Genetic diversity in Puccinia striiformis Westend. f.sp. tritici revealed by pathogen genome-specific repetitive sequence

1998 ◽  
Vol 76 (4) ◽  
pp. 587-595 ◽  
Author(s):  
Wei-xing Shan ◽  
Shou-yi Chen ◽  
Zhen-sheng Kang ◽  
Li-ren Wu ◽  
Zhen-qi Li
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Dna Fingerprinting ◽  
Puccinia Striiformis ◽  
Phenotypic Diversity ◽  
Molecular Evidence ◽  
Polymorphism Analysis ◽  
Dna Fingerprints ◽  
High Level ◽  
Virulence Variation

DNA fingerprinting was used to examine genetic variation in populations of Puccinia striiformis Westend. f.sp. tritici, an obligate fungus that causes wheat stripe rust, using as a probe a moderately repetitive DNA sequence PSR331 that shows species specificity in the genome of this pathogen. One hundred and sixty isolates sampled from six provinces throughout China were examined for genetic variation over 26 putative genetic loci defined by PSR331 and the restriction enzyme BglII. Because of the dikaryotic nature of this fungus, DNA fingerprints can not differentiate heterozygotes from homozygotes. We refer to the PSR DNA fingerprints as phenotypes rather than genotypes. Phenotypic diversity analysis revealed a high level of genetic variation. A total of 97 phenotypes was detected among 160 isolates. Phenotypic diversity varied among regions, ranging from 0.3742 in Shaanxi to 0.9380 in Gansu, as calculated with the normalized Shannon's index. Genetic subdivision analysis revealed a low level of genetic differentiation (GST = 0.0084) among regions (Gansu, Henan, Shaanxi, Sichuan, and Yunnan provinces) as well as within regions (Gansu and Sichuan provinces). This, together with the detection of the same phenotypes among regions, provided the molecular evidence for gene flow in P. striiformis f.sp. tritici. The results support conclusions from virulence surveys that Tianshui of southern Gansu is probably the most important "hotspot" area with respect to the potential to generate and maintain virulence variation. DNA polymorphism analysis also detected potential hotspot areas in addition to southern Gansu. This may result in more difficulties in management of genetic variation and thus the potential virulence variation in P. striiformis f.sp. tritici as well as providing opportunities for searching disease resistance factors.Key words: genetic diversity, Puccinia striiformis, DNA fingerprinting, virulence variation.

scholarly journals Genetic Diversity and Evolutionary Relationships of Chinese Pepper Based on nrDNA Markers

Forests ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 543
Author(s):  
Shijing Feng ◽  
Jinshuang Niu ◽  
Zhenshan Liu ◽  
Lu Tian ◽  
Xiangyuan Wang ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Genetic System ◽  
Haplotype Network ◽  
Evolutionary Relationships ◽  
Genetic Profile ◽  
Coding Region ◽  
Demographic Trends ◽  
Evolutionary Forces ◽  
High Level

Chinese pepper, referring to Zanthoxylum bungeanum Maxim. and Zanthoxylum armatum DC. species, is an important spice crop that has long attracted people’s interest due to its extensive application in Asian cuisine to improve taste. Numerous cultivars have been developed during the long history of domestication and cultivation. However, little to no information is available on the genetic diversity and evolutionary relationships of Chinese pepper cultivars and their historical diversification has not been clarified. Herein, we sequenced two nrDNA non-coding region markers, the external transcribed spacer (ETS) and the internal transcribed spacer 2 (ITS2), to assess genetic diversity and phylogenetic relationships among 39 cultivated and wild populations of Chinese pepper from eight provinces and to address the question of ancient demographic trends which were probably influenced by changing climate during evolutionary history. In total, 31 haplotypes were identified based on 101 polymorphism sites. Our results revealed relatively high level of genetic variation despite long-term cultivation of this crop. AMOVA revealed that genetic variation existed predominantly within provinces rather than among provinces. The genetic structure result based on haplotype network analysis largely reflected historical records, which suggested a Gansu origin for Chinese pepper and an ancient west-to-east spread of Chinese pepper circulating in China. We also provided evidence that changing Pleistocene climates had shaped the demographic trends of Chinese pepper. Taken together, our findings not only suggest that Chinese pepper is a dynamic genetic system that responds to evolutionary forces, but it also provides a fundamental genetic profile for the conservation and responsible exploitation of the extant germplasm of Chinese pepper and for improving the genetic basis for breeding the cultivars.

High Levels of Genetic Variability in an Isolated Colony of Rock-wallabies (Petrogale assimilis): Evidence from Three Classes of Molecular Markers

1997 ◽  
Vol 45 (2) ◽  
pp. 199 ◽  
Author(s):  
Peter B. S. Spencer ◽  
Mark Adams ◽  
Helene Marsh ◽  
David J. Miller ◽  
Mark D. B. Eldridge
Keyword(s):  
Genetic Variation ◽  
Molecular Markers ◽  
Genetic Variability ◽  
Mating Systems ◽  
Selective Pressure ◽  
Multiple Mating ◽  
Dna Fingerprints ◽  
Average Heterozygosity ◽  
Low Levels ◽  
High Level

Estimates of genetic variation for a small (Ne = 39) colony of allied rock-wallabies (Petrogale assimilis) were calculated with three different categories of molecular marker. Average heterozygosity was estimated at 3·8% for allozymes, 47·3% for multilocus ‘DNA fingerprints’ and 85·5% for microsatellite markers. Overall these values indicate that this small isolated colony of rock-wallabies maintains a high level of genetic variation despite its relative isolation and the apparently low levels of migration between colonies. It is likely that mechanisms exist (such as kin avoidance, multiple mating systems, high and variable selective pressure in extreme and fluctuating environmental conditions) that promote the maintenance of high levels of genetic variation in isolated colonies of P. assimilis. These mechanisms are discussed in the context of the results obtained from the molecular markers.

Genetic diversity in Elymus caninus as revealed by isozyme, RAPD, and microsatellite markers

Genome ◽  
1999 ◽  
Vol 42 (3) ◽  
pp. 420-431 ◽  
Author(s):  
Gen-Lou Sun ◽  
Oscar Díaz ◽  
Björn Salomon ◽  
Roland von Bothmer
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Microsatellite Markers ◽  
Correlation Coefficients ◽  
Geographic Isolation ◽  
Elymus Caninus ◽  
Distance Matrices ◽  
High Level ◽  
Mantel’S Test ◽  
Similarity Matrices

Genetic diversity of 33 Elymus caninus accessions was investigated using isozyme, RAPD, and microsatellite markers. The three assays differed in the amount of polymorphism detected. Microsatellites detected the highest polymorphism. Six microsatellite primer pairs generated a total of 74 polymorphic bands (alleles), with an average of 15.7 bands per primer pair. Three genetic similarity matrices were estimated based on band presence or absence. Genetic diversity trees (dendrograms) were derived from each marker technique, and compared using Mantel's test. The correlation coefficients were 0.204, 0.267, and 0.164 between isozyme and RAPD distance matrices, RAPD and microsatellite distance matrices, and between isozyme and microsatellite distance matrices, respectively. The three methodologies gave differing views of the amount of variation present but all showed a high level of genetic variation in E. caninus. The following points may be drawn from this study whether based on RAPD, microsatellite, or isozyme data: (i) The Icelandic populations are consistently revealed by the three dendrograms. The congruence of the discrimination of this accession group by RAPD, microsatellite, and isozyme markers suggests that geographic isolation strongly influenced the evolution of the populations; (ii) The degree of genetic variation within accessions was notably great; and (iii) The DNA-based markers will be the more useful ones in detecting genetic diversity in closely related accessions. In addition, a dendrogram, which took into account all fragments produced by isozymes, RAPDs, and microsatellites, reflected better the relationships than did dendrograms based on only one type of marker.Key words: Elymus caninus, genetic diversity, isozymes, RAPDs, microsatellites.

Genetic variation within and among populations of Camelliajaponica (Theaceae) in Korea

1996 ◽  
Vol 26 (4) ◽  
pp. 537-542 ◽  
Author(s):  
Myong Gi Chung ◽  
Soon Suk Kang
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Pollen Dispersal ◽  
Island Populations ◽  
Generation Times ◽  
Genetic Diversity And Structure ◽  
Stump Sprouting ◽  
Ability To Regenerate ◽  
The Mean ◽  
High Level

The genetic diversity and structure of 17 Korean populations of Camelliajaponica L., a broad-leaved evergreen tree, was examined. Although most populations are restricted to several islands near the southern and southwestern coast of the Korean Peninsula, they maintain higher levels of genetic variation within populations than do long-lived, woody angiosperms. For example, 13 of 16 loci examined were polymorphic in at least one population, the mean number of alleles per locus was 2.63, and mean expected heterozygosity was 0.265. These values were comparable with those for continuously distributed, mainland populations of C. japonica in Japan. However, a considerably high level of heterozygote deficiency was observed in Korean populations of C. japonica (mean FIS = 0.202). About 13% of the total genetic variation was found among populations (GST = 0.129). Indirect estimates of the number of migrants per generation (1.69, calculated from FST; 2.14, calculated from the mean frequency of eight private alleles) indicate that gene flow among island populations is moderate. Factors contributing to the high levels of genetic diversity found in the entire species of C. japonica include long generation times, ability to regenerate by stump sprouting, predominant outcrossing induced by animal vectors, and occasional pollen dispersal by birds.

scholarly journals Genetic variation among Iranian alfalfa (Medicago sativa L.) populations based on RAPD markers

2011 ◽  
Vol 18 (2) ◽  
pp. 93-104 ◽  
Author(s):  
Fatemeh Mohammadzadeh ◽  
Hassan Monirifar ◽  
Jalal Saba ◽  
Mostafa Valizadeh ◽  
Ahmad Razban Haghighi ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Cluster Analysis ◽  
Genetic Variation ◽  
Breeding Population ◽  
Genetic Distances ◽  
Analysis Of Molecular Variance ◽  
Molecular Variance ◽  
Geographical Patterns ◽  
Plant Taxon ◽  
High Level

Genetic diversity among and within 10 populations of Iranian alfalfa, from different areas of Azarbaijan, Iran was analyzed by screening DNA from seeds of individual plants and bulk samples. In individual study, 10 randomly amplified polymorphic DNA (RAPD) primers produced 156 polymorphic bands and a high level of genetic diversity was observed within populations. The averages of total and within population genetic diversity were 0.2349 and 0.1892, respectively. Results of analysis of molecular variance (AMOVA) showed the great genetic variation existed within populations (81.37%). These Results were in agreement with allogamous and polyploid nature of alfalfa. Cluster analysis was performed based on Nei’s genetic distances resulting in grouping into 3 clusters which could separate breeding population from other populations. Results of cluster analysis were in consistent with morphological and geographical patterns of populations. The results of bulk method were different from individual analysis. Our results showed that RAPD analysis is a suitable method to study genetic diversity and relationships among alfalfa populations.Keywords: Alfalfa; RAPD; Genetic diversity; Analysis of Molecular Variance; Cluster analysis.DOI: http://dx.doi.org/10.3329/bjpt.v18i2.9296Bangladesh J. Plant Taxon. 18: (2): 93-104, 2011 (December)

Genetic diversity of arctic bramble (Rubus arcticus L. subsp. arcticus) as measured by amplified fragment length polymorphism

2003 ◽  
Vol 81 (8) ◽  
pp. 805-813 ◽  
Author(s):  
Hannele Lindqvist-Kreuze ◽  
Hilkka Koponen ◽  
Jari P.T Valkonen
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Fragment Length ◽  
Natural Habitat ◽  
Genotypic Variation ◽  
Natural Populations ◽  
Shannon Index ◽  
Length Polymorphisms ◽  
Amplified Fragment Length Polymorphisms ◽  
High Level

The levels of genotypic and genetic variation were estimated in six natural populations of arctic bramble (Rubus arcticus L. subsp. arcticus) in Finland. Using three primer combinations, a total of 117 amplified fragment length polymorphisms (AFLP) were found. The results were highly reproducible and allowed identification of 78 genets among the 122 plants of arctic bramble studied. Genotypic variation measured as Simpson index (D) was high in all populations, ranging from 0.72 to 0.94. Also, the level of genetic variation measured as Shannon index was relatively high in all populations, ranging from 0.19 to 0.32 (average 0.26). The high levels of genetic diversity indicate that sexual reproduction has played a significant role in these populations. The hierarchical analysis of molecular variance (AMOVA) partitioned 48% of the genetic variation among populations, suggesting a high level of population differentiation and a low level of interpopulation gene flow. Genetic diversity among ten currently grown cultivars of arctic bramble and hybrid arctic bramble (R. arcticus subsp. arcticus × R. arcticus subsp. stellatus) was large, and the subspecies were clearly distinguished from each other based on the AFLP marker data.Key words: AFLP, AMOVA, population, natural habitat, Rubus arcticus subsp. arcticus, Rubus arcticus subsp. stellatus.

Analysis of genetic diversity and spatial structure in Tunisian populations of Hordeum marinum ssp. marinum based on molecular markers

2019 ◽  
Vol 157 (5) ◽  
pp. 399-412 ◽  
Author(s):  
W. Saoudi ◽  
M. Badri ◽  
M. Gandour ◽  
A. Smaoui ◽  
C. Abdelly ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Random Amplified Polymorphic Dna ◽  
Geographic Origin ◽  
Conservation Strategies ◽  
Entire Collection ◽  
High Discrimination ◽  
High Level ◽  
Dna Primers ◽  
Altitudinal Difference

AbstractHordeum marinum commonly known as sea barley is a salinity-tolerant species of grass. In the current study, 150 lines from ten populations of H. marinum ssp. marinum collected from five Tunisian bioclimatic sites were screened for polymorphism with 13 selected random amplified polymorphic DNA primers. Results exhibited a high level of polymorphism (160 polymorphic bands with an average of 12.46 per primer) and a high level of genetic diversity in all the studied populations (on average UHe = 0.247 and I = 0.358). High discrimination capacity was found for the 13 primers and a combination of three allowed assignation of a unique profile for each of the 150 lines. The partition of genetic diversity with Analysis of Molecular Variance suggested that the majority of genetic variation (67%) was within populations. The components between-populations within ecoregions and between-ecoregions explained 21 and 12%, respectively, of the total genetic variance. There was no significant association of population differentiation (ФPT) with geographical distance or altitudinal difference. Results also showed that the 150 lines grouped into three clusters with no respect to geographic origin. A sub-set of 13 lines was identified, which captured the maximum genetic diversity of the entire collection. The genetic variation found in this collection of H. marinum is deemed to be useful in formulating conservation strategies for this species.

scholarly journals Forest decline has not reduced genetic diversity of naturally regenerated Norway spruce from the Beskids, Poland

2015 ◽  
Vol 64 (1-6) ◽  
pp. 270-278 ◽  
Author(s):  
Elżbieta Chomicz-Zegar ◽  
J. A. Nowakowska ◽  
A. Tereba
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Norway Spruce ◽  
Forest Decline ◽  
Gene Diversity ◽  
Young Generation ◽  
Primeval Forest ◽  
Initial Stage ◽  
Spruce Stands ◽  
High Level

AbstractNorway spruce forests decline in the Beskids raises concerns about reduction of genetic variation in a next generation of forest. We aim to determine whether the genetic diversity in declining spruce stands was successfully transmitted to its self-seeded progeny. Using three nuclear microsatellite markers, we carried out the genetic assessment of naturally regenerated progeny and compered them with their maternal stands at an initial stage of decline. We investigated three spruce stands from the Śląski and Żywiecki Beskid and one primeval forest from the Tatras, as a reference. We noticed a high level of gene diversity, allelic richness and an effective number of alleles in progeny of all stands, without differences between declining stands from the Beskids and the primeval forest. The gene diversity was similar in maternal trees and their offspring. Higher gene diversity and generally higher number of alleles were noticed in young generation of stands. Genetic identity between generations was high in analyzed seed stands and the highest in the primeval forest. The results we presented indicate no significant effect of drastic reduction in the population size due to the forest decline on the level of genetic variation in self-seeded progeny of Norway spruce from the Beskids.

scholarly journals Genetic variation and population structure of clonal Zingiber zerumbet at a fine geographic scale: a comparison with two closely related selfing and outcrossing Zingiber species

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Rong Huang ◽  
Yu Wang ◽  
Kuan Li ◽  
Ying-Qiang Wang
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Genetic Variation ◽  
Plant Species ◽  
Population Genetic ◽  
Clonal Plants ◽  
Zingiber Zerumbet ◽  
Population Genetic Diversity ◽  
Local Populations ◽  
High Level

Abstract Background There has always been controversy over whether clonal plants have lower genetic diversity than plants that reproduce sexually. These conflicts could be attributed to the fact that few studies have taken into account the mating system of sexually reproducing plants and their phylogenetic distance. Moreover, most clonal plants in these previous studies regularly produce sexual progeny. Here, we describe a study examining the levels of genetic diversity and differentiation within and between local populations of fully clonal Zingiber zerumbet at a microgeographical scale and compare the results with data for the closely related selfing Z. corallinum and outcrossing Z. nudicarpum. Such studies could disentangle the phylogenetic and sexually reproducing effect on genetic variation of clonal plants, and thus contribute to an improved understanding in the clonally reproducing effects on genetic diversity and population structure. Results The results revealed that the level of local population genetic diversity of clonal Z. zerumbet was comparable to that of outcrossing Z. nudicarpum and significantly higher than that of selfing Z. corallinum. However, the level of microgeographic genetic diversity of clonal Z. zerumbet is comparable to that of selfing Z. corallinum and even slightly higher than that of outcrossing Z. nudicarpum. The genetic differentiation among local populations of clonal Z. zerumbet was significantly lower than that of selfing Z. corallinum, but higher than that of outcrossing Z. nudicarpum. A stronger spatial genetic structure appeared within local populations of Z. zerumbet compared with selfing Z. corallinum and outcrossing Z. nudicarpum. Conclusions Our study shows that fully clonal plants are able not only to maintain a high level of within-population genetic diversity like outcrossing plants, but can also maintain a high level of microgeographic genetic diversity like selfing plant species, probably due to the accumulation of somatic mutations and absence of a capacity for sexual reproduction. We suggest that conservation strategies for the genetic diversity of clonal and selfing plant species should be focused on the protection of all habitat types, especially fragments within ecosystems, while maintenance of large populations is a key to enhance the genetic diversity of outcrossing species.

scholarly journals HUMAN ADENOVIRUS TYPE 4 COMPRISES TWO MAJOR PHYLOGROUPS WITH DISTINCT REPLICATIVE FITNESS AND VIRULENCE PHENOTYPES

2020 ◽  
Author(s):  
Camden R Bair ◽  
Wei Zhang ◽  
Gabriel Gonzalez ◽  
Arash Kamali ◽  
Daniel Stylos ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Variability ◽  
Rat Model ◽  
Phenotypic Diversity ◽  
Human Adenovirus ◽  
Adenovirus Type ◽  
Polymorphism Analysis ◽  
Cotton Rat ◽  
Replicative Fitness

Human adenovirus type 4 (HAdV-E4) is the only type (and serotype) classified within species Human mastadenovirus E that has been isolated from a human host to the present. Recent phylogenetic analysis of whole genome sequences of strains representing the spectrum of intratypic genetic diversity described to date identified two major evolutionary lineages designated phylogroups (PG) I, and II, and validated the early clustering of HAdV-E4 genomic variants into two major groups by low resolution restriction fragment length polymorphism analysis. In this study we expanded our original analysis of intra- and inter-PG genetic variability, and used a panel of viruses representative of the spectrum of genetic diversity described for HAdV-E4 to examine the magnitude of inter- and intra-PG phenotypic diversity using an array of cell-based assays and a cotton rat model of HAdV respiratory infection. Our proteotyping of HAdV-E strains using concatenated protein sequences in selected coding regions including E1A, E1B-19K and -55K, DNA polymerase, L4-100K, various E3 proteins, and E4-34K confirmed that the two clades encode distinct variants/proteotypes at most of these loci. Our in vitro and in vivo studies demonstrated that PG I and PG II differ in their growth, spread, and cell killing phenotypes in cell culture and in their pulmonary pathogenic phenotypes. Surprisingly, the differences in replicative fitness documented in vitro between PGs did not correlate with the differences in virulence observed in the cotton rat model. This body of work is the first reporting phenotypic correlates of naturally occurring intratypic genetic variability for HAdV-E4.

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