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1.
The present work was conducted to characterize the functionality of 257 watermelon EST–SSR primer pairs for their PCR amplification and polymorphisms. EST–SSR markers were tested on DNA sample panels of six watermelon cultigens and two related species of Citrullus lanatus var. citroides and Citrullus colocynthis based on agarose gel electrophoresis and high resolution melting (HRM) analysis. Successful PCRs were shown for 240 primer pairs (79%), and 173 primer pairs (67%) were polymorphic in a watermelon DNA sample panel on agarose gel electrophoresis. In addition, HRM analysis of 24 EST–SSR markers that were monomorphic on agarose gel separation identified an additional 19 polymorphic markers, indicating that HRM is an efficient tool for the rapid screening of sequence variations and allele discrimination. In the assessment of genetic relationships, six watermelon cultivars were closely related together (0.91–0.97) and demonstrated a narrow genetic base in the watermelon genetic pool. A high level of genetic dissimilarity (0.36–0.97) was shown between watermelon species and other related species. Marker transferability to melon species (Cucumis melo L.) was examined by cross-species PCR amplification and genetic diversity assessment in eight melon cultigens. Of the 257 EST–SSR primer pairs, 79 (32.9%) showed successful PCR amplification from melon DNA samples. A dendrogram of the genetic relationship based on 22 EST–SSR markers showed a clear classification of melon genotypes in accordance to fruit characteristics. The EST–SSR markers characterized in this study will contribute to diverse genomic investigations and breeding efforts, including comparative genome mapping, marker-assisted selection, and DNA fingerprinting for genetic diversity and cultivar identification in many cucurbit crops.  相似文献   

2.
This work reports the transferability and polymorphism of previously reported SSRs in 10 Prunus species. The availability of a large number of SSRs in the genus Prunus makes marker choice random, while preventing comparison of results in fingerprinting studies. The availability of SSR markers, polymorphic in a wide sample of Prunus species, would facilitate marker choice, while allowing the comparison of results. In this work, microsatellite markers useful for analyzing 10 different Prunus species (P. persica, P. dulcis, P. armeniaca, P. domestica, P. insititia, P. salicina, P. cerasifera, P. avium, P. cersus and P. mahaleb) were searched through screening SSRs previously reported to be conserved and/or polymorphic in more than one Prunus species. A selected group of 13 SSRs, transferable to the 10 species, was analyzed in terms of their usefulness for analyzing these species. The amplification range, polymorphism and variability detected by these loci are reported. The information provided will be useful for Prunus genetic studies as well as conservation and management of Prunus germplasm resources.  相似文献   

3.
We report on the development of novel simple sequence repeat (SSR) markers from publicly available Cucumis sativus expressed sequence tags (ESTs) and on their transferability among related species. In total, 533 di- to penta-type SSRs were identified from 6344 cucumber ESTs retrieved from GenBank. Identified SSRs mainly comprised of di- and tri-nucleotide repeats, of which AG and AAG motifs were much abundant. A total of 392 SSR-containing unigenes (non-redundant ESTs/consensus sequences) were suitable for primer design. From these, 35 primer pairs were designed as representative samples and 28 were usable markers. Twenty-six out of 28 usable markers revealed polymorphism among 21 cucumber accessions with 2–7 alleles detected (mean = 3.77) and their polymorphism information content (PIC) values ranged from 0.091 to 0.748 (mean = 0.388). The polymorphism observed herein partially arose from the null alleles which occurred at the multiple homoeoloci detected by the markers. Transferability of the 28 EST-SSR markers was investigated in four other cucurbits: melon, watermelon, pumpkin and gourd which showed frequency of 92.9%, 57.1%, 53.6% and 60.7%, respectively. The EST-SSR markers developed herein will complement the currently available genomic SSR markers and may be useful for genetic studies in cucumber and related species.  相似文献   

4.
In this study, the genetic diversity of four Iranian wild Prunus species including Prunus eleagnifolia, Prunus hauskenchtii, Prunus scoparia and Prunus lycioides were investigated using morphological, protein and DNA markers. DNA markers included nuclear and chloroplast SSRs and self-incompatibility (S) allele amplification. At the morphological level, leaf width showed significant differences between the four wild Prunus species. Concerning fruit and kernel characters, their values are relatively similar indicating the high degree of homoplasy described in Prunus. Nuclear SSR markers have been the most abundant markers with a higher polymorphism in comparison with morphological, protein and chloroplast SSR markers. Results also indicated the high variability present in the S locus. On the other hand, the correlation between the clustering based on DNA markers and protein were in general low. Dendogram performed using nuclear and chloroplast SSR indicated a more diffuse clustering between the wild almond species probably due to the natural introgression of genes observed in these wild almond species. Data from the analysis of the total protein seems to be more accurate to establish taxonomy relationships in these very close wild species.  相似文献   

5.
Eighty-one accessions representing apricot germplasm in Tunisia were collected from different areas of cultivation and fingerprinted using amplified fragment length polymorphism (AFLP) and microsatellites (SSR) markers. A total of 339 polymorphic markers were revealed using 5 AFLP primers combinations and 24 SSR loci. AFLP and SSR markers expressed a high level of polymorphism allowing the distinction of the accessions with an efficiency coefficient of discrimination of 100% for AFLP and 97% for SSR markers. Genetic diversity structure was assessed with AFLPs and SSRs markers separately then with combined matrix data by the help of hierarchical clustering elaborated using Wards method based on Nei and Li (1979) distances. Comparison of the obtained dendrograms revealed a phylogeographic structure into two major groups with significant conservation between the observed subgroups in relation with the geographic origin of the accessions. The relative efficiency of the markers in determining the genetic relationships among apricot accessions has been assessed and a combination of AFLPs and SSRs markers was the most effective. In addition, Mantel test based on genetic distances indicated highly significant correlation between AFLP-SSR data and each of the AFLP and SSR ones, with Pearson correlation values of r = 0.873 and r = 0.692, respectively, revealing the higher efficiency of the combination of both molecular techniques (AFLP and SSR) to estimate the levels of genetic variability among apricot germplasm.  相似文献   

6.
The ‘Genome database for Rosaceae (GDR)’ provides a large collection of expressed sequence tags (ESTs) harboring simple sequence repeats (SSRs) from several Rosaceae genera, including Rosa (rose). Primer pairs flanking SSR were designed for 312 unique Rosa ESTs based on GDR database. Eight rose (Rosa hybrida L.) genotypes were tested for PCR amplification, and 287 (92%) of the primer pairs generated allele-specific PCR bands that were readily scored. From 183 (63.7%) primer pairs that evidenced polymorphic alleles among the eight rose cultivars, 20 pairs evidencing EST sequence homology to known gene functions and high levels of polymorphism were selected and utilized for DNA fingerprinting and genetic diversity assessments of 47 rose hybrids. A total of 202 polymorphic bands were scored and generated unique fingerprints for each rose hybrid. The Nei–Li genetic similarity coefficients among 1081 pair-wise comparisons of 47 cultivars exhibited a broad range of genetic variations from 0.30 (‘Grand King’ and ‘Carnival’) to 0.99 (‘First Red’ and ‘Red Champ’). UPGMA cluster analysis divided 47 hybrids into five major groups and two sub-groups. The cross-species transferability of 273 EST-SSR primer pairs was evaluated using four genotypes of the strawberry, a genus member of the Rosaceae family. PCRs on the DNA samples of strawberry were successful for 165 primer pairs; among these, 123 pairs amplified 243 polymorphic bands. As surrogates of the marker transfer, the phenetic relationship among the four strawberry genotypes was evaluated. Genetic similarity coefficients varied from 0.78 (‘Maehyang’ and ‘Janghyee’) to 0.64 (‘Janghyee’ and ‘Pragana’). The results of cluster analysis showed that the three octaploid strawberry cultivars were quite similar, whereas the diploid ‘Pragana’ was related distantly at the genomic DNA level. The EST-SSR markers developed in the present study can be efficiently utilized for genetic diversity studies in Rosaceae.  相似文献   

7.
目前有多种发展微卫星标记(SSR)的方法,对基因组未测序的物种利用近缘物种引物进行跨物种扩增是一种简便方法。本研究利用马铃薯的640对SSR引物对茄子进行扩增,并利用获得的多态引物进行了12份茄子材料的聚类分析。结果表明:192对引物能够在茄子基因组DNA上扩增出清晰、稳定条带,引物通用率为30.05%;10对引物在随机选择的4份材料上有多态性,聚类分析结果表明类群与材料的来源、果实形态、颜色及青枯病抗性间没有相关趋势。  相似文献   

8.
RAPDs and SSRs were used to study the genetic diversity of Iranian almond cultivars and their relationship to important foreign cultivars and three related species. Eight unidentified almond Shahrodi cultivars and three wild almonds (Prunus communis, Prunus orientalis and Prunus scoparia) were also included. Of the primers tested, 42 (out of 80) RAPD and 18 (out of 26) SSR primers were selected for their reproducibility and high polymorphism. A total of 664 polymorphic RAPD bands were detected out of 729 bands. The number of presumed alleles revealed by the SSR analysis ranged from 3 to 10 alleles per locus with a mean value of 6.64 alleles per locus. Both techniques discriminated the genotypes very effectively, but only RAPDs were able to discriminate the cultivars Monagha and Sefied. Results demonstrated an extensive genetic variability within the tested cultivars as well as the value of SSR markers developed in peach for characterization of almond and related species of Prunus. Dice similarity coefficient was calculated for all pair wise comparisons and was used to construct a UPGMA dendrogram. For both markers a high similarity in dendrogram topologies was obtained although some differences were observed. All dendrograms, including that obtained by the combined use of both the marker data, depicted the phenetic relationships among the cultivars and species, depending upon their geographic region and/or pedigree information. Almond cultivars clustered with accession of P. communis showing their close relationship. P. orientalis and P. scoparia were clustered out of the rest of P. dulcis.  相似文献   

9.
Listada de Gandía is one of the most renowned Spanish eggplant (Solanum melongena L.) landraces. Assessing its genetic diversity and relationships, as well as devising tools for its identification, is of great relevance for the enhancement and protection of this landrace. Forty-two eggplant accessions, which included 25 Striped accessions, of which 19 were of the Listada type (six accessions of Listada de Gandía, eight of Other Spanish Listada, and five of Non-Spanish Listada) and six of the Other Non-Spanish Striped group, and 17 Non-Striped accessions were characterized with 17 genomic SSRs and 32 EST-SSRs. Genomic SSRs had, as a mean, a greater polymorphism and polymorphic information content (PIC) than EST-SSRs. Although Listada de Gandía proved to be genetically diverse, specific and universal alleles for two SSR markers were found for this landrace. All the Listada accessions cluster together in the multivariate PCoA and UPGMA phenograms performed, and are separated from the Other Non-Spanish Striped and Non-Striped accessions. Also, Listada de Gandía accessions were clearly differentiated from the Other Spanish Listada and Non-Spanish Listada accessions in these analyses. SSR markers revealed of great utility to obtain a specific fingerprint for the Listada de Gandía eggplant as well as to establish the uniqueness and distinctness of this landrace. This information will be very helpful for the enhancement and protection from imitation of Listada de Gandía, and contributes to support its potential recognition with a Protected Designation of Origin (PDO) status.  相似文献   

10.
A set of nine short sequence repeat (SSR) loci was used for the molecular characterization of 32 accessions of 15 chestnut trees selected in the field because of their putative resistance to the ink disease caused by Phytophthora spp. The goal of the present study was to determine the genetic identity of those selected European chestnut trees (Castanea sativa) or interspecific hybrids, considering that hybridization programs between European chestnut and Asiatic species (mainly Japanese chestnut, Castanea crenata) have been carried out in Galicia (Spain) since the early 20th century. The results showed that the analyzed SSR loci were useful to discriminate three Asiatic and the European species of Castanea. The joint information provided by a factorial correspondence analysis (FCA) and the presence of privative alleles allowed the putative molecular assignment of the selected plants to a certain identity. Most of them were determined as hybrids between C. crenata and C. sativa. The individuals coded C036 and C048 were assigned, with a high probability, to C. sativa due to their clustering with accessions of this species and because they had a number of privative alleles of this species. Only a few individuals could not be assigned to any particular genotype.  相似文献   

11.
Genetic diversity and relatedness of 23 yardlong bean (Vigna unguiculata spp. sesquipedalis) accessions and 7 accessions of a hybrid between cowpea (V. unguiculata spp. unguiculata) and yardlong bean (dwarf yardlong bean) in Thailand were estimated using morphological characters, simple sequence repeat (SSR) and inter-simple sequence repeat (ISSR) markers. In addition, two mungbean (Vignaradiata (L.) Wilczek) and two blackgram (Vigna mungo (L.) Hepper) accessions were also used as outgroup species for molecular analysis. Five morphological characters were diverse among most accessions. However, five groups of 2–3 accessions could not be distinguished from one another based on these morphological characters alone. Unweighted pair-group arithmetic average (UPGMA) analysis of these characters separated these 30 accessions into 2 major groups; the yardlong bean group and the dwarf yardlong bean group. Eleven of the sixteen SSR primers yielded clear SSRs, ten of which were polymorphic (90.91% polymorphism), detecting a total of 54 alleles with an average of 4.91 alleles per locus. These 10 polymorphic SSR markers successfully distinguished 28 yardlong bean and dwarf yardlong bean accessions. The polymorphic information content (PIC) among genotypes varied from 0.251 to 0.752 with an average of 0.597. Among the 16 ISSR primers used, a total of 312 ISSR fragments were amplified for these three Vigna species, revealing the polymorphism percentage of 91.03%. The average ISSR PIC value (0.197) with the range of 0.137–0.276 was lower than that of SSR. Nevertheless, the average marker index of this multilocus marker was 3.495, which was higher than that of SSR (0.669), owing to the differences in the effective multiplex ratio. In addition, Mantel test cophenetic correlation coefficient was higher for ISSR (0.566) than that of SSR (0.198). These results indicated higher efficiency of ISSR for estimating the levels of genetic diversity and relationships among yardlong beans and dwarf yardlong beans in this study. Pair-wise coefficients of SSR- and ISSR-based genetic similarity among all yardlong bean and dwarf yardlong bean accessions averaged 0.87 and 0.91, respectively, suggesting a narrow genetic base that emphasizes the need to broaden genetic diversity to ensure continued breeding success. Clustering of genotypes within groups was not similar when SSR and ISSR derived dendrograms from UPGMA analysis were compared. It appeared that ISSR was the most effective marker system in determining the genetic variability and relationships among yardlong bean and dwarf yardlong bean accessions and differentiating three Vigna species. In addition, ISSR was also most useful for variety identification since all 30 yardlong beans and dwarf yardlong bean accessions can be effectively distinguished by only four ISSR primers with the highest PIC values.  相似文献   

12.
Nine pairs of polymorphic chloroplast microsatellite primers were developed for Dendrobium officinale Kimura et Migo, an endangered herb. Levels of polymorphism were tested across a total of 55 individuals from four natural populations (12–15 individuals per population). Allele numbers varied from two to four per locus, while the number of haplotypes ranged from four to six per population. Transferability of the nine polymorphic chloroplast microsatellite primers was checked on an additional set of 51 Dendrobium individuals (belonging to 17 different species). Three markers could be transferable to all the species tested, while the remaining six markers successfully cross-amplified in most species tested. Moreover, polymorphism of the nine chloroplast microsatellite primers was tested across Dendrobium moniliforme (L.) Sw. and Dendrobium loddigesii Rolfe. All of them were polymorphic in D. moniliforme, while seven of which were polymorphic in D. loddigesii. These polymorphic chloroplast microsatellite primers developed for D. officinale will be a useful tool for the study of genetic diversity, population genetic structure, evolution of D. officinale and establishment of effective conservation strategies.  相似文献   

13.
In this study we evaluate the informativeness and efficiency of Amplified Fragment Length Polymorphism (AFLP), Sequence-Specific Amplified Polymorphism (S-SAP), Selectively Amplified Microsatellite Polymorphic Loci (SAMPL) and Simple Sequence Repeat (SSR) markers for genetic diversity, phylogenetic relationship among the Citrus species and mapping ability of the marker system. The SSR exhibited relatively higher level of polymorphism information content in terms of the expected heterozygosity, than that of the AFLPs, SSAPs and SAMPLs. For each marker system, average level of the discriminating potential was very close to the actual discriminating potential. Similarity matrices showed weak, yet significant correlations when Mantel's test was applied. The highest positive (0.72) correlation was found between the AFLP and SSAP markers. The SSR and SAMPL markers were poorly correlated. The dendrogram topology among the four marker systems had high similarity. Taken together, the SSAP and SAMPL were highly efficient in detecting genetic similarity in Citrus, while the SSR may be more useful for segregation studies and genome mapping in Citrus. The SSAP and SAMPL markers could be useful for Citrus genome mapping in combination with AFLP and SSR markers. To our knowledge, this was the first detail report of a comparison of performances among AFLP, SSR and retrotrasposon based molecular marker technique on a set of samples of Citrus. Our result provides guidance for future efficient use of these molecular methods in genetic analysis of Citrus sp. and its relatives.  相似文献   

14.
Here we characterized eight novel polymorphic SSR markers, developed from an enriched genomic library of garlic (Allium sativum L.). These SSRs produced a total of 64 alleles across 90 garlic accessions, with an average of 8 alleles per locus. Values for observed (HO) and expected (HE) heterozygosity ranged from 0.16 to 0.77 (mean = 0.44) and from 0.22 to 0.86 (mean = 0.65), respectively. Six loci deviated significantly (P < 0.05) from Hardy–Weinberg equilibrium (HWE). The averages of gene diversity and PIC values were 0.65 and 0.62, respectively. The mean genetic similarity coefficient was 0.4380, indicating that among garlic accessions existed wide genetic variation. Based on 64 alleles obtained by 8 SSRs, a phenogram was constructed to understand the relationships among the 90 accessions. These newly developed SSRs should prove very useful tools for genotypes identification, assessment of genetic diversity and population structure in garlic.  相似文献   

15.
White root rot (Dematophora necatrix (Mart.)) is a serious disease of apple (Malus domestica Borkh) in nurseries and orchards in India. In 2002 and 2003, field experiments were conducted to integrate soil solarization with native isolates of Azotobacter chrococcum and vesicular–arbuscular mycorrhizal fungi and observe its effect on the incidence of white root rot and growth of the saplings. Apple seeds coated with two native isolates of A. chrococcum (AZUHF1 and AZUHF2) were sown in plots inoculated with 4 native isolates of va-mycorrhiza, i.e. AMUHF1 (Glomus fesiculatum), AMUHF2 (Glomus macrocarpum), AMUHF3 (Glomus mosseae) and AMUHF4 (Gigaspora sp.) in 14 different combinations and these plots were solarized with transparent polyethylene mulch (25 μm thick) for 40 days in summer months. Soil solarization resulted around 9 °C higher temperature with average maximum temperature of 38–39 °C. Inoculation of saplings with AMUHF1 isolate of va-mycorrhiza and AZUHF1 isolate of A. chrococcum and then their planting in solarized soil was found most effective with no incidence of white root rot in comparison to 33.6–35.4% in control accompanied with 78–113% increase in shoot length and 81.6–84.3% increase in root length. Shoot and root length of the saplings was 9.6–10.6 and 9.2–16.0% higher, respectively, in solarized plots in comparison to sterilized plots.  相似文献   

16.
Rosa damascena Mill is the most important scented rose species cultivated for rose oil production. Rosa bourboniana L. (Edward rose), a related species, is popular on account of its longer blooming period and ease of propagation. With an aim to combine the oil quality of R. damascena and recurrent flowering habit of R. bourboniana, two cultivars (Jwala and Himroz) of R. damascena were crossed with R. bourboniana. The F1 hybrids obtained were evaluated using morphological, random amplified polymorphic DNA (RAPD) and microsatellite (SSR) markers. Twenty-two selected RAPD and three SSR primer pairs were utilized for hybrid identification. According to presence or absence of bands RAPD and SSR markers were classified into seven types of markers. The bands specific for the pollen parent and occurring in the hybrids were good markers to confirm the hybridity. The non-parental bands expressing uniquely in hybrids were effective in distinguishing the hybrids from each other. Cluster analysis, based on Jaccard's similarity coefficient using unweighted pair group method based on arithmetic mean (UPGMA), reliably discriminated the hybrids into two main clusters. These results indicate the practical usefulness of RAPD and SSR markers in hybrid identification in scented roses. The approach is advantageous for its rapidity and simplicity, for identification of hybrids at the juvenile stage. One of the studied morphological traits – prickle density, can also complement in the identification of interspecific hybrids between R. damscena (♀) and R. bourboniana (♂).  相似文献   

17.
Olive (Olea europaea L.) is an important fruit species in Italy and Mediterranean basin constituted by a wide germplasm with a large number of cultivars present in all the Mediterranean area. SSRs are becoming the markers of choice for variability studies in olives as they are simple to perform, transferable, hypervariable, highly polymorphic and show a high information content.Olive genetic diversity was studied using 16 SSR markers on 30 cultivars diffused in Southern-Italy. Resolving Power (RP) and Power of Discrimination (PD) were calculated to evaluate the efficiency of the SSR markers investigated in studies of cultivars fingerprinting. Based on their high efficiency, two SSR markers, UDO43 and DCA16 were chosen to set up an identification key to distinguish the entire set of cultivars, confirming the high biodiversity of the Southern-Italian olive germplasm and the suitability of SSR markers in studies of cultivar diagnosis.  相似文献   

18.
Characterization of microsatellites is extremely important for the development of molecular markers. Here, we present the detection and abundance of microsatellites or simple sequence repeats (SSRs) in UniGene sequences of Citrus sinensis. A total of 427 SSRs were mined in 8786 UniGene sequences downloaded from National Center for Biotechnology Information (NCBI). Depending on the repeat units, the length of SSRs ranged from 14 to 21 for mono-, 14 to 48 for di-, 18 to 48 for tri-, 24 to 40 for tetra- and 42 bp for hexa-nucleotide repeats. Average density of SSRs (1SSR/12.92 kb of 5518.71 kb sequences mined) suggests that only 4.43% of sequences contained SSRs. Di-nucleotide repeats were most frequent repeat type (49.41%) followed by tri-nucleotide repeats (41.45%). An attempt was made to design primer pairs for 427 identified SSRs but these were found only for 216 sequences. The positions of SSRs with respect to open reading frame (ORF) detected and annotation of sequences containing SSRs were also carried out to assign function to each of the sequences.  相似文献   

19.
A rich genetic diversity of coconut exists in farmer's fields, which represent valuable genetic resource for breeding. The study was conducted to assess the pattern of diversity in 102 coconut palms representing 10 landraces from 3 coconut-growing communities of India using 14 simple sequence repeat (SSR) markers. A total of 90 alleles were detected with an average of 6.42 alleles per locus and an average polymorphism information content of 0.61. Expected heterozygosity (He) was highest for the two tall landraces from Pallikkara community, while the least heterozygosity was observed for the dwarf coconut landraces from Vayalar community. Mean fixation index (FST) of 0.42 indicates a high level of population differentiation. A low gene flow (Nm) of 0.37 was observed. Based on molecular data, genetic similarities were calculated. The unweighted pair group method with arithmetic averages (UPGMA) cluster analysis grouped the landraces according to their geographical locations and breeding behaviour. The practical implications of this study in farmer participatory evaluation and conservation of coconut genetic resources are highlighted.  相似文献   

20.
Mulberry is a perennial and economically important plant that has traditionally been used for feeding the silkworm. Evaluating genetic relationship is important for long-term improvement in mulberry yield, quality and resistance, and for germplasm conservation and identification. Population structure and genetic diversity of 8 mulberry populations from different ecotypes in China were analyzed by ISSR markers. Twelve ISSR primers generated a total of 83 amplification products, of which 50 were polymorphic, revealing 60.24% polymorphism among 66 mulberry local varieties, the mean PIC value was 0.1469. The total heterozygosity (HT), heterozygosity within population (HS), diversity between populations (DST) were 0.1600, 0.0851 and 0.0749, respectively. The coefficient of population differentiation (GST) was 0.4683, indicating that the variations among populations and those within populations contributed 46.8% and 53.2% to the total heterozygosity, respectively. The gene flow (Nm) was 0.5678, suggesting that genetic drift between populations can caused local genetic differentiation and therefore, population divergence. The mean genetic similarity coefficient was 0.8456, genetic similarity coefficient among 8 mulberry populations ranged from 0.8441 to 0.9640, indicating that genetic diversity of different populations existed variation. A dendrogram of all 66 local varieties of mulberry based on the genetic similarity using ISSR markers was generated by UPGMA cluster method. In the dendrogram, most varieties from the same ecotype clustered together.  相似文献   

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