1,720,973 research outputs found
Microsatellite fingerprinting of an indigenous grapevine collection.
No full textWe report our study on genetic diversity and relationships in an endangered grape germplasm collection using polymorphism at 30 microsatellite loci. A germplasm safeguard programme was set up of grapevine varieties considered as indigenous to North-Eastern Italy. In Italy indeed, as in other Mediterranean countries, grapevine (Vitis vinifera L.) used to be characterized by the diffuse presence of indigenous cultivars, originated through centuries of natural and human selection (Martin et al. 2003, Snoussi et al. 2004). To ensure that allele size of SSRs was properly scored, the SSR marker system relied on a Vitis vinifera microsatellite genotype database. For this purpose we utilized the GENRES#081 (European Network for Grapevine Genetic Resources Conservation and Characterization; This et al. 2004). The genetic profiles of 19 grapevine indigenous varieties, together with seven international ones taken as reference, were searched for possible parentage relationships and several cases of suspected synonyms have been investigated. In the indigenous varieties the number of alleles per locus ranged from two at UDV109, VVIQ61, VVIU37 and VVIV16 loci, to ten at VVMD7 locus, with an average of 4.6 alleles per locus. The native germplasm displayed a greater diversity with an higher proportion of unique alleles compared to international cultivars. This is probably due to a past contribution of wild grapevine to the cultivated genepool. Furthermore all native varieties clustered in the same branch of the UPGMA phenogram thus confirming their local origin. In this research the majority of local cultivars were demonstrated to constitute an independent source of genetic variation, and therefore a possible valuable resource of interesting genetic traits for breeders
Genetic variability and biodiversity conservation of an indigenous grapevine germplasm collection: perspective from nuclear and chloroplast SSR variation.
No full textGenepool variation and phylogenetic relationships of an indigenous north-east Italian grapevine collection revealed by nuclear and chloroplast SSRs.
No full textA germplasm safeguard programme was set up with 19 grapevine varieties considered as indigenous to northeastern
Italy. To better estimate how genetic structure can be used to obtain a conservation perspective of local varieties,
genetic variability was examined at 30 nuclear and 3 chloroplast polymorphic microsatellite loci in the native varieties plus 7 European cultivars taken as reference. The genetic profiles of all the cultivars were searched for possible parentage relationships and several suspected cases of the same variety having different names were investigated. The alleles shared at the loci suggest a parent–offspring relationship between Merlot and Cabernet Franc, ‘Gruaja’ and ‘Negrara Veronese’, and Marzemina Nera and Marzemina Bianca. Alleles at the 30 nuclear loci are consistent with Raboso Veronese being the progeny of Marzemina Bianca and Raboso Piave. Chloroplast-specific haplotypes were singled out for the first time in this indigenous germplasm and should be considered typical of the region. It is hypothesized that there are many specific haplotypes for the local varieties due to a past contribution of wild grapevine to the cultivated gene pool. The majority of investigated cultivars were demonstrated to constitute an independent source of genetic variation, and therefore a possible valuable resource of genetic traits for breeders
Valorization of a Veneto grapevine germoplasm collection by molecular characterization and biochemical analysis of resveratrol compounds
No full textGrapevine is the most important perennial crop worldwide. The world’s collections of grape plant material are estimated to contain about 12000–15.000 cultivars. Many of these are ancient and autochthonous cultivars still not registered in the ampelographic national catalogues and therefore risking the extinction. In order to safeguard this germplasm a correct classification solving the problems of synonymous and homonymous in the cultivar designations is requested.
The identification and comparison of plant material by ampelographic methods is liable to misinterpretations, while DNA-based markers provide a more reliable alternative for cultivar identification. To preserve the genetic variability of local germplasm we initiate the characterization of 30 North-Eastern cultivars at 23 microsatellite loci. The markers were proved to be informative in the grapevine cultivars. The genetic profiles of all 30 cultivars were searched for possible parent-offspring groups and several cases of suspected synonyms have been investigated.
The valorization of this germplasm was implemented by biochemical analysis of resveratrol (trans-3, 4 , 5-trihydroxystilbene) content. This stilbenic compound is a phytoalexin protecting grapevine against fungal infections. The recent years have also witnessed intense research aimed to clarify the role of stilbenes (that are also present in wines) and, among them, resveratrol, in human health because of their protective effects against cardiac decompensation and cancer. The potential therapeutic value of resveratrol has stimulated research activities on the occurrence of this molecules in grapes and wines
Biodiversity of local Italian grapevine detected by SSR markers.
No full textGrapevine cultivation is an age-old tradition in the Veneto region of Italy where many ancient cultivars are still grown. Some of these cultivars are recognised as producing important Controlled Designations of Origin (D.O.C.) wines, while other local types have been lost through substitution by international cultivars. Despite the large number of ancient cultivars present in the Veneto region, many are not registered in the Italian Ampelographic Catalogue and therefore risk extinction. Moreover, synonyms and homonyms have often become popular at local level, thus rendering correct varietal identification tricky. Our aim was to characterize ancient local cultivars to preserve the germoplasm and investigate their genetic relationships. Genetic variability was assessed in 18 local varieties using nuclear simple sequence repeat (SSR) markers to identify the most similar groups and verify if these groupings are in agreement with the known history of the cultivars
Identification of Salix L. entities by DNA barcoding.
No full textFollowing the sequencing of a growing number of plant genomes and with the availability of more and more powerful computational tools, DNA sequences are becoming the major source of information in understanding the evolutionary and genetic relationship among plant species. The importance of a comparative sequence analysis is clearly evident in studies aimed at clarifying the taxonomic and phylogenetic relationships at interspecific level. Since 2003 several authors proposed and demonstrated that the nucleotide content of a single gene can be sufficient for the discrimination and the identification of animal species. The experimental reliability and the general applicability of this approach, known as “DNA barcoding”, has been first assessed using the mitochondrial gene CO1 encoding for the subunit I of the cytochrome oxydase .The term “DNA barcoding” refers to a DNA-sequence based identification system that may be constructed of several loci used together as complementary unit to define a specific haplotype. A species can thus be unequivocally identified on the basis of single nucleotide polymorphisms (SNPs) or insertions/deletions (In/Dels) in the most conserved regions of one or a few selected genes. A DNA barcoding approach based on mitochondrial genes is not feasible in plants because of their much slower rate of evolution compared to animals.. This research was aimed at developing molecular diagnostic tests able to screen the plant biodiversity and univocally identify species belonging to the Salix L. genus. For this purpose we assessed the level of sequence divergence (SNP and In/del polymorphisms) among 22 willow species in two chloroplast putative barcode loci to determine which of them maximize species identification when combined as a barcode.
Willow species belonging to Humboldtiana and Salix subgenera were clustered apart, supporting species separation on the basis of bio-geographical and morphological traits, whereas species of subgenera Caprisalix and Chamaetia were unrecognizable on the basis of two chloroplast intergene spacers, this is probably due to their frequent hybrid origin. Nuclear barcode sequences, able to identify recombination events have to be evaluated
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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