scholarly journals Genetic Diversity and Dynamics of Sinorhizobium meliloti Populations Nodulating Different Alfalfa Cultivars in Italian Soils

2000 ◽  
Vol 66 (11) ◽  
pp. 4785-4789 ◽  
Author(s):  
Maria Carelli ◽  
Stefano Gnocchi ◽  
Silvia Fancelli ◽  
Alessio Mengoni ◽  
Donatella Paffetti ◽  
...  

ABSTRACT We analyzed the genetic diversity of 531 Sinorhizobium meliloti strains isolated from nodules of Medicago sativa cultivars in two different Italian soils during 4 years of plant growth. The isolates were analyzed for DNA polymorphism with the random amplified polymorphic DNA method. The populations showed a high level of genetic polymorphism distributed throughout all the isolates, with 440 different haplotypes. Analysis of molecular variance allowed us to relate the genetic structure of the symbiotic population to various factors, including soil type, alfalfa cultivar, individual plants within a cultivar, and time. Some of these factors significantly affected the genetic structure of the population, and their relative influence changed with time. At the beginning of the experiment, the soil of origin and, even more, the cultivar significantly influenced the distribution of genetic variability of S. meliloti. After 3 years, the rhizobium population was altered; it showed a genetic structure based mainly on differences among plants, while the effects of soil and cultivar were not significant.

2011 ◽  
Vol 18 (2) ◽  
pp. 93-104 ◽  
Author(s):  
Fatemeh Mohammadzadeh ◽  
Hassan Monirifar ◽  
Jalal Saba ◽  
Mostafa Valizadeh ◽  
Ahmad Razban Haghighi ◽  
...  

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)


Plant Disease ◽  
2007 ◽  
Vol 91 (12) ◽  
pp. 1556-1563 ◽  
Author(s):  
R. G. Bhat ◽  
G. T. Browne

California populations of the plant pathogen Phytophthora citricola were examined for amplified fragment length polymorphism (AFLP), pathogenicity on almond, and sensitivity to mefenoxam. The characterizations of AFLP variation and mefenoxam sensitivity were based on 86 isolates (44 from almond, 11 from avocado, 3 from strawberry, 18 from walnut, and 10 from six other hosts). Cluster analysis of the AFLP data using the unweighted pair group method indicated a high level of genetic diversity among the isolates, and four main clusters were identified—one dominated by isolates from almond, another including all isolates from avocado, and two including isolates from several hosts other than avocado. Analysis of molecular variance revealed that 38.4 and 24.9% of the AFLP variation were associated with host and geographical factors, respectively. Of 24 isolates, including those from almond, avocado, strawberry, and walnut, 22 were aggressive on almond shoots; there was no evidence of host specificity. All but 1 of the 86 isolates grew at different rates on V8 juice medium amended with mefenoxam at 1 ppm, indicating partial tolerance to the fungicide. Isolates of P. citricola from California populations are genetically diverse, and much of the variation is associated with host and geography. These populations are all potentially pathogenic on almond and tolerant to mefenoxam.


1998 ◽  
Vol 88 (11) ◽  
pp. 1187-1191 ◽  
Author(s):  
Richard C. Hamelin ◽  
Mathieu Dusabenyagasani ◽  
Khalid Et-touil

The fine-level genetic structure of the white pine blister rust agent, Cronartium ribicola, was investigated by sampling multiple monokaryotic spermogonia directly on cankers in four eastern Canadian white pine (Pinus strobus) plantations and assessing genetic variability, using random amplified polymorphic DNA (RAPD) markers. Ninety-eight percent of the cankers surveyed contained a single DNA haplotype, suggesting spermogonia within cankers are the result of clonal reproduction. A single canker contained two haplotypes that were divided between the upper and lower parts of the canker, suggesting it represented two confluent cankers. In contrast, genotypic diversity was high among cankers. Thirty-seven haplotypes were found among forty-three cankers sampled, and an analysis of molecular variance indicated that 93% (P < 0.001) of the total genetic diversity was attributable to sampling of different cankers, strongly suggesting that multiple infections do not take place in the white pine blister rust pathosystem, i.e., a canker is the result of infection by a single genotype. This result is in contrast with the high level of genetic diversity previously reported among dikaryotic aecidia within cankers and is consistent with the hypothesis that variability in the aecidial stage is the result of outcrossing between resident spermogonia and alien spermatia. The genetic structure of the spermogonial stage, which is the vegetative extension of infection by basidiospores and, therefore, the indirect result of meiosis, was consistent with random mating; the observed genotypic diversity was not significantly different (P > 0.05) from the genotypic diversity expected under the assumption of panmixis. The results indicate that monokaryotic cankers can be genotyped by sampling a single unopened spermogonia per canker.


AGROFOR ◽  
2016 ◽  
Vol 1 (3) ◽  
Author(s):  
Veronika KUKUČKOVÁ ◽  
Nina MORAVČÍKOVÁ ◽  
Radovan KASARDA

The aim of this study was to assess genetic structure of Slovak Pinzgau populationbased on polymorphism at molecular markers using statistical methods. Femaleoffspring of 12 most frequently used bulls in Slovak Pinzgau breeding programmewere investigated. Pinzgau cattle were found to have a high level of diversity,supported by the number of alleles observed across loci (average 5.31, range 2-11)and by the high within-breed expected heterozygosity (average 0.66, range 0.64-0.73). The state of genetic diversity is satisfying and standard for local populations.Detection of 12 possible subpopulation structures provided us with detailedinformation of the genetic structure. The Bayesian approach was applied, detectingthree, as the most probable number of clusters. The similarity of eachsubpopulation using microsatellites was confirmed also by high-throughputmolecular data. The observed inbreeding (FROH=2.3%) was higher than thatexpected based on pedigree data (FPED=0.4%) due to the limited number ofavailable generations in pedigree data. One of the most important steps indevelopment of efficient autochthonous breed protection programs ischaracterization of genetic variability and assessment of the population structure.The chosen set of microsatellites confirmed the suitability in determination of thesubpopulations of Pinzgau cattle in Slovakia. The state of genetic diversity at moredetailed level was successfully performed using bovineSNP50 BeadChip.


2011 ◽  
Vol 11 (3) ◽  
pp. 216-223 ◽  
Author(s):  
Liene Rocha Picanço Gomes ◽  
Maria Teresa Gomes Lopes ◽  
Jania Lilia da Silva Bentes ◽  
Willian Silva Barros ◽  
Pedro de Queiroz Costa Neto ◽  
...  

This study aimed to characterize the genetic diversity of buriti populations by AFLP (Amplified Fragment Length Polymorphism) markers. The analysis was performed in four populations used by traditional communities in the state of Amazonia (Bom Jesus do Anamã, Lauro Sodré, Santa Luzia do Buiçuzinho, and Esperança II). From each population 30 plants were randomly selected. To obtain the markers four primer combinations were used. The percentage of polymorphic loci was estimated, the molecular variance among and within populations analyzed and a dendrogram constructed. The primers detected 339 polymorphic loci ranging from 81.1 % to 91.1 % among populations. Analysis of molecular variance attributed 77.18 % to variation within and 22.8 % to variation between populations. The dendrogram indicated the formation of two groups, showing that the populations of Bom Jesus do Anamã and Lauro Sodré are genetically most similar and thet the genetic and geographical distances are not correlated.


2002 ◽  
Vol 53 (6) ◽  
pp. 629 ◽  
Author(s):  
J. M. Musial ◽  
K. E. Basford ◽  
J. A. G. Irwin

Lucerne (Medicago sativa L.) is autotetraploid, and predominantly allogamous. This complex breeding structure maximises the genetic diversity within lucerne populations making it difficult to genetically discriminate between populations. The objective of this study was to evaluate the level of random genetic diversity within and between a selection of Australian-grown lucerne cultivars, with tetraploid M. falcata included as a possible divergent control source. This diversity was evaluated using random amplified polymorphic DNA (RAPDs). Nineteen plants from each of 10 cultivars were analysed. Using 11 RAPD primers, 96 polymorphic bands were scored as present or absent across the 190 individuals. Genetic similarity estimates (GSEs) of all pair-wise comparisons were calculated from these data. Mean GSEs within cultivars ranged from 0.43 to 0.51. Cultivar Venus (0.43) had the highest level of intra-population genetic diversity and cultivar Sequel HR (0.51) had the lowest level of intra-population genetic diversity. Mean GSEs between cultivars ranged from 0.31 to 0.49, which overlapped with values obtained for within-cultivar GSE, thus not allowing separation of the cultivars. The high level of intra- and inter-population diversity that was detected is most likely due to the breeding of synthetic cultivars using parents derived from a number of diverse sources. Cultivar-specific polymorphisms were only identified in the M. falcata source, which like M. sativa, is outcrossing and autotetraploid. From a cluster analysis and a principal components analysis, it was clear that M. falcata was distinct from the other cultivars. The results indicate that the M. falcata accession tested has not been widely used in Australian lucerne breeding programs, and offers a means of introducing new genetic diversity into the lucerne gene pool. This provides a means of maximising heterozygosity, which is essential to maximising productivity in lucerne.


2018 ◽  
Vol 56 (3) ◽  
pp. 275
Author(s):  
Tran Thi Lieu ◽  
Dinh Thi Phong ◽  
Vu Thi Thu Hien

Keteleeria evelyniana Mast. is a big softwood species with high economic values. Therefore, the number of these trees are rapidly decreasing due to rampant exploitation as well as its habitat loss and recently, the species is considered vulnerablein Vietnam. In this study, we assessed the genetic variation among seventy K. evelyniana samples of three natural populations in Lam Dong, Dak Lak and Kon Tum using 16 microsatellite markers. The results showed that thirteen markers were polymorphic. A total 39 DNA fragments were amplified, among them, thirty – five were polymorphic (accounting for 89.74%). Among studied populations, the level of genetic diversity at Lam Dong (Na = 2.063; Ne = 1.730; Ap = 0.375; I = 0.558; Ho = 0.459 and He = 0.367) was the highest. Analysis of molecular variance (AMOVA) showed that the total level of molecular changes between populations was 34.65% and between individuals in the same population was 65.35%. Private alleles (Ap) and inbreeding values (Fis) of K. evelyniana species were founded of all three populations in Lam Dong, Dak Lak and Kon Tum (0.375 and -0.234; 0.188 and -0.065; 0.063 and -0.047, respectively). The gene flow (Nm) also occurred among the K. evelyniana populations with the average of Nm = 5.423. A dendrogram (UPGMA) constructed based on the similarity matrix of 70 K. evelyniana samples divided into two main groups with their genetic similarity coefficient ranged from 76.5% (Ke26 and Ke44) to 99% (Ke23 and Ke25). The obtained results indicated the importance of conserving the genetic resources of K. evelyniana species in Tay Nguyen.


2014 ◽  
Vol 8 (1) ◽  
pp. 46-54
Author(s):  
Batool Omran Theeb ◽  
Abdulkareem Jasim Hashim ◽  
Akeel Hussain Ali Al-Assi

This study is an attempt to determine the genetic diversity and relationships among fourteen local isolate isolated from patients with Aspergillosis (Aspergillus fumigatus) by using the Random Amplified Polymorphic DNA (RAPD) technique. Twelve universal primers used in this study produced 94 bands across fourteen isolates. Of these bands, 67 bands or 71.2% were polymorphic. The size of the amplified bands ranged between 100-2000 bp. The genetic polymorphism value of each primer was determined and ranged between 33-100%. In terms of unique banding patterns, determine the finger print for six isolates the most characteristic banding pattern was for the (AFU1, AFU2, AFU3, AFU4, AFU8 and AFU14) with primer (OP F-16 , OP I-06, OP F-16, OP X-01, OP X-01and OP A-06). Genetic distances ranged from 0.12419 to 0.64404 among A. fumigatus isolates. Cluster analyses were performed to construct a dendrogram among studied A. fumigatus isolates. The cluster analysis places most of the A.fumigatus isolates isolated from patient come from yhe same area into a close relation (subcluster) showing a high level of genetic relatedness and were distinct from isolates from another area (the other subcluster). Interestingly, a number of isolates originating from the same sources did form well defined groups, indicating association between the RAPD patterns and the geographic origin of the isolates. The information generated from this study can be used in the future for controlling of Aspergillosis programs.


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