High genetic diversity in Chilean populations of wheat yellow rust (Puccinia striiformis f. sp. tritici West.) assessed by RAPD and AFLP

2007 ◽  
Vol 58 (6) ◽  
pp. 525 ◽  
Author(s):  
V. Becerra ◽  
M. Paredes ◽  
R. Madariaga ◽  
H. S. Bariana ◽  
M. Mellado ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Puccinia Striiformis ◽  
Yellow Rust ◽  
Geographic Origin ◽  
Adult Plant ◽  
Frequent Change ◽  
High Genetic Diversity ◽  
Production Area ◽  
Plant Resistance Gene ◽  
High Level

Wheat yellow rust (Puccinia striiformis f. sp. tritici West. PST) is one of the main fungal diseases that causes major yield losses in the central and southern wheat production area of Chile. Chilean plant breeding programs have been using specific resistance genes to control this disease and resistance was frequently lost due to the appearance of new pathotypes of this pathogen. This resulted in a frequent change of wheat cultivars in the country. The objective of this work was to determine the genetic polymorphism among PST samples collected in wheat fields throughout the country, using randomly amplified polymorphic DNA (RAPD), and amplified fragment length polymorphism (AFLP). Twenty-nine PST populations from 5 locations were analysed with 64 RAPD primers and 6 combinations of AFLP primers. The coefficients of similarity (53% for RAPD and 14% for AFLP) indicated that the populations of yellow rust in Chile are highly diverse, in contrast with similar studies performed in other countries. This observation is supported by the virulence spectrum of PST population. This stressed the need to pyramid 2 or more major genes in commercial cultivars. Alternatively, the deployment of adult plant resistance gene combinations should be conducted. AFLP technique was more robust for analysis of the genetic diversity of PST compared with RAPD, because of its reproducibility and high level of polymorphism. The analysis of genetic similarity data among yellow rust populations grouped most of the PST population according to their geographic origin.

Genetic diversity of mocó cotton (Gossypium hirsutum race marie-galante) from the northeast of Brazil: implications for conservation

Botany ◽  
2010 ◽  
Vol 88 (8) ◽  
pp. 765-773 ◽  
Author(s):  
Ivandilson Pessoa Pinto de Menezes ◽  
Paulo Augusto Vianna Barroso ◽  
Lúcia Vieira Hoffmann ◽  
Valeska Silva Lucena ◽  
Marc Giband
Keyword(s):  
Genetic Diversity ◽  
Gossypium Hirsutum ◽  
Geographic Origin ◽  
Rio Grande ◽  
Ex Situ ◽  
High Genetic Diversity ◽  
Breeding Programs ◽  
Extinction Process ◽  
Total Genetic Diversity ◽  
High Level

Mocó cotton ( Gossypium hirsutum  L. race marie-galante (Watt) Hutch.) is a potential source of valuable alleles for breeding programs, mainly because of its great adaptability to semi-arid conditions. With the aim of quantifying mocó cotton genetic variability, 187 plants collected in the northeast of Brazil were evaluated using 12 microsatellite markers. A total of 62 alleles were amplified, ranging from three to eight polymorphic alleles per locus. Total genetic diversity was high (0.52), and when measured on a per state basis, was of 0.37 on average. The population showed a low level of heterozygozity (HO = 0.16), reflecting a high level of endogamy (FIS = 0.67). Phylogenetic analysis using the neighbor-joining method revealed that plants sampled in different states tended to cluster according to their geographic origin, except for those collected in the states of Paraíba and Rio Grande do Norte, which grouped together. Plants from the state of Piauí formed two groups, one with an apparent allelic contribution from G. barbadense, while the second group of plants was closer to those from the states of Paraíba and Rio Grande do Norte. Despite the high genetic diversity that was observed in the remaining populations, urgent conservation efforts should be undertaken, owing to the high level of endogamy and accelerated extinction process that characterizes these populations. Such efforts should focus on the collection and ex situ maintenance of representative genetic diversity.

scholarly journals Microsatellite genotyping from faeces of Lontra longicaudis from southern Brazil

2009 ◽  
Vol 99 (1) ◽  
pp. 5-11 ◽  
Author(s):  
Laura I. Weber ◽  
Cintia G. Hildebrand ◽  
Anderson Ferreira ◽  
Gustavo Pedarassi ◽  
José A. Levy ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Conservation Status ◽  
Significant Degree ◽  
Southern Brazil ◽  
High Genetic Diversity ◽  
Low Degree ◽  
Faecal Samples ◽  
High Level ◽  
Degree Of Differentiation ◽  
Lontra Longicaudis

A genetic study of the neotropical river otter Lontra longicaudis (Olfers, 1818), which has an unknown conservation status, was carried out at the Taim Ecological Station and the margins of the Vargas stream, Rio Grande do Sul, southern Brazil. Faecal samples were collected, and DNA was extracted using a silica-guanidine method. Five microsatellite loci were amplified using PCR with heterologous primers previously described for Lutra lutra (Linnaeus, 1758). Sixteen faecal samples out of 29 from Taim and 11 out of 14 from Vargas stream margins contained enough DNA for genetic analysis. A total of 49 different alleles were found at both localities, from which 18 were exclusively found in individuals from Taim and 17 were exclusives from Vargas individuals. The most common allele was the same at both locations for three loci (Lut715, Lut733, and Lut818). A high level of genetic diversity was found at both sites (NeTaim=4.1, HoTaim=0.299, HeTaim=0.681; NeVargas=4.9, HoVargas=0.355, HeVargas=0.724), being higher at the Vargas stream site. A high and significant level of heterozygote deficiency was observed at most loci according to the χ2 test. The homogeneity χ2 test (P<0.001) showed that there were significant differences in the allele frequencies between the two locations. Genotyping for more than one locus was possible in 81.5% of samples, from which only 37% were possible to genotype for more than three loci. A low degree of relatedness was found among individuals from Taim (R=0.055±0.310), but an even lower value of relatedness was found at the Vargas site (R= -0.285±0.440). The significant degree of differentiation (I=0.890; F ST=0.059) found between Taim and Vargas individuals suggests that there is more than one population of otters in the southern extreme of Brazil, which probably are associated with the water body systems found in this region, the Mirim and the Caiuvá/Flores/Mangueira Lagoons. The high genetic diversity and low relatedness found at the Vargas stream, lead us to believe that the Vargas stream may be acting as a corridor between these water bodies for otter dispersion.

High-temperature adult-plant resistance to stripe rust in facultative winter wheat

2016 ◽  
Vol 67 (10) ◽  
pp. 1064 ◽  
Author(s):  
Beyhan Akin ◽  
Xian Ming Chen ◽  
Alex Morgunov ◽  
Nusret Zencirci ◽  
Anmin Wan ◽  
...  
Keyword(s):  
Molecular Markers ◽  
High Temperature ◽  
Winter Wheat ◽  
Stripe Rust ◽  
Field Experiments ◽  
Puccinia Striiformis ◽  
Yellow Rust ◽  
Stripe Rust Resistance ◽  
Adult Plant ◽  
Improvement Program

Stripe (yellow) rust, caused by Puccinia striiformis Westend. f. sp. tritici Erikss., is one of the most damaging diseases in wheat and is especially damaging for winter and facultative wheat. The objective of this study was to understand stripe rust resistance in 100 wheat and facultative wheat entries from the International Winter Wheat Improvement Program by conducting experiments in a greenhouse and in four field environments in Washington State, USA, and by genotyping molecular markers linked to Yr genes. Percentages of entries resistant to the rust races at the seedling stage were: PST-17, 44%; PST-37, 32%; PST-43, 45%; PST-45, 49%; PST-116, 18%; PST-100, 17%; and PST-127, 8%. Molecular markers were positive for genes Yr9, Yr17, and Yr18 and negative for Yr5, Yr10, and Yr15. Yr18 was present in 44 entries (44%). By using the highly virulent races PST-127 and PST-100 under controlled conditions, 16 entries were shown to have high-temperature adult-plant (HTAP) resistance and resistant–moderately resistant field reactions at all four field sites. Resistant entries, especially those with HTAP resistance, were also identified in the field experiments.

scholarly journals Assessment of Genetic Diversity and Marker-Trait Associations Using Selected Early Maize Inbreds Derived From Local Landraces of Eastern Himalayan Regions

2021 ◽  
Author(s):  
E. Lamalakshmi Devi ◽  
Umakanta Ngangkham ◽  
Akoijam Ratankumar Singh ◽  
Bhuvaneswari S ◽  
Konsam Sarika ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Agronomic Traits ◽  
Crop Improvement ◽  
Mean Value ◽  
Cross Combination ◽  
High Genetic Diversity ◽  
Average Value ◽  
Maize Inbreds ◽  
High Level ◽  
Trait Associations

Abstract North- Eastern parts of India fall under Eastern Himalayan region and it is a diversity hotspot of many crops including maize. Evaluation of genetic diversity is required to tape the potentiality of genetic resources in any crop improvement programmes. In the present study, genetic diversity at fifty two microsatellite markers were conducted in 30 early maize inbreds developed from local landraces of NE India. Genetic diversity analysis revealed a total of 189 alleles with a mean of 3.63 alleles/ locus. The allele size ranged from 50 bp (phi 036) to 295 bp (p 101049) which revealed a high level of genetic diversity among the loci. The PIC among the 30 genotypes ranged from 0.17 (umc 1622) to 0.76 (umc 1153) with an average value of 0.49. The value of Expected Heterozygosity (HExp) ranged from 0.19 to 0.80 with an average of 0.57, whereas the Observed Heterozygosity (HObs) ranged from 0 to 0.89 with a mean of 0.14.The genetic dissimilarity between the genotype pairs ranged from 0.40 to 0.64 with a mean value of 0.57. Cluster analysis grouped the 30 inbreds into distinct three sub-clusters. Similarly, population structure and principal coordinate analysis) analysis also classified the 30 inbred lines into three-subpopulations. AMOVA revealed that 6% of total variance is due to differences among populations, while 94% of total molecular variance is accounted by within populations. Marker-trait associations showed a total of twelve SSR markers significantly associated with seven agronomic traits. From the present finding, these results show that the thirty maize inbreds have high genetic diversity which would be useful for choosing promising parents and for making cross combination based on genetic distance and clustering for genetic improvement programmes of maize.

scholarly journals Wheat Genetic Loci Conferring Resistance to Yellow Rust in the Face of Recent Epidemics of Genetically Diverse Races of the Fungus Puccinia Striiformis F. Sp. Tritici

2021 ◽  
Author(s):  
Laura Bouvet ◽  
Lawrence Percival-Alwyn ◽  
Simon Berry ◽  
Paul Fenwick ◽  
Camila Campos Mantello ◽  
...  
Keyword(s):  
Phenotypic Variation ◽  
Puccinia Striiformis ◽  
Single Nucleotide Polymorphism Array ◽  
Yellow Rust ◽  
Durable Resistance ◽  
Genetic Resistance ◽  
Genomic Analysis ◽  
Major Effect ◽  
Wheat Breeding ◽  
Adult Plant

Abstract Yellow rust (YR), or stripe rust, is a major fungal disease of wheat (Triticum aestivum) caused by Puccinia striiformis f. sp. tritici (Pst). Since 2011, the historically clonal European Pst races have been superseded by the rapid incursion of genetically diverse lineages, reducing the resistance of varieties that previously showed durable resistance. Identification of sources of genetic resistance to such races is a high priority for wheat breeding. Here we use a wheat eight-founder multi-parent population genotyped with a 90,000 feature single nucleotide polymorphism array to genetically map adult plant YR resistance to such new Pst races. Analysis of five trials, at three sites in the UK, consistently identified four highly significant quantitative trait loci (QTL) across all test environments, located on chromosomes 1A (QYr.niab-1A.1), 2A (QYr.niab-2A.1), 2B (QYr.niab-2B.1) and 2D (QYr.niab-2D.1). Together these explained ~ 50% of the phenotypic variation, and genetic markers were developed that distinguished resistant and susceptible alleles. Analysis of these QTL in two-way and three-way combinations showed combinations conferred greater resistance than single QTL. Four additional major-effect QTL were detected in two or more trials, together explaining 15–20% of the phenotypic variation, as well as six minor QTL. Genomic analysis found the median physical interval size of these eight QTL to be 19.8 Mbp, and QYr.niab-2A.1 and QYr.niab-2D.1 to be at homoeologous locations on the group-2 chromosomes. Notably, the QYr.niab-2B.1 physical interval contained five nucleotide-binding leucine-rich repeat (NLR) candidate genes with integrated BED domains, of which two corresponded to the cloned resistance genes Yr7 and Yr5/YrSp.

scholarly journals Using Random Amplified Polymorphic DNA (RAPD) analysis to investigation of genetic diversity, and relationships among a set of clinical Aspergillus fumigatus isolates

2014 ◽  
Vol 8 (1) ◽  
pp. 46-54
Author(s):  
Batool Omran Theeb ◽  
Abdulkareem Jasim Hashim ◽  
Akeel Hussain Ali Al-Assi
Keyword(s):  
Genetic Diversity ◽  
Aspergillus Fumigatus ◽  
Genetic Relatedness ◽  
Random Amplified Polymorphic Dna ◽  
Geographic Origin ◽  
Close Relation ◽  
Genetic Distances ◽  
Universal Primers ◽  
Characteristic Banding ◽  
High Level

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.

scholarly journals Molecular Characterization of International Collections of the Wheat Stripe Rust Pathogen Puccinia striiformis f. sp. tritici Reveals High Diversity and Intercontinental Migration

2020 ◽  
Vol 110 (4) ◽  
pp. 933-942 ◽  
Author(s):  
Dipak Sharma-Poudyal ◽  
Qing Bai ◽  
Anmin Wan ◽  
Meinan Wang ◽  
Deven See ◽  
...  
Keyword(s):  
Stripe Rust ◽  
Puccinia Striiformis ◽  
Yellow Rust ◽  
Management Strategies ◽  
Global Scale ◽  
Asian Populations ◽  
Wheat Diseases ◽  
Geographic Regions ◽  
High Level

Puccinia striiformis f. sp. tritici causes stripe rust (yellow rust), one of the most important wheat diseases worldwide. To understand the genetic variation of the pathogen in a global scale, 283 P. striiformis f. sp. tritici isolates collected from 16 countries in eight geographic regions were genotyped using 24 codominant simple sequence repeat markers. The overall collection had a high level of genetic diversity, and the diversity levels in the Asian populations were generally higher than those of the other regions. Heterozygosity of isolates ranged from 0 to 75%, with an average of 46%. Mean heterozygosity in individual countries ranged from 34 to 59%. A total of 265 multilocus genotypes (MLGs) were detected, which were classified into eight molecular groups. Some of the molecular groups were present in all geographic regions. Moreover, many isolates from different regions were found to be identical or very closely related MLGs. Analysis of molecular variance revealed high variation within countries and intermediate variation between countries, but it revealed low and insignificant variation among geographic regions. Pairwise comparisons of regional populations detected considerable effective migrants and only low to moderate levels of differentiation. The molecular genotypes had a moderate level of correlation with the virulence phenotypes, and some of the molecular/virulence groups contained isolates from different continents. The results indicate tremendous migrations of P. striiformis f. sp. tritici and warrant the development of management strategies considering the global pathogen population.

scholarly journals Yr36 Confers Partial Resistance at Temperatures Below 18°C to U.K. Isolates of Puccinia striiformis

2014 ◽  
Vol 104 (8) ◽  
pp. 871-878 ◽  
Author(s):  
Vanesa Segovia ◽  
Amelia Hubbard ◽  
Melanie Craze ◽  
Sarah Bowden ◽  
Emma Wallington ◽  
...  
Keyword(s):  
Partial Resistance ◽  
Field Experiments ◽  
Puccinia Striiformis ◽  
Yellow Rust ◽  
Adult Plant ◽  
Slow Rusting ◽  
The United Kingdom ◽  
Yellow Stripe ◽  
Potential Use ◽  
Effective Source

Wheat yellow (stripe) rust, caused by the obligate biotrophic fungus Puccinia striiformis f. sp. tritici, is a continual threat to wheat fields worldwide. New isolates with increased virulence have recently emerged driving breeding efforts to incorporate disease resistance genes which confer potentially more durable, albeit partial, resistance. Yr36 is one such locus which was recently cloned (WKS1) and described as a high-temperature adult-plant gene being effective only at temperatures above 25°C. We examined the potential use of Yr36 at temperatures below 25°C. Field experiments in the United Kingdom across 2 years show that lines carrying Yr36 provide slow rusting resistance to the yellow rust pathogen. Juvenile and adult Yr36 isogenic lines showed partial resistance at temperatures below 18°C under control environment conditions in tetraploid and hexaploid genetic backgrounds, but not at seedling stage, when inoculated with U.K. P. striiformis isolates. This partial resistance phenotype was similar to that observed previously at temperatures ≥25°C. Transgenic complementation tests and ethyl methanesulfonate mutants showed that the low-temperature partial resistance was due to the WKS1 gene. This study indicates that Yr36 has the potential to be an effective source of partial resistance in temperate wheat growing regions.

scholarly journals Morphological and Isozyme Variation in Natural Populations of the Genus Medicago L. Prospected in Northern Algeria

2015 ◽  
Vol 43 (1) ◽  
pp. 86-95 ◽  
Author(s):  
Imane MEDOUKALI ◽  
Ines BELLIL ◽  
Douadi KHELIFI
Keyword(s):  
Genetic Diversity ◽  
Natural Populations ◽  
Morphological Characteristics ◽  
Genetic Distances ◽  
Glutamate Oxaloacetate Transaminase ◽  
High Genetic Diversity ◽  
Isozyme Markers ◽  
Northern Algeria ◽  
Isozyme Variability ◽  
High Level

As part of the evaluation and enhancement of genetic resources, morphological and isozyme variability within and among 169 accessions, representing 14 species of the genus Medicago L. collected in northern Algeria, was assessed using twelve quantitative traits and two enzymatic systems. Phenotype frequencies were scored in six enzyme zones to determine isozyme variability within and among populations. The data analysis resolved a high level of genetic diversity. Ten morphometric characteristics contributed to the discrimination of the species. The relationship between the collection site environment and phenotypic characteristics was also studied. Esterase (EST) enzyme system was more polymorphic than glutamate oxaloacetate transaminase (GOT) system. Were scored 2 zones with 10 bands and 21 phenotypes for GOT (glutamate oxaloacetate transaminase) and 4 zones with 22 bands and 71 phenotypes for EST (esterase) Polymorphism index and Jaccard’s genetic distances revealed the existence of a high genetic diversity within and among the studied populations. The annual species M. polymorpha presented an intraspecific polymorphism index of 0.57, which was higher than all other species indices. Clustering of the species based on isozyme markers was in agreement with taxonomic criteria and showed no significant correlation with morphological characteristics. Conservation programs should take into account the level of genetic diversity within and between populations revealed by isozyme markers.

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