1,720,989 research outputs found
Cytogenetic characterization by in situ hybridization techniques and molecular analysis of 5S rRNA genes of the European hazelnut (Corylus avellana).
No full textCorylus avellana L, the European hazelnut, is widespread in Europe where it has been cultivated for centuries. Despite progress in genetics most of the cytogenetic aspects of this species have been overlooked. The aim of this study was to fill in this gap and obtain basic information on the chromosome structure of this species. Karyomorphological analysis confirmed the chromosome number 2n=22 and showed that, despite their apparent uniformity, the chromosomes could be separated into three groups of different size: large (L), medium (M) and small (S) chromosomes. As a first step towards the physical mapping of the hazelnut chromosomes we applied FISH to localize the position of rRNA genes (rDNA). The sites of 45S and 5S rDNA enabled us to identify two chromosome pairs belonging, respectively, to the L and S groups. The self GISH procedure revealed that repetitive DNA is concentrated in the pericentromeric regions of the chromosomes, as with other species with rather small genomes. The analysis of 5S rDNA repeats offered additional information on the hazelnut genome by obtaining the whole sequence of the transcribed region so far unpublished. The overall results constitute a substantial advance in hazelnut cytogenetics. Further investigation of other Corylus species could be an effective approach to understanding the phylogenesis of the genus and resolving taxonomic problems
Dynamics of 5S rDNA in Medicago truncatula: chromosome distribution, sequence analysis and molecular phylogeny.
No full textthe results of this study induce to consider the spacer regions an important source of information to explore the molecular evolution of genomes of Medicago species
i primi risultati della citogenetica molecolare nello studio della biodiversità. Il caso della vite
No full textIsolation of candidate genes for apomixis in Poa pratensis L.
No full textThe essential feature of apomixis is that an embryo is formed autonomously by parthenogenesis from an unreduced egg of an embryo sac generated through apomeiosis. The genetic constitution of the offspring is, therefore, usually identical to the maternal parent, a trait of great interest to plant breeders. If apomixis were well understood and harnessed, it could be exploited to indefinitely propagate superior hybrids or specific genotypes bearing complex gene sets. A fundamental contribution to the understanding of the genetic control of the apomictic pathway could be provided by a deep knowledge of molecular mechanisms that regulate the reproductive events. In Poa pratensis the cDNA-AFLP method of mRNA profiling allowed us to visualize a total of 2248 transcript-derived fragments and to isolate 179 sequences that differed qualitatively or quantitatively between apomictic and sexual genotypes at the time of flowering when the primary stages of apomixis occur. Three ESTs were chosen for further molecular characterization because of their cDNA-AFLP expression pattern and BLAST information retrieval. The full-lengths of the newly isolated genes were recovered by RACE and their temporal expression patterns were assessed by RT- PCR. Their putative role in cell signaling transduction cascades and trafficking events required during sporogenesis, gametogenesis and embryogenesis in plants is reported and discussed
Genetic and reproductive diversity within and among kentucky bluegrass (Poa pratensis L.) Worldwide accessions. XXVI Eucarpia Fodder Crops and Amenity Grasses meeting.
No full textAnalysis of DNA methylation in rapeseed (Brassica napus var. oleifera Del.) under salt stress based on methylation-sensitive amplified polymorphism
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Agronomic, chemical and genetic variability of saffron (Crocus sativus L.) of different origin by LC-UV–vis-DAD and AFLP analyses
No full textThe identification of a bi-univocal corre- spondence between geographical origin of saffron (Crocus sativus L.) and the composition of its stigmas has recently been the subject of many research papers, which have focused on the analysis of the differences among the so called ‘‘minor components’’, such as flavonoids and volatiles, in the secondary metabolic pattern of this spice. Saffron pigments (crocetin esters), on the other hand, constitute the majority of the metabolites found in its stigmas, and their spectrophotometric measurement is still used as an official method to determine the quality of the spice in terms of coloring power. To our knowledge, no attempts have been made to find a correspondence between the geographical origin of different saffron samples and their morphological traits and pigments pattern. In this paper, we have demonstrated that saffron corms of different origins, grown in the same experimental field, produce daughter corms with different dimensions and still produce stigma samples with different pigment profiles. Furthermore, daughter corm dimensions and pigment profile even more so, may be related to the origin of the sample, and therefore pigments can be used as chemotaxonomic markers. Compositional analyses results were corroborated by genetic data obtained using AFLP molecular markers
Exposure to cadmium-contaminated soils increases allergenicity of 1 Poa annua L. pollen.
No full textBackground: Pollution is considered as one main cause for the increase of allergic diseases. Air pollutants may cause and worsen airway diseases and are probably able to make pollen allergens more aggressive. Previous studies looked at traffic- related air pollution, but no data about the effects of polluted soils on pollen aller- gens are available. We aimed to assess the effects of plant exposure to cadmium- contaminated soil on allergenicity of the annual blue grass, Poa annua L, pollen. Methods: Poa plants were grown in soil contaminated or not contaminated (control) with cadmium. At flowering, mature pollen was analyzed by microscopy, to calcu- late the percentage of pollen grains releasing cytoplasmic granules, and by proteo- mic techniques to analyze allergen proteins. Allergens were identified by sera from grass pollen–allergic patients and by mass spectrometry.
Results: Pollen from Cd-exposed plants released a higher amount of allergenic pro- teins than control plants. Moreover, Cd-exposed pollen released allergens-containing cytoplasmic grains much more promptly than control pollen. Group 1 and 5 aller- gens, the major grass pollen allergens, were detected both in control and Cd-exposed extracts. These were the only allergens reacting with patient’s sera in control pollen, whereas additional proteins strengthening the signal in the gel region reacting with patient’s sera were present in Cd-exposed pollen. These included a pectinesterase, a lipase, a nuclease, and a secretory peroxydase. Moreover, a PR3 class I chitinase- like protein was also immunodetected in exposed plants.
Conclusion: Pollen content of plants grown in Cd-contaminated soils is more easily released in the environment and also shows an increased propensity to bind specific IgE
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