scholarly journals Genetic Diversity of Plum Curculio (Coleoptera: Curculionidae) among Geographical Populations in the Eastern United States

2008 ◽  
Vol 101 (5) ◽  
pp. 824-832 ◽  
Author(s):  
Xing Zhang ◽  
Zhijian Tu ◽  
Shirley Luckhart ◽  
Douglas G. Pfeiffer
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Eastern United States ◽  
Plum Curculio ◽  
Geographical Populations

scholarly journals Contrasting Patterns of Genetic Diversity and Population Structure of Armillaria mellea sensu stricto in the Eastern and Western United States

2010 ◽  
Vol 100 (7) ◽  
pp. 708-718 ◽  
Author(s):  
Kendra Baumgartner ◽  
Renaud Travadon ◽  
Johann Bruhn ◽  
Sarah E. Bergemann
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Population Structure ◽  
Los Angeles ◽  
The United States ◽  
Sensu Stricto ◽  
Western United States ◽  
Eastern United States ◽  
Armillaria Mellea ◽  
Genetic Pools

Armillaria mellea infects hundreds of plant species in natural and managed ecosystems throughout the Northern hemisphere. Previously reported nuclear genetic divergence between eastern and western U.S. isolates is consistent with the disjunct range of A. mellea in North America, which is restricted mainly to both coasts of the United States. We investigated patterns of population structure and genetic diversity of the eastern (northern and southern Appalachians, Ozarks, and western Great Lakes) and western (Berkeley, Los Angeles, St. Helena, and San Jose, CA) regions of the United States. In total, 156 diploid isolates were genotyped using 12 microsatellite loci. Absence of genetic differentiation within either eastern subpopulations (θST = –0.002, P = 0.5 ) or western subpopulations (θST = 0.004, P = 0.3 ) suggests that spore dispersal within each region is sufficient to prevent geographic differentiation. In contrast to the western United States, our finding of more than one genetic cluster of isolates within the eastern United States (K = 3), revealed by Bayesian assignment of multilocus genotypes in STRUCTURE and confirmed by genetic multivariate analyses, suggests that eastern subpopulations are derived from multiple founder sources. The existence of amplifiable and nonamplifiable loci and contrasting patterns of genetic diversity between the two regions demonstrate that there are two geographically isolated, divergent genetic pools of A. mellea in the United States.

Sequence typing reveals extensive strain diversity of the Lyme borreliosis agents Borrelia burgdorferi in North America and Borrelia afzelii in Europe

Microbiology ◽  
2004 ◽  
Vol 150 (6) ◽  
pp. 1741-1755 ◽  
Author(s):  
Jonas Bunikis ◽  
Ulf Garpmo ◽  
Jean Tsao ◽  
Johan Berglund ◽  
Durland Fish ◽  
...  
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Membrane Protein ◽  
Borrelia Burgdorferi ◽  
Outer Membrane ◽  
Lyme Borreliosis ◽  
Outer Membrane Protein ◽  
Eastern United States ◽  
The North ◽  
North Eastern

The genetic polymorphism of Borrelia burgdorferi and Borrelia afzelii, two species that cause Lyme borreliosis, was estimated by sequence typing of four loci: the rrs–rrlA intergenic spacer (IGS) and the outer-membrane-protein gene p66 on the chromosome, and the outer-membrane-protein genes ospA and ospC on plasmids. The major sources of DNA for PCR amplification and sequencing were samples of the B. burgdorferi tick vector Ixodes scapularis, collected at a field site in an endemic region of the north-eastern United States, and the B. afzelii vector Ixodes ricinus, collected at a similar site in southern Sweden. The sequences were compared with those of reference strains and skin biopsy isolates, as well as database sequences. For B. burgdorferi, 10–13 alleles for each of the 4 loci, and a total of 9 distinct clonal lineages with linkage of all 4 loci, were found. For B. afzelii, 2 loci, ospC and IGS, were examined, and 11 IGS genotypes, 12 ospC alleles, and a total of 9 linkage groups were identified. The genetic variants of B. burgdorferi and B. afzelii among samples from the field sites accounted for the greater part of the genetic diversity previously reported from larger areas of the north-eastern United States and central and northern Europe. Although ospC alleles of both species had higher nucleotide diversity than other loci, the ospC locus showed evidence of intragenic recombination and was unsuitable for phylogenetic inference. In contrast, there was no detectable recombination at the IGS locus of B. burgdorferi. Moreover, beyond the signature nucleotides that specified 10 IGS genotypes, there were additional nucleotide polymorphisms that defined a total of 24 subtypes. Maximum-likelihood and parsimony cladograms of B. burgdorferi aligned IGS sequences revealed the subtype sequences to be terminal branches of clades, and the existence of at least three monophyletic lineages within B. burgdorferi. It is concluded that B. burgdorferi and B. afzelii have greater genetic diversity than had previously been estimated, and that the IGS locus alone is sufficient for strain typing and phylogenetic studies.

scholarly journals Identification and Mapping of Eastern Filbert Blight Resistance Quantitative Trait Loci in European Hazelnut Using Double Digestion Restriction Site Associated DNA Sequencing

2019 ◽  
Vol 144 (5) ◽  
pp. 295-304 ◽  
Author(s):  
Josh A. Honig ◽  
Megan F. Muehlbauer ◽  
John M. Capik ◽  
Christine Kubik ◽  
Jennifer N. Vaiciunas ◽  
...  
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Quantitative Trait ◽  
Genetic Linkage ◽  
Genetic Linkage Map ◽  
Restriction Site ◽  
Eastern United States ◽  
Double Digestion ◽  
Disease Pressure ◽  
Resistance Source

European hazelnut (Corylus avellana L.) is an economically important edible nut producing species, which ranked sixth in world tree nut production in 2016. European hazelnut production in the United States is primarily limited to the Willamette Valley of Oregon, and currently nonexistent in the eastern United States because of the presence of a devastating endemic disease, eastern filbert blight (EFB) caused by Anisogramma anomala (Peck) E. Muller. The primary commercial means of control of EFB to date is through the development and planting of genetically resistant european hazelnut cultivars, with an R-gene introduced from the obsolete, late-shedding pollinizer ‘Gasaway’. Although the ‘Gasaway’ resistance source provides protection against EFB in the Pacific northwestern United States (PNW), recent reports have shown that it is not effective in parts of the eastern United States. This may be in part because the identification and selection of ‘Gasaway’ and ‘Gasaway’-derived cultivars occurred in an environment (PNW) with limited genetic diversity of A. anomala. The objectives of the current research were to develop a genetic linkage map using double digestion restriction site associated DNA sequencing (ddRADseq) and identify quantitative trait loci (QTL) markers associated with EFB resistance from the resistant selection Rutgers H3R07P25 from southern Russia. A mapping population composed of 119 seedling trees was evaluated in a geographic location (New Jersey) where the EFB fungus is endemic, exhibits high disease pressure, and has a high level of genetic diversity. The completed genetic linkage map included a total of 2217 markers and spanned a total genetic distance of 1383.4 cM, with an average marker spacing of 0.65 cM. A single QTL region associated with EFB resistance from H3R07P25 was located on european hazelnut linkage group (LG) 2 and was responsible for 72.8% of the phenotypic variation observed in the study. Based on its LG placement, origin, and disease response in the field, this resistance source is different from the ‘Gasaway’ source located on LG6. The current results, in combination with results from previous research, indicate that the H3R07P25 source is likely exhibiting resistance to a broader range of naturally occurring A. anomala isolates. As such, H3R07P25 will be important for the development of new european hazelnut germplasm that combines EFB resistance from multiple sources in a gene pyramiding approach. Identification of EFB resistance in high disease pressure environments representing a diversity of A. anomala populations is likely a requirement for identifying plants expressing durable EFB resistance, which is a precursor to the development of a commercially viable european hazelnut industry in the eastern United States.

scholarly journals Genetic Diversity of Lowbush Blueberry throughout its U.S. Native Range in Managed and Non-managed Populations

2019 ◽  
Author(s):  
Lee Beers ◽  
Jeannie Rowland ◽  
Francis Drummond
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Polymerase Chain Reaction ◽  
Genetic Variation ◽  
Geographic Range ◽  
Eastern United States ◽  
Native Range ◽  
Chain Reaction ◽  
Lowbush Blueberry ◽  
Polymerase Chain

Expressed sequenced tagged-polymerase chain reaction (EST-PCR) molecular markers were used to evaluate the genetic diversity of lowbush blueberry across its geographic range and to compare genetic diversity among four paired managed/non-managed populations. Seventeen lowbush blueberry populations were sampled in a general north south transect throughout eastern United States with distances between 27 km to 1600 km separating populations. Results show that the majority of genetic variation is found within populations (75%) versus among populations (25%), and that each population was genetically unique (P ≤ 0.0001) with the exception of the Jonesboro, ME and Lubec, ME populations that were found not to be significantly different (P = 0.228). The effects of management for commercial fruit harvesting on genetic diversity were investigated in four locations in Maine with paired managed and non-managed populations. Significant differences were found between the populations indicating that commercial management influences the genetic diversity of lowbush blueberries in the landscape, despite the fact that planting does not occur; forests are harvested and the existing understory blueberry plants are what become established.

scholarly journals Genetic Diversity of Seven Deciduous Azalea Species (Rhododendron spp. section Pentanthera) Native to the Eastern United States

2008 ◽  
Vol 133 (3) ◽  
pp. 374-382 ◽  
Author(s):  
Matthew Chappell ◽  
Carol Robacker ◽  
Tracie M. Jenkins
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Genetic Variation ◽  
Gene Diversity ◽  
Interspecific Variation ◽  
Genetic Distances ◽  
Anthropogenic Activity ◽  
Group Method ◽  
Aflp Analysis ◽  
Eastern United States

Despite the ecologic and economic importance of native deciduous azaleas (Rhododendron L. section Pentanthera G. Don), our understanding of interspecific variation of North American deciduous azalea species comes principally from morphologic studies. Furthermore, little is known concerning intraspecific or interpopulation genetic variation. With ever-increasing loss and fragmentation of native azalea habitat in the eastern United States due to anthropogenic activity, it is imperative that an understanding of natural genetic variation among and within species and populations is acquired. The present study addresses questions of genetic diversity through the use of amplified fragment length polymorphism (AFLP) analysis. Twenty-five populations of seven species of native azalea were analyzed using three primer pairs that amplified a total of 417 bands. Based on analysis of molecular variance (AMOVA) and estimates of Nei's coefficients of gene diversity (H S, H T, and G ST), the majority of variation found in deciduous azalea occurs within populations. Variation both among species and among population was low, likely the effect of common ancestry as well as frequent introgression among members (and populations) of section Pentanthera. The latter was evident in four populations of R. prunifolium (Small) Millais and R. canescens (Michaux) Sweet that were highly related to R. austrinum (Small) Rehder and R. viscosum (L.) Torrey, respectively. Despite these outliers, most populations were grouped into species based on Nei's unbiased genetic distances viewed as an unweighted pair group method with arithmetic mean (UPGMA) phenogram. The significance of these results is discussed in relation to breeding in section Pentanthera.

scholarly journals Assessing Genetic Diversity and Population Structure of Kalmia latifolia L. in the Eastern United States: An Essential Step towards Breeding for Adaptability to Southeastern Environmental Conditions

2020 ◽  
Vol 12 (19) ◽  
pp. 8284
Author(s):  
He Li ◽  
Matthew Chappell ◽  
Donglin Zhang
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Genetic Differentiation ◽  
Environmental Conditions ◽  
Population Variation ◽  
Group Method ◽  
Eastern United States ◽  
Kalmia Latifolia ◽  
Essential Step ◽  
Genetic Diversity And Structure

Kalmia latifolia L. (mountain laurel), an attractive flowering shrub, is considered to be a high-value ornamental plant for the eastern United States. Limited information on the genetic diversity and structure of K. latifolia is available, which obstructs efficient germplasm utilization and breeding for adaptability to southeastern environmental conditions. In this study, the genetic diversity of 48 wild K. latifolia plants sampled from eight populations in the eastern U.S. was assessed using eight inter simple sequence repeat (ISSR) markers. A total of 116 bands were amplified, 90.52% of which (105) were polymorphic. A high level of genetic diversity at the species level was determined by Nei’s gene diversity (0.3089) and Shannon’s information index (0.4654), indicating that K. latifolia was able to adapt to environmental changes and thus was able to distribute over a wide latitudinal range. In terms of the distribution of genetic diversity, Nei’s genetic differentiation and analysis of molecular variance (AMOVA) showed 38.09% and 29.54% of diversity existed among populations, respectively, elucidating a low-to-moderate level of among-population genetic differentiation. Although a relatively large proportion of diversity was attributed to within-population variation, low diversity within populations (mean genetic diversity within populations (HS) = 0.19) was observed. Both STRUCTURE and unweighted pair group method with arithmetic mean (UPGMA) dendrograms exhibited the clustering of populations that inhabit the same geographic region, and four clusters correlated with four geographic regions, which might be attributed to insect pollination, small population size, and environmental conditions in different habitats. These results function as an essential step towards better conserving and utilizing wild K. latifolia resources, and hence promoting its genetic improvement and breeding for adaptability to southeastern environmental conditions.

scholarly journals Genetic Diversity of Lowbush Blueberry throughout the United States in Managed and Non-Managed Populations

Agriculture ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 113 ◽  
Author(s):  
Lee Beers ◽  
Lisa J. Rowland ◽  
Francis Drummond
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Polymerase Chain Reaction ◽  
The United States ◽  
Fruit Production ◽  
Geographic Range ◽  
Eastern United States ◽  
Chain Reaction ◽  
Lowbush Blueberry ◽  
Polymerase Chain

Expressed sequenced tagged-polymerase chain reaction (EST-PCR) molecular markers were used to evaluate the genetic diversity of lowbush blueberry across its geographic range and to compare diversity among four paired managed/non-managed populations. Seventeen populations were sampled in a north–south transect throughout the eastern United States with 27 km to 1600 km separating populations. The majority of genetic variation was found within populations (75%) with each population genetically unique (p ≤ 0.0001) with the exception of the Jonesboro, ME, and Lubec, ME, populations. The effects of management for commercial fruit harvesting on genetic diversity were investigated in four locations in Maine with paired managed and non-managed populations. Significant differences were found between the populations indicating that commercial management for fruit production influences the diversity of lowbush blueberries in the landscape, even though planting does not occur. Forests are harvested and the existing understory blueberry plants become established.

scholarly journals Phlox Species Show Quantitative and Qualitative Resistance to a Population of Powdery Mildew Isolates from the Eastern United States

2020 ◽  
Vol 110 (8) ◽  
pp. 1410-1418
Author(s):  
Coralie Farinas ◽  
Pablo S. Jourdan ◽  
Pierce A. Paul ◽  
Jason C. Slot ◽  
Margery L. Daughtrey ◽  
...  
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Powdery Mildew ◽  
Host Resistance ◽  
Phenotypic Diversity ◽  
Eastern United States ◽  
Significant Information ◽  
Mlst Analysis ◽  
Low Genetic Diversity ◽  
Qualitative Resistance

Ornamental plants in the genus Phlox are extensively planted in landscapes and home gardens around the world. A major limitation to a more widespread use of these plants is their susceptibility to powdery mildew (PM). In this study, we used multilocus sequence typing (MLST) analysis to gain insights into the population diversity of 32 Phlox PM pathogen (Golovinomyces magnicellulatus and Podosphaera sp.) isolates collected from the eastern United States and relate it to the ability to overcome host resistance. Low genetic diversity and a lack of structure were found within our population. Whole genome comparison of two isolates was used to support low genetic diversity evidence found with the MLST analysis. Recombination was suggested by the incongruences observed in the six phylogenetic trees generated from the housekeeping genes TEF-1α, CSI, ITS, IGS, H3, and TUB. Contrasting with low genetic diversity, we found high phenotypic diversity when using 10 of the 32 isolates to evaluate host resistance in four different Phlox species (P. paniculata ‘Dunbar Creek’, P. amoena OPGC 3598, P. glaberrima OPGC 3594, and P. subulata OPGC 4185) using in vitro bioassays. We observed quantitative and qualitative resistance in all Phlox species and a consistent low disease severity in our control, P. paniculata ‘Dunbar Creek’. Taken together, the results generated in this study constitute a robust screening of popular Phlox germplasm that can be incorporated into breeding programs for PM resistance and provides significant information on the evolution of PM pathogens.

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