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BACKGROUND Costa Rica has a history of neglecting prevention, control and research of leishmaniasis, including limited understanding on Leishmania species causing human disease across the country and a complete lack of knowledge on the Leishmania RNA virus, described as a factor linked to the worsening and metastasis of leishmanial lesions. OBJECTIVES The aim of this work was to describe a case of cutaneous leishmaniasis by Leishmania (Viannia) guyanensis, bearing infection with Leishmaniavirus 1 (LRV1) in Costa Rica, raising the suspicion of imported parasites in the region. METHODS The Leishmania strain was previously identified by routine hsp70 polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in Costa Rica and subsequently characterised by isoenzyme electrophoresis and Sanger sequencing in Brazil. Screening for LRV1 was conducted with a dual RT-PCR approach and sequencing of the fragment obtained. FINDINGS Since 2016 Costa Rica performs Leishmania isolation and typing as part of its epidemiological surveillance activities. Amongst 113 strains typed until 2019, only one was characterised as a L. (V.) guyanensis, corresponding to the first confirmed report of this species in the country. Interestingly, the same strain tested positive for LRV1. Sequencing of the viral orf1 and 2, clustered this sample with other LRV1 genotypes of South American origin, from the Northeast of Brazil and French Guiana. MAIN CONCLUSION The unique characteristics of this finding raised the suspicion that it was not an autochthonous strain. Notwithstanding its presumed origin, this report points to the occurrence of said endosymbiont in Central American Leishmania strains. The possibility of its local dispersion represents one more challenge faced by regional health authorities in preventing and controlling leishmaniasis.
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The best linear unbiased prediction (BLUP), derived from the linear mixed model (LMM), has been popularly used to estimate animal and plant breeding values (BVs) for a few decades. Conventional BLUP has a constraint that BVs are estimated from the assumed covariance among unknown BVs, namely conventional BLUP assumes that its covariance matrix is a kK, in which k is a coefficient that leads to the minimum mean square error of the LMM, and K is a genetic relationship matrix. The uncertainty regarding the use of kK in conventional BLUP was recognized by past studies, but it has not been sufficiently investigated. This study was motivated to answer the following question: is it indeed reasonable to use a kK in conventional BLUP? The mathematical investigation concluded: (i) the use of a kK in conventional BLUP biases the estimated BVs, and (ii) the objective BLUP, mathematically derived from the LMM, has the same representation as the least squares.
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Objective: To make a distinction between Ludisia discolor and its relatives genus in molecular level, SCoT markers were employed to assess the genetic relationship and construct the DNA fingerprint. Methods: Orthogonal design method were carried out to optimize the suitable SCoT-PCR reaction system based on five factors. The optimum annealing temperature and SCoT primers were also screened. The 12 germplasm resources were used as materials, the screened primers were selected to analyze the genetic relationship of 12 materials. POPGENE was used to calculate the genetic diversity, NTSYS was performed to analyze cluster, and DNA map was constructed. Results: The optimized SCoT-PCR reaction system was constructed and a total of 12 rich bands were screened out as the primers of SCoT molecular marker with polymorphism ratio of 98.98%. According to Nei's genetic similarity coefficient, a total of 12 materials were divided into three cluster when coefficient was 0.45. Goodyera schlechtendaliana was in category I with seven L. discolor lines, indicating that these samples had close relationship. In category II, there were three samples came from Anoectochilus roxburghii. Moreover, a green L. discolor sample was alone clustered into category III. The DNA fingerprint map by the SC8 primer could identify the 12 materials. Conclusion: There are rich genetic diversities in 12 samples of L. discolor and its relatives genus, and the construction of DNA fingerprint map provides a theoretical basis for the identification of L. discolor and its relatives genus, which were tested in this study.
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Objective:To explore genetic relationship and population structure of Turpinia arguta in six locations of Jiangxi province by inter-simple sequence repeat （ISSR） molecular marker technique， and to provide theoretical basis for the protection and utilization of this medicinal material resource. Method:A total of 22 samples from six locations in four counties in Jiangxi province were collected， and genomic DNA was extracted by kit method. Polymerase chain reaction （PCR） amplification was performed using sixty-four universal ISSR molecular marker primers， and the products were detected with polyacrylamide gel electrophoresis （PAGE）. NTsys 2.10e software was selected to calculate the genetic similarity coefficient by unweighted pair group method with arithmetic mean （UPGMA） and cluster analysis. Population genetic structure was analyzed by Structure 2.1 software. Result:A total of forty-eight ISSR primers were amplified to obtain the product， the percent of polymorphic bands ranged from 45.45% to 100%. UPGMA cluster analysis showed that these plant individuals could not be clustered according to their respective executive locations. Analysis of population genetic structure showed that 22 samples of T. arguta could be divided into three populations. Conclusion:There is gene exchange among the populations of T. arguta in Jiangxi province， and it can affect the genetic structure of germplasm resources from different geographical sources.
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Objective: To identify the genetic relationship of cultivated and wild Atractylodes and its closely related species by using the Internal Transcribed Spacer 2(ITS2)barcode,in order to explore the cultivation origin of A. coreana from Northeast China. Method: Genomic DNAs were extracted from 40 samples of Atractylodes and its closely related species from different cultivated habitats,and 7 samples of wild A. coreana. were also extracted. The ITS2 sequences of these samples were amplified, and bidirectional sequencing was conducted by polymerase chain reaction(PCR). Totally 47 ITS2 sequences were aligned by using MEGA 5.0,5.8S and 28S sequences were removed to obtain the complete ITS2 sequence and build neighbor-joining (NJ) tree. Result: The lengths of ITS2 sequences of all samples were 232 bp. The NJ tree and the secondary structures of ITS2 showed that various varieties could be distinguished obviously except A. chinesis and A. coreana,which showed a good monophyly. The NJ tree showed that cultivated and wild A. coreana can also get together very well. Conclusion: As a DNA barcode,ITS2 sequences can be used to stably and accurately distinguish various varieties of Atractylodes. The relationship between A. chinesis and A. coreana is very close. A. coreana can be considered as a variant of A. coreana in North China. It is recommended to incorporate A. coreana into A. chinesis. The large-scale cultivation of A. coreana may originate from local wild population in Liaoning province,and the provenance may come from Xiuyan and other places in Liaoning province.
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Objective: Genetic reationships betwen Swertia mileensis and its relatives have been researched using Fourier transform infrared (FTIR) spectroscopy combined with chemometrics methods in order to provide a theoretical basis for the development and utilization of medicinal plant resources of genus Swertia. Methods: Infrared spectrum information of Swertia mileensis, Swertia cincta, Halenia elliptica, Swertiaion nervosa, Swertia punicea, and Swertia binchuanennsis was collected and used in this study. Original infrared spectra data were pretreated by these methods including automatic baseline correction, automatic smoothing, ordinate normalization, multiplicative scatter correction and second derivative, and analyzed by principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA) and hierarchical cluster analysis (HCA). Results: Absorption area of relationship between Swertia mileensis and its relatives ranged from 900-400 cm-1, 1 310-900 cm-1, 1 500-1 310 cm-1, 1 800-1 500 cm-1, 2 800-3 000 cm-1, and 3 000-3 500 cm-1. Absorption peaks of the second derivative of fingerprint region in 400 to 1 000 cm-1 were distinct, and the absorption peaks as well as peak numbers, intensities and patterns among species were quite different. Analysis of preprocessed IR data showed that PCA analysis of six Swertia species was superior to PLS-DA analysis. The results of HCA analysis showed that Swertia mileensis was closely related to Swertia cincta and Swertia nervosa. Conclusion: FTIR spectroscopy combined with chemometrics method could discriminate different species of genus Swertia and display the closely genetic relationship of Swertia mileensis and its relatives, furthermore, this research would provide a fast and effective method for studying genetic relationship of genus Swertia.
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Objective: To screen and evaluate DNA barcoding of Amomun tsao-ko populations in Yunnan. Methods: ITS, psbA-trnH, matK, rbcL, and ycf1 sequences were screened and evaluated using A. tsao-ko as samples. The samples of A. tsao-ko population were amplified and sequenced. The sequences were spliced with Genestar, and then processed with Mega for data processing. And A. tsao-ko diversity and identification were analyzed and discussed. Results: The length of the amplified fragments of primers ITS5 and ITS4 was approximately 520 bp; The length of the amplified fragments of the primers rbcLa-F and rbcLa-R was approximately 498 bp; The length of the amplified fragments of the primers ycf1-bF and ycf1-bR was approximately 800 bp; The length of the amplified fragments of the primers psbA-trnH-1F and psbA-trnH-1R was approximately 400 bp; The length of the amplified fragments of the primers matK-2F and matK-2R was approximately 470 bp. The success rate of amplification and sequencing was high, and most of the results were available. By analyzing the amplification results of ITS, psbA-trnH, matK and ycf1 sequences of A. tsao-ko, A. tsao-ko and other Amomum genus plants can be clearly distinguished; All samples of the ITS sequence were divided into MG5 white flower A. tsao-ko population and other populations; All samples of the psbA-trnH sequence were divided into MG5 white flower A. tsao-ko population, MG6 yellow flower A. tsao-ko population and other populations; All samples of the matK sequence were divided into MG6 A. tsao-ko population and other populations. The MG5 white flower A. tsao-ko sample failed to be amplified; All samples of the ycf1 sequence were divided into the MG6 yellow flower A. tsao-ko population and other populations, and the MG5 white flower A. tsao-ko population was clustered with the other 22 A. tsao-ko populations; The amplification of rbcL sequence was consistent for all samples. Conclusion: The ITS, matK, psbA-trnH and ycf1 sequences can accurately distinguish A. tsao-ko from other plants of Amomum genus; The sequence site variations were found in matK, psbA-trnH and ycf1 sequences of MG6. This research has contributed to the selection and breeding of A. tsao-ko varieties. ITS and psbA-trnHsequences can distinguish yellow flower and white flower of A. tsao-ko; There is no variation in the rbcL sequence of all samples of white and yellow flowers of A. tsao-ko, and Amomum tsao-ko and other plants of Amomum genus cannot be identified with the rbcL sequence, which can be discarded.
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Objective To detect the genetic relationship among nine medicinal species of Dipsacus in China. Methods The polymorphic bands were detected by three labeling methods (ISSR, SCoT, and SRAP). The genetic distances were calculated by TREECONW software and the systematic diagram of genetic relationship was clustered by UPGMA method. Results The percentage of polymorphism by ISSR, SCoT and SRAP markers showed little difference with value at 90.4%, 88.5%, and 88.2%, respectively, which indicated that the genetic polymorphism of the tested materials was very rich. The genetic distance between Dipsacus chinensis and D. japonicus was the largest, which indicated their genetic relationship was the most distant. Nine medicinal species of Dipsacus were all divided into three groups by three markers, that D. chinensi and D. lijiangensis, D. asperoides and D. japonicas were respectively clustered into one group, D. asperoides var. omiensis was alone clustered, the other four species were clustered into one group. The clustering results labeled by ISSR and SRAP were basically the same with a slight difference between D. daliensis and D. asperoides. Conclusion The clustering results by there markers was between well consistent with the classical classification, which confirmed that molecular markers can be used as one of the effective methods to reveal the genetic relationship among medicinal species of Dipsacus.
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Objective: To analyze the genetic diversity and relationship of Epimedium acuminatum from different habitats in Guizhou Province. Methods: PopGene 32 software and NTsys2.10e software was used to analyze the genetic diversity and phylogenetic relationship of five different habitats in Guizhou Province, and phylogenetic tree was constructed according to the UPGMA method. Results: A total of 13 polymorphic and clear bands were screened from 100 random primers showed that amplified 211 bands, of which 205 were polymorphic from the level of species, the percentage of polymorphic bands (PPB) was 97.16%. The Shannon’s information index (I) was 0.455 7; Nei’s gene diversity index (He) was 0.297 3; The effective number (Ne) of alleles was 1.490 2; The total genetic diversity (Ht) of five populations was 0.297 3, while the population genetic diversity within the group (Hs) was 0.207 5, indicated that the genetic variation mainly existed within populations, genetic differentiation within population than that of population between. The population genetic distance clustering was built by UPGMA. The results showed that five populations were divided into two branches, three populations from Anshun, Huaxi, and Gaopo clustered into one branch, and the other two populations from Longli and Leishan populations clustered into one branch. Conclusion: ISSR molecular marker technique can be used to analyze the genetic diversity and phylogenetic relationship of Epimedium acuminatum from different habitats in Guizhou Province.
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Objective To evaluate the genetic diversity and phylogenetic relationships of Amomun tsao-ko populations in Yunnan. Methods Seven pairs of microsatellite (SSR) primers were used to analyze 24 A. tsao-ko populations; First, GenALEx was used to calculate genetic diversity parameters, PCoA and AMOVA analysis was carried out; NTsys software was then used to draw population clusters map; And finally, the Structure software was used to calculate the best K value. Results The average of Shannon’s diversity index (H) of the 24 A. tsao-ko populations was 0.49, the average of heterozygosity (He) was 0.32, the genetic differentiation coefficient (Fst) was 0.090, and the gene flow (Nm) was 2.930. Eighty-one percent of the genetic differentiation among the 24 populations of A. tsao-ko existed within the population, and only 19% existed among the populations. The genetic identity (I) of the 23 A. tsao-ko populations of yellow flowers was 0.631 8-0.982 4. The genetic distance (D) was in the range of 0.017 7- 0.459 2, while the consistency degree of the A. tsao-ko population of white flower (MG5) and 23 other yellow flowers was 0.369 7-0.609 0. However, cluster analysis showed that A. tsao-ko population of the white flowers and yellow flowers were clearly separated at the genetic distance of 0.49. Structure clustering showed 209 A. tsao-ko resources can be divided into four groups when K value was 4. Conclusion The genetic diversity of A. tsao-ko populations of yellow flowers of Yunnan is higher on average, and the genetic variation is mainly found in population rather than among populations. According to the genotypes, A. tsao-ko of yellow flower and white flower are clearly divided into two categories, and the genetic distance is very far; and the yellow flower of A. tsao-ko is roughly divided into four groups.
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OBJECTIVE: To obtain the genetic information of 181 domestic and foreign licorice samples by determining the internal transcribed spacer sequence 2 (ITS2) in order to clarify their phylogenetic relationships and differentiate the medicinal licorice species from the non-medicinal ones. METHODS: Genomic DNA was first extracted from licorice samples of different origins and habitats. Then, the ITS2 sequences were amplified using PCR technique. Next, the ITS2 sequences were subjected to sequence analyses and neighbor-joining(NJ) tree analysis. Finally, the analytical method based on ITS2 DNA barcodes was established for the licorice species discrimination. The method was then applied to the phylogenetic analysis among the suspected domestic mutants, foreign licorice samples and domestic medicinal licorices, in addition to the discriminations of the medicinal and non-medicinal licorices. RESULTS: The medicinal licorice could be explicitly separated from the two commonly encountered non-medicinal licorice species either by using ITS2 sequence analysis or NJ tree analysis; and the suspected domestic mutants and foreign licorice samples converged with the medicinal licorice to form one monophyletic branch in the NJ tree analysis, which indicated unambiguously conspecifics. CONCLUSION: This study establishes a method for discrimination of medicinal and non-medicinal licorices based on ITS2 barcodes; and by the advantage of this method, the conspecific relationships among the suspected domestic mutants, foreign licorice samples and Chinese medicinal licorice are clarified. Thus a theoretical reference to the expansion of medicinal licorice resources and assurance of the safety and efficacy of the clinical licorice medications are provided.
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Background: Availability of related rice species is critical for rice breeding and improvement. Two distinct species of domesticated rice exist in the genus Oryza: Oryza sativa (Asian rice) and Oryza glaberrima (African rice). New rice for Africa (NERICA) is derived from interspecific crosses between these two species. Molecular profiling of these germplasms is important for both genetics and breeding studies. We used 30 polymorphic SSR markers to assess the genetic diversity and molecular fingerprints of 53 rice genotypes of O. sativa, O. glaberrima, and NERICA. Results: In total, 180 alleles were detected. Average polymorphism information content and Shannon's information index were 0.638 and 1.390, respectively. Population structure and neighbor-joining phylogenetic tree revealed that 53 genotypes grouped into three distinct subpopulations conforming to the original three groups, except three varieties (IR66417, WAB450-4, MZCD74), and that NERICA showed a smaller genetic distance from O. sativa genotypes (0.774) than from O. glaberrima genotypes (0.889). A molecular fingerprint map of the 53 accessions was constructed with a novel encoding method based on the SSR polymorphic alleles. Ten specific SSR markers displayed different allelic profiles between the O. glaberrima and O. sativa genotypes. Conclusions: Genetic diversity studies revealed that 50 rice types were clustered into different subpopulations whereas three genotypes were admixtures. Molecular fingerprinting and 10 specific markers were obtained to identify the 53 rice genotypes. These results can facilitate the potential utilization of sibling species in rice breeding and molecular classification of O. sativa and O. glaberrima germplasms.
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Oryza/genetics , Genetic Variation , Polymorphism, Genetic , Breeding , DNA Fingerprinting , Microsatellite Repeats , GenotypeABSTRACT
Background: Genetic diversity studies are important for the selection of parents with a greater combination capacity that, when crossed, increase the chances of obtaining superior genotypes. Thus, 26 polymorphic simple sequence repeat (SSR) primers were used to assess the genetic diversity of 140 individual samples from 12 diploid sugar beet pollinators (pollen parents) and two cytoplasmic male sterile (cms) lines (seed parents). Eight pollinators originated from three research centers in the United States Department of Agriculture, while four pollinators and cms lines were from the Institute of Field and Vegetable Crops, Novi Sad, Serbia. Results: In total, 129 alleles were obtained, with a mean of 3.2 alleles per SSR marker. The observed heterozygosity ranged from 0.00 to 0.87 (mean = 0.30). Expected heterozygosity and Shannon's information index were the lowest for marker BQ590934 and the highest for markers SB15s and FDSB502s; the same markers were the most informative, with PIC values of 0.70 and 0.69, respectively. Three private alleles were found in pollinator EL0204; two in pollinator C51; and one in pollinators NS1, FC221, and C93035. Molecular variance showed that 77.34% of the total genetic variation was attributed to intrapopulation variability. Cluster and correspondence analysis grouped sugar beet pollinators according to the breeding centers, with few exceptions, which indicate that certain amount of germplasm was shared, although centers had their own breeding programs. Conclusions: The results indicate that this approach can improve the selection of pollinators as suitable parental components and could further be applied in sugar beet breeding programs.
Subject(s)
Pollen/genetics , Genetic Variation , Beta vulgaris/genetics , Polymorphism, Genetic , Seeds/genetics , Selection, Genetic , Breeding , Polymerase Chain Reaction , DNA, Plant/genetics , Microsatellite Repeats , Pollination , GenotypeABSTRACT
Teak (Tectona grandis L.f.), a paragon timber tree of tropical deciduous forests of Central and Peninsular India, is highly prized for its wood colour, decorative grains, durability and lightness. An experiment was carried out to compare the genetic variation detected and genetic relationships inferred in five teak populations via 10 genomic DNA samples per population each of either single seed or bulk of 3- or 5- seeds with the help of ISSR markers. The genomic DNA of single seed exhibited higher number of polymorphic loci, per cent polymorphism, nei’s genetic diversity and shannon Information Index than the bulk genomic DNA of 3- or 5- seeds. The bulking of genomic DNA of 3- and 5- seeds using Nei’s genetic distance coefficient revealed similar genetic relationships, which were at variance with those in single seed treatment. Mantel’s correlation test among the genetic distance matrices of single seed sampling, 3-seed bulk and 5-seed bulk sampling also confirmed the trend. Since the bulking of genomic DNA did not generate compatible estimates of diversity parameters and genetic relationship of five populations from its single seed sampling, we recommend strict guarding of identities of genotypes within the collected samples for obtaining precise estimates and drawing accurate conclusions about the genetic diversity and clustering of populations.
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Objective: To study the genetic relationship and genetic diversity of Ferula syreitschikowii germplasm resources in Xinjiang province. Methods: A total of 96 F. syreitschikowii germplasm resources of Xinjiang province were used as experimental materials. Fifteen primers selected from 33 ISSR primers could obtain high polymorphism and reproducibility bands for ISSR molecular marker analysis. Results: Total by 292 DNA bands were amplified including 289 polymarphic bands, counting for 99.01%. Genetic similarity analysis showed F. syreitschikowii germplasm resources of Xinjiang province with high genetic diversity. Through the statistical software analysis, the average number of effective alleles was 1.725 6, the average Nei's genetic diversity index was 0.4048, the average Shannon's information index was 0.587 9, and the genetic similarity coefficients among tested clones ranged from 0.500 0 to 0.828 7. These 96 germplasm resources were divided into two groups and 13 subgroups by UPGMA analysis, which could distinguish the germplasm resources from different sources. Conclusion: From the molecular level, it reveals the relationship between the geographical distribution of F. syreitschikowii and the germplasm resources and higher genetic diversity of germplasm resources, which provids basis for identification of F. syreitschikowii varieties.
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Objective: The genetic relationship between Paris polyphylla var. yunnanensis and its relatives has been researched using Fourier transform infrared (FT-IR) spectroscopy combined with chemometrics methods in order to provide a theoretical basis for the development and utilization of medicinal plant resources of genus Paris L. Methods: The infrared spectrum information of 50 samples of P. polyphylla var. yunnanensis, P. polyphylla var. alba, P. mairei, P. vietnamensis, and P. axialis var. axialis was collected. The original infrared spectra data were pretreated by automatic baseline correction, automatic smoothing, ordinate normalization, multiplicative scatter correction and second derivative, and analyzed by principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA) and hierarchical cluster analysis (HCA). Results: The common peaks of 1 653, 1 156, 1 082, 1 021, 925, 851, 759, 572 and 524 cm-1 in original spectra data of 50 samples might be relative to the contents of flavonoids, starches and glycosides. The absorption peaks of 1 535 and 1 369 cm-1 belonged to P. mairei and P. axialis var. axialis, respectively which could be distinguished from other three species. By PCA and PLS-DA, the former one which could accurately distinguish five species of wild genus Paris L. presented a better classification result than the latter. HCA and vector included angle cosine analysis could reflect the genetic relationship of P. polyphylla var. yunnanensis and its wild relatives. P. polyphylla var. alba and P. vietnamensis had closed relationship with P. polyphylla var. yunnanensis while P. mairei and P. axialis var. axialis were relative far. Conclusion: FT-IR spectroscopy combined with chemometrics methods can distinguish different species of genus Paris L. and display the genetic relationship between P. polyphylla var. yunnanensis and its wild relatives, clearly. Furthermore, it could provide a fast and effective method for the study of plant genetic relationships and a theoretical basis for the development and utilization of medicinal plant resources of genus Paris L.
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The genetic diversity and genetic relationship among four medicinal species of Coptis were detected by the approach of sequence-related amplified polymorphism (SCoT). The associated genetic parameters were calculated by POPGENE1.31. The systematic diagram of genetic relationship were clustered by TREECONW. The results showed that a total of 434 bands were produced by using 28 primers, of which 430 were polymorphic loci. There was a high level of genetic diversity among species (PPB=99.1%,Na=1.990 6,Ne=1.329 3,H=0.212 2,I=0.337 8). However, genetic diversity was lower within species, the average of genetic parameters wasPPB=16.8%,Na=1.168 2, Ne=1.073 0,H=0.043 7,I=0.067 7. The Nei's genetic differentiation coefficient was 0.794 0, that indicated that most of the genetic variation existed among species. By clustering analysis, different individuals gathered in the same group. The results confirmed that SCoT marker can be used as one of the effective methods to reveal the genetic diversity and relationship among medicinal species of Coptis.
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Objective: In order to understand the genetic relationship and genetic diversity of peony (Paeonia suffruticosa) in Hunan province, the DNA fingerprints of 47 peony germplasm materials of Hunan province were studied. Methods: Seven primers selected from 100 ISSR primers could obtain high polymorphism and reproducibility bands using ISSR markers. Results: Total 77 DNA bands were amplified including 67 polymarphic bands, counting for 87.01%. Genetic similarity analysis showed that Hunan peony germplasm resourses with high genetic diversity. Through the computer software analysis, peony variety tested the average effective number of alleles was 1.395 4, the average Nei's genetic diversity index is 0.248 0, the average Shannon's information index was 0.385 9; Between each type of the similarity coefficient of Jaccard was 0.532 5-0.961 0, with an average of 0.751 5, which was a sign of close genetic relationship between the materials. These 47 germplasm resourses were divided into two groups and three subgroups by UPGMA analysis, which could distinguish the varieties from different sources. Conclusion: It reveals from the molecular level of Hunan local peony varieties, genetic relationship, and genetic diversity so as to provides the theoretical basis for the varieties breeding worke of heat and humid resistance of peony.
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Objective To investigate the genetic relationships of Astragalus membranaceus and Codonopsis pilosula from the different cultivars (varieties). Methods Twenty-five samples of A. membranaceus and seventeen samples of C. Pilosula were amplified by ISSR-PCR. Genetic diversity and genetic distance were analyzed by Popgen32. UPGMA dendrogram relationship was clustered by NTSYS. Results Totally 62 and 100 loci were detected respectively from A. membranaceus and C. pilosula. All percentages of polymorphic loci (PPL) were 100%. Shannon’s information indexes (I) were 0.537 6 and 0.472 7. Nei’s genetic diversity indexes (H) were 0.361 3 and 0.307 4. A. membranaceus was divided into two groups in genetic distance 0.59, and C. pilosula was alike in 0.50. Conclusion Different cultivars (varieties) of A. membranaceus and C. pilosula had rich genetic diversities among species, and had large genetic differences.
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Background & objectives: PFGE, rep-PCR, and MLST are widely used to identify related bacterial isolates and determine epidemiologic associations during outbreaks. This study was performed to compare the ability of repetitive sequence-based PCR (rep-PCR) and pulsed-field gel electrophoresis (PFGE) to determine the genetic relationships among Escherichia coli isolates assigned to various sequence types (STs) by two multilocus sequence typing (MLST) schemes. Methods: A total of 41 extended-spectrum β-lactamase- (ESBL-) and/or AmpC β-lactamase-producing E. coli clinical isolates were included in this study. MLST experiments were performed following the Achtman’s MLST scheme and the Whittam’s MLST scheme, respectively. Rep-PCR experiments were performed using the DiversiLab system. PFGE experiments were also performed. Results: A comparison of the two MLST methods demonstrated that these two schemes yielded compatible results. PFGE correctly segregated E. coli isolates belonging to different STs as different types, but did not group E. coli isolates belonging to the same ST in the same group. Rep-PCR accurately grouped E. coli isolates belonging to the same ST together, but this method demonstrated limited ability to discriminate between E. coli isolates belonging to different STs. Interpretation & conclusions: These results suggest that PFGE would be more effective when investigating outbreaks in a limited space, such as a specialty hospital or an intensive care unit, whereas rep-PCR should be used for nationwide or worldwide epidemiology studies.