China(Grant No.2006-G1)the National Technology Foundation from Ministry of Agriculture,China(Grant No.2006BAD01A01-1)
文摘Inheritance analysis and gene mapping of the glabrous trait were conducted using the crosses between a pubescent rice material Chuanxiang 29B (an aromatic elite maintainer line of hybrid rice), and two glabrous rice materials, Lemont and R2 (R2 is a new restorer line of hybrid rice). All F1 plants from the two crosses had pubescent leaves, confirming that the pubescence trait in Chuanxiang 29B is dominant over the glabrous trait. In F2 individuals, the segregation ratio of three pubescent to one glabrous plant suggests that a single glabrous gene was present in Lemont and R2. Using the bulked segregant analysis, the linkage analysis of the simple sequence repeat markers showed that the glabrous gene, gl-1, was flanked by GL311 and GL8 with the genetic distances of 0.19 and 0.92 cM on chromosome 5, respectively.
基金Financial support of Department of Biotechnology,Government of India[Grant Nos.BT/AB/FG-2(PH-II)2009 and BT/PR13357/AGR/02/695/2009]
文摘Salt stress is a major problem in most of the rice growing areas in the world. A major QTLSaltol associated with salt tolerance at the seedling stage has been mapped on chromosome 1 in rice.This study aimed to characterize the haplotype diversity at Saltol and additional QTLs associated withsalt tolerance. Salt tolerance at the seedling stage was assessed in 54 rice genotypes in the scale of 1to 9 score at EC = 10 dSm^-1 under controlled environmental conditions. Seven new breeding linesincluding three KMR3/O. rufipogon introgression lines showed similar salt tolerant ability as FL478 andcan be good sources of new genes/alleles for salt tolerance. Simple sequence repeat (SSR) markerRM289 showed only two alleles and RM8094 showed seven alleles. Polymorphic information contentvalue varied from 0.55 for RM289 to 0.99 for RM8094 and RM493. Based on 14 SSR markers, the 54lines were clearly separated into two major clusters. Fourteen haplotypes were identified based onSaltol linked markers with FL478 as the reference. Alleles of RM8094 and RM3412 can discriminatebetween the salt tolerant and susceptible genotypes clearly and hence can be useful in marker-assistedselection at the seedling stage. Other markers RM10720 on chromosome 1 and RM149 and RM264 onchromosome 8 can also distinguish tolerant and susceptible lines but with lesser stringency.
基金funded by Shanghai Municipal Key Task Projects of Prospering Agriculture by Science and Technology Plan in China (Grant No. Hu Nong Ke Gong Zi 2008: 2-1)
文摘Weedy rice exerts a severe impact on rice production by competing for sunlight, water and nutrients. This study assayed the population structure, genetic diversity and origin of Northeast Asia weedy rice by using 48 simple sequence repeat markers. The results showed that weedy rice in Northeast Asia had a high genetic diversity, with Shannon's diversity index (I) of 0.748 and the heterozygosity (He) of 0.434. In each regional population, I value varied widely. The widest range of I (0.228-0.489) was observed in the weedy rice of Eastern China, which was larger than that of Northeast China and Korea (0.168-0.270). The F-statistics of regional populations (Fis, Fit and Fst) also showed higher values in the weedy rice of Eastern China than those of Northeast China and Korea All weedy rice accessions were grouped into two clusters in the unweighted pair group method with arithmetic mean cluster analysis dendrogram, namely Eastern China branch and Northeastern China plus Korea branch. There was significant differentiation in genetic characteristics in weedy rice of northeastern and eastern Asia, especially in Eastern China.
基金The authors acknowledge the financial support by the National Natural Science Foundation of China(30170472,30471201)International Plant Genetic Resources Institute(IPGRI/AM-LOA-002-2002).
文摘Abundance of simple sequence repeat (SSR) in Citrus sequences from EMBL database was investigated by usingcomputer program MISA (MIcroSAtellite), which aimed to provide useful information for the development of SSR markers.Among 32 896 sequences of Citrus, 4 987 SSRs were found in 4 167 sequences and the average distance between SSRs wasapproximately 3.5 kb. Mononucleotide repeats (50.6%) were the most abundant repeats. And di-, tri-, tetra-, penta- andhexa-nucleotide repeats were 22.8, 25.2, 1, 0.08, and 0.36%, respectively. The most abundant motif was A/T followed indescending order by AG/CT, AC/GT, AT/TA. AAT/ATT, AAG/CTT, AGC/CGT, ACG/CTG and C/G. They comprised about90% of all microsatellites. Ten primer pairs were designed, and three of them produced clear visible bands among Citrusand its related genera.
基金Laoshan Laboratory under contract No.LSKJ202203803。
文摘The resource of Fenneropenaeus chinensis has declined sharply due to excessive fishing intensity,ecological changes and diseases.In order to supplement the fishing yield and restore resources of F.chinensis,the relevant authorities have carried out the activities of stock enhancement and releasing.It can increase biomass and recover resources.However,compared with increasing biomass,there were still few reports on its effect on the recovery of resources.Resource recovery is a process related to whether the released individuals can form a reproductive population.Up to now,there has been a lack of evidence whether the released F.chinensis can complete the entire life history,and form reproduction population.In this study,gravid female shrimp after spawning migration were captured from coastal waters of Haiyang,Qingdao,and Yellow Sea.After identifying parentage relationships using simple sequence repeat(SSR)and mtDNA haplotype,it was finally confirmed that there were eight released individuals in the recapture samples.It was confirmed for the first time that at least part of the released F.chinensis can complete overwintering and reproductive migration,and maintain the migration habits as their wild counterparts.Therefore,we infered that the released shrimp can reproduce under natural conditions,these F.chinensis can form reproductive populations theoretically if without human intervention.These results indicated that enhancenment and release activities have a positive effect on resource recovery.
基金Supported by the International Science Partnership Program of the Chinese Academy of Sciences(No.133137KYSB20200002)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA23050304)the Natural Science Foundation of Shandong Province(Nos.ZR2021MC151,ZR2021QD158)。
文摘The sea star Asterias amurensis is widely viewed as a severe“marine pest”because of its broad feeding habits.Over the past few decades,A.amurensis undergoes massive and sporadic population outbreaks worldwide,causing extensive economic and ecological losses to the local aquaculture industry and marine ecosystem.Understanding the genetic diversity and population structure of A.amurensis can provide vital information for resource management.By analyzing the polymorphism of the mitochondrial cytochrome C oxidase subunit I(COI)gene and ten simple sequence repeat(SSR)microsatellites markers,the genetic diversity and population structure of A.amurensis of four populations along the northern coast of China was uncovered.A total of 36 haplotypes were identified,and a main haplotype was found in four populations.The Qingdao(QD)population displayed the highest genetic diversity among all the populations.The AMOVA and pairwise F_(st)showed that there was small but statistically significant population differentiation among the four populations,especially between QD and Weihai(WH).Moreover,the principal component analysis(PCA)and admixture analysis showed that several individuals in Yantai(YT)and Dalian(DL)had little genetic association with other individuals.Overall,this study provided useful information of the genetic diversity and population structure of A.amurensis and will contribute to the resource management of A.amurensis in China.
基金supported by the Development Plan of Science and Technology Project of Jilin Province in China[20220508054RC].
文摘Peanut,with high oil content,has been a major oil and food crop globally.The compositions of the fatty acids are the common factors in determining the oil quality.In the present study,an F2 segregated population with 140 individuals derived from the cross of Weihua8(a cultivar)and 12L49(a line with high oleic acid concentration)was used to construct a genetic map and conduct QTL mapping analysis.A total of 103 polymorphic SSR primers were utilized for genotyping the RILs and finally generating the SSR loci.Within the 103 SSR loci,a genetic linkage map,covering a total length of 3592.35 cM of the whole peanut genome,was constructed.Based on the genetic map,sixteen QTLs located on nine linkage groups related to peanut fatty acids were finally identified.Among them,four QTLs were detected associated with various traits simultaneously,which showed genetic stability in relation to fatty acids of peanut.Except for the QTLs for oleic acid,linoleic acid,and linolenic acid,three novel QTLs for arachidic acid and behenic acid were also detected.These QTLs might be helpful for further fine mapping analysis and marker-assisted selection of fatty acids in peanut.
文摘Chloroplast simple sequence repeat (cpSSR) markers in Citrus were developed and successfully used to analyze chloroplast genome inheritance of Citrus somatic hybrids. Twenty-two previously reported cpSSR primer pairs from pine (Pinus thunbergii Parl.), rice (Otyza sativa L.) and tobacco (Nicotiana tabacum L.) were tested in Citrus, nine of which could amplify intensive PCR products by agarose gel electrophoresis. Chloroplast genome inheritance of Citrus somatic hybrids from nine fusions was then analyzed, and five of the nine pre-screened primer pairs showed polymorphisms by polyacrylamide gel electrophoresis. The results revealed the random inheritance nature of chloroplast genome in all analyzed Citrus somatic hybrids, which was in agreement with previous reports based on RFLP or CAPS analyses. It was also shown that cpSSR is a more efficient tool in chloroplast genome analyses of somatic hybrids in higher plants, compared with the conventional RFLP or CAPS analyses.
基金This paper was supported by Northeast Forestry University.
文摘Genetic relationships of eight species of genus Betula were evaluated using ISSR marks. A total of 236 loci were generated from 17 ISSR primers. Percentage of polymorphic bands (PPB) varied from 5.93 to 19.92. The highest and the lowest level of genetic differentiation were detected in B. ovalifolia and B. maximowicziana Regel respectively. In these eight species, genetic diversity of birch (HT) was 24.38 %, and the genetic variation (GST ) interspecies was accounting for 79.36% of total genetic variation. According to the cluster results of genetic distance, the eight species were classified into three groups as B. davurica, B. ovalifolia, B. platyphylla and B. pendula for one group; B. schmidtii, B. costata and B. ermanii Cham. var. communis for one group, and B. maximowicziana Regel for another group. The result of cluster is consistent with traditional morphological classification.
文摘Genetic diversity of 18 processing apple varieties and two fresh varieties were evaluated using 12 simple sequence repeats (SSR) primer pairs previously identified in Malus domestica Borkh. A total of 87 alleles in 10 loci were detected using 10 polymorphic SSR markers selected within the range of 5-14 alleles per locus. All the 20 varieties could be distinguished using two primer pairs and they were divided into four groups using cluster analysis. The genetic similarity (GS) of groups analyzed using cluster analysis varied from 0.14 to 0.83. High acid variety Avrolles separated from other varieties with GS less than 0.42. The second group contained Longfeng and Dolgo from Northeast of China, the inherited genes of Chinese crab apple. The five cider varieties with high tannin contents, namely, Dabinette, Frequin rouge, Kermerrien, M.Menard, and D.Coetligne were clustered into the third group. The fourth group was mainly composed of 12 juice and fresh varieties. Principal coordinate analysis (PCO) also divided all the varieties into four groups. Juice and fresh apple varieties, Longfeng and Dolgo were clustered together, respectively, using both the analyses. Both the analyses showed there was much difference between cider and juice varieties, cider and fresh varieties, as well as Chinese crab apple and western European crab apple, whereas juice varieties and fresh varieties had a similar genetic background. The genetic diversity and differentiation could be sufficiently reflected by combining the two analytical methods.