scholarly journals Grape Phylloxera Genetic Structure Reveals Root–Leaf Migration within Commercial Vineyards

Insects ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 697
Author(s):  
Jurrian Wilmink ◽  
Michael Breuer ◽  
Astrid Forneck
Keyword(s):  
Life Cycle ◽  
Genetic Structure ◽  
Genotypic Diversity ◽  
Vegetation Period ◽  
Population Bottlenecks ◽  
Grape Phylloxera ◽  
Sexual Recombination ◽  
Population Structures ◽  
Natural Infestation ◽  
Root Feeding

Depending on their life cycle, grape phylloxera (Daktulosphaira vitifoliae Fitch) leaf-feeding populations are initiated through asexually produced offspring or sexual recombination. The vine’s initial foliar larvae may originate from root-feeding phylloxera or wind-drifted foliar larvae from other habitats. Though some studies have reported phylloxera leaf-feeding in commercial vineyards, it is still unclear if they are genetically distinct from the population structure of these two sources. Using seven SSR-markers, this study analyzed the genetic structure of phylloxera populations in commercial vineyards with different natural infestation scenarios and that of single-plant insect systems that exclude infestation by wind-drifted larvae. We saw that during the vegetation period, phylloxera populations predominately go through their asexual life cycle to migrate from roots to leaves. We provided evidence that such migrations do not exclusively occur through wind-drifted foliar populations from rootstock vines in abandoned thickets, but that root populations within commercial vineyards also migrate to establish V. vinifera leaf populations. Whereas the former scenario generates foliar populations with high genotypic diversity, the latter produces population bottlenecks through founder effects or phylloxera biotype selection pressure. We finally compared these population structures with those of populations in their native habitat in North America, using four microsatellite markers.

Reproductive mode of grape phylloxera (Daktulosphaira vitifoliae, Homoptera: Phylloxeridae) in Europe: molecular evidence for predominantly asexual populations and a lack of gene flow between them

Genome ◽  
2006 ◽  
Vol 49 (6) ◽  
pp. 678-687 ◽  
Author(s):  
Sonja Vorwerk ◽  
Astrid Forneck
Keyword(s):  
Genetic Structure ◽  
Reproductive Mode ◽  
Genotypic Diversity ◽  
Molecular Evidence ◽  
Main Mode ◽  
Daktulosphaira Vitifoliae ◽  
Grape Phylloxera ◽  
Multiple Introductions ◽  
Important Pest ◽  
Asexual Populations

The genetic structure of European grape phylloxera populations, Daktulosphaira vitifoliae (Homoptera: Phylloxeridae), was analyzed using 6 polymorphic microsatellite markers. Genetic diversity data of 6 populations originating from northern and southern European viticultural regions was assessed for geographic differences, and the structure of 2 additional populations was examined in more detail, focusing on specific host plant and habitat charac ter istics. To test for "signatures" of clonal reproduction, different population genetic measures were applied to the data obtained from these populations. A total of 195 multilocus genotypes were detected in 360 individuals tested. Significant deviations from Hardy–Weinberg equilibrium, negative FISvalues (from –0.148 to –0.658 per population), and the presence of multicopy genotypes revealed that the current major reproductive mode at each of the locations tested was asexual. The high genotypic diversity detected within and among populations, however, together with the occurrence of unique D. vitifoliae genotypes, indicates sexual recombination events took place, probably prior to the multiple introductions into Europe. The absence of overlapping genotypes between the sampling sites suggests low migration rates among the populations studied and implies that the main mode of insect dispersal is through infested plant material carried by human agency. The specific features of European D. vitifoliae habitats are illustrated to discuss the role of habitat and life cycle in the genetic structure of this globally important pest aphid species.Key words: Daktulosphaira vitifoliae, microsatellites, genetic structure, asexual reproduction, parthenogenesis.

Population genetic structure in duckweed (Lemna minor, Lemnaceae)

1996 ◽  
Vol 74 (2) ◽  
pp. 222-230 ◽  
Author(s):  
Christopher T. Cole ◽  
Martin I. Voskuil
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Population Genetic ◽  
Lemna Minor ◽  
Vegetative Reproduction ◽  
Low Frequency ◽  
Morphological Differentiation ◽  
Genotypic Diversity ◽  
Allozyme Variation ◽  
Low Levels

Allozyme variation in 11 Minnesota populations of Lemna minor L. was studied, using 11 enzyme systems, resolving 16 putative loci from 285 plants. Significant deviations from Hardy–Weinberg frequencies occurred in several populations that had excesses of heterozygotes at several loci. While genotypic diversity and evenness measures are similar to other vegetatively reproducing plants (D = 0.541, E = 0.607), very few multilocus genotypes per population were found (mean = 4.0). Substantial population structure was evident (FST = 0.407), apparently reflecting low levels of gene flow (Nm = 0.30) despite the capacity of this species for dispersal of plantlets. This low level of gene flow and apparent low frequency of sexual reproduction has produced substantial levels of genetic divergence among populations, despite an absence of morphological differentiation. Keywords: allozymes, genetic structure, hydrophily, Lemna, vegetative dispersal, vegetative reproduction.

Seasonal life cycle of Holotrichia longipennis (Blanchard ) (Coleoptera: Scarabaeidae: Melolonthinae): a serious foliage and root feeding pest in India

2016 ◽  
Vol 44 (5) ◽  
pp. 615-629
Author(s):  
Mandeep Pathania ◽  
Ravinder Singh Chandel ◽  
Kuldeep Singh Verma ◽  
Pawan Kumar Mehta
Keyword(s):  
Life Cycle ◽  
Root Feeding ◽  
Holotrichia Longipennis

scholarly journals Genetic structure and admixture between the Posavina and Croatian Coldblood in contrast to Lipizzan horse from Croatia

2013 ◽  
Vol 58 (No. 2) ◽  
pp. 71-78 ◽  
Author(s):  
A. Galov ◽  
K. Byrne ◽  
T. Gomerčić ◽  
M. Duras ◽  
H. Arbanasić ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Allele Frequency Distribution ◽  
Ratio Test ◽  
Genetic Introgression ◽  
Population Bottlenecks ◽  
Mode Shift ◽  
Heterozygosity Excess ◽  
Distribution Mode ◽  
Distinct Genetic Group ◽  
Breeding Schemes

The Posavina and Croatian Coldblood are Croatian autochthonous horse breeds with interwoven breeding histories for which studbooks have only recently been established. The Lipizzan breed has the oldest formalized breeding and no record of recent genetic introgression from other breeds in Croatia. We analyzed the genetic structure, interbreeding, and breed characteristics by genotyping nine dinucleotide microsatellite loci for 53 Posavina, 37 Croatian Coldblood, and 33 Lipizzan horses and showed that differing breeding schemes and histories have had a strong and measurable impact on the population genetic structure within and between the three breeds. A Bayesian clustering method demonstrated that two population clusters best explain the genetic structure. Samples from the pre-defined breeds of the Posavina and Croatian Coldblood were assigned to a separate genetic cluster, while Lipizzan specimens were assigned to another distinct genetic group. Twelve samples of the Posavina/Croatian Coldblood cluster (13%) showed admixed ancestry with Lipizzan horses. A test for heterozygosity excess, allele frequency distribution mode-shift, and M-ratio test were used to detect genetic evidence of recent population bottlenecks, none of which provided evidence for bottlenecks in the Posavina and Croatian Coldblood populations. In contrast, although somewhat ambiguous, evidence suggests a genetic bottleneck in the Lipizzan population in Croatia.

Genetic differences within natural and planted stands of Quercus petraea

2011 ◽  
Vol 6 (4) ◽  
pp. 597-605 ◽  
Author(s):  
Jiří Dostálek ◽  
Tomáš Frantík ◽  
Miroslava Lukášová
Keyword(s):  
Genetic Structure ◽  
Genetic Differentiation ◽  
Spatial Genetic Structure ◽  
Quercus Petraea ◽  
Genetic Differences ◽  
Sessile Oak ◽  
Population Structures ◽  
Nuclear Microsatellite ◽  
The Impact ◽  
Two Populations

AbstractFive sessile oak [Quercus petraea (Matt.) Liebl.] stands from the Czech Republic were studied to learn about the impact of different types of forest management regimes on the genetic differences among tree populations and on population structures. One population had not been markedly affected by human activity, two populations represented unplanted stands that were extensively managed for a long period of time using the coppice system, and two populations were planted stands. Approximately 100 trees from each stand were mapped and subsequently genotyped using 10 nuclear microsatellite loci. We determined the spatial genetic structure of each population and the genetic differentiation among the populations. We found that: (i) the populations were genetically differentiated, but the differences between the unplanted and planted stands were not markedly significant; (ii) the genetic differentiation among the populations depended on the geographical distribution of the populations; (iii) within unplanted stands, a strong spatial genetic structure was seen; and (iv) within planted stands, no spatial genetic structure was observed. Our findings implies that the analysis of spatial genetic structure of the sessile oak forest stand can help reveal and determine its origin.

scholarly journals Fine-Scale Genetic Structure of Monilinia fructicola During Brown Rot Epidemics Within Individual Peach Tree Canopies

2015 ◽  
Vol 105 (4) ◽  
pp. 542-549 ◽  
Author(s):  
S. E. Everhart ◽  
H. Scherm
Keyword(s):  
Genetic Structure ◽  
Brown Rot ◽  
Genotypic Diversity ◽  
Fruit Rot ◽  
Monilinia Fructicola ◽  
Peach Tree ◽  
Fine Scale ◽  
High Genetic Diversity ◽  
Pathogen Diversity ◽  
Tree Canopies

The purpose of this study was to determine the fine-scale genetic structure of populations of the brown rot pathogen Monilinia fructicola within individual peach tree canopies to better understand within-tree plant pathogen diversity and to complement previous work on spatiotemporal development of brown rot disease at the canopy level. Across 3 years in a total of six trees, we monitored disease development, collected isolates from every M. fructicola symptom during the course of the season, and created high-resolution three-dimensional maps of all symptom and isolate locations within individual canopies using an electromagnetic digitizer. Each canopy population (65 to 173 isolates per tree) was characterized using a set of 13 microsatellite markers and analyzed for evidence of spatial genetic autocorrelation among isolates during the epidemic phase of the disease. Results showed high genetic diversity (average uh = 0.529) and high genotypic diversity (average D = 0.928) within canopies. The percentage of unique multilocus genotypes within trees was greater for blossom blight isolates (78.2%) than for fruit rot isolates (51.3%), indicating a greater contribution of clonal reproduction during the preharvest epidemic. For fruit rot isolates, between 54.2 and 81.7% of isolates were contained in one to four dominant clonal genotypes per tree having at least 10 members. All six fruit rot populations showed positive and significant spatial genetic autocorrelation for distance classes between 0.37 and 1.48 m. Despite high levels of within-tree pathogen diversity, the contribution of locally available inoculum combined with short-distance dispersal is likely the main factor generating clonal population foci and associated spatial genetic clustering within trees.

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