Search results for "hybrid"
showing 10 items of 2143 documents
Phylogenetic evidence for hybrid origins of asexual lineages in an aphid species
2003
International audience; Understanding the mode of origin of asexuality is central to ongoing debates concerning the evolution and maintenance of sexual reproduction in eukaryotes. This is because it has profound consequences for patterns of genetic diversity and ecological adaptability of asexual lineages, hence on the outcome of competition with sexual relatives both in short and longer terms. Among the possible routes to asexuality, hybridization is a very common mechanism in animals and plants. Aphids present frequent transitions from their ancestral reproductive mode (cyclical parthenogenesis) to permanent asexuality, but the mode of origin of asexual lineages is generally not known bec…
Transcriptome and proteome analysis of Pinctada margaritifera calcifying mantle and shell: focus on biomineralization
2010
Abstract Background The shell of the pearl-producing bivalve Pinctada margaritifera is composed of an organic cell-free matrix that plays a key role in the dynamic process of biologically-controlled biomineralization. In order to increase genomic resources and identify shell matrix proteins implicated in biomineralization in P. margaritifera, high-throughput Expressed Sequence Tag (EST) pyrosequencing was undertaken on the calcifying mantle, combined with a proteomic analysis of the shell. Results We report the functional analysis of 276 738 sequences, leading to the constitution of an unprecedented catalog of 82 P. margaritifera biomineralization-related mantle protein sequences. Component…
Emergence and growth of hybrids between Brassica napus and Raphanus raphanistrum.
2003
Summary • Risk assessment studies of transgenic crops have recently brought evidence of a low spontaneous hybridization frequency of Brassica napus with Raphanus raphanistrum. The fate of the first generation hybrids is crucial to determine the initial rate of spread of transgenes. • This work aims to compare the fitness components of parents and F1 hybrids at the first step of the life cycle. The ability to emerge, establish seedling, cover the soil and develop adult plant was examined in controlled and field conditions, alone or in competition. • The F1 hybrids showed a lower seedling emergence, a significant delay of emergence, and a lower survival than for both parents. Rosette diameter…
Seed germination and seedling allogamy in Rosmarinus officinalis: the costs of inbreeding.
2018
Self‐pollination by geitonogamy is likely in self‐compatible plants that simultaneously expose a large number of flowers to pollinators. However, progeny of these plants is often highly allogamous. Although mechanisms to increase cross‐pollination have been identified and studied, their relative importance has rarely been addressed simultaneously in plant populations. We used Rosmarinus officinalis to explore factors that influence the probability of self‐fertilisation due to geitonogamy or that purge its consequences, focusing on their effects on seed germination and allogamy rate. We experimentally tested the effect of geitonogamy on the proportion of filled seeds and how it influences ge…
Inflorescence scents of Calendula maritima, C. suffruticosa subsp. fulgida, and their hybrid
2018
Premise of research. Hybridization is an important driver of plant evolutionary processes. By attracting the same pollinators to different species, floral scents may be involved in the formation of hybrids and breakdown of species boundaries. In contrast, by attracting a different suite of pollinators to hybrids and their parents, floral scents are believed to contribute to speciation processes initiated by hybridization events. Scents may or may not differ between the hybrids and their parents, but little is known about the scent chemistry of parental species and their hybrids. Methodology. We studied the inflorescence scents of parental Calendula maritima and C. suffruticosa subsp. fulgid…
Identity of the Calcarata species complex in Viola sect. Melanium (Violaceae)
2020
The Calcarata species complex in Viola sect. Melanium (Violaceae) is a group of species from Italy and neighbouring islands. The complex is of considerable evolutionary interest because several hypotheses about hybrid speciation within the group have been previously proposed. Because the Calcarata complex is not well characterized morphologically, we used 142 samples representing 92 (of c. 120) species of V. sect. Melanium plus three outgroup species. Nuclear ITS and ETS and plastid trnS–trnG intergenic spacer sequences were analysed to test the monophyly of the Calcarata complex and to infer relationships among the constituent species. Both nuclear and plastid sequences resulted in very li…
Impact of vector dispersal and host-plant fidelity on the dissemination of an emerging plant pathogen
2012
International audience; Dissemination of vector-transmitted pathogens depend on the survival and dispersal of the vector and the vector's ability to transmit the pathogen, while the host range of vector and pathogen determine the breath of transmission possibilities. In this study, we address how the interaction between dispersal and plant fidelities of a pathogen (stolbur phytoplasma tuf-a) and its vector (Hyalesthes obsoletus: Cixiidae) affect the emergence of the pathogen. Using genetic markers, we analysed the geographic origin and range expansion of both organisms in Western Europe and, specifically, whether the pathogen's dissemination in the northern range is caused by resident vecto…
Regulation of reactive oxygen species production by a 14-3-3 protein in elicited tobacco cells.
2007
International audience; The regulation of the system responsible for the production of reactive oxygen species (ROS) during plant–microorganism interaction is still largely unknown. The protein NtrbohD has been recently demonstrated as the plasma membrane oxidase responsible for ROS production in elicited tobacco cells. Here, its C-terminus part was used as a bait in a two-hybrid screen in order to identify putative regulators of this system. This led to the isolation of a cDNA coding for a member of the 14-3-3 protein family. The corresponding transcript was induced after infiltration of tobacco leaves with the fungal elicitor cryptogein. Tobacco cells transformed with an antisense constru…
Genetic admixture despite ecological segregation in a North African sparrow hybrid zone (Aves, Passeriformes, Passer domesticus × Passer hispaniolens…
2019
Under different environmental conditions, hybridization between the same species might result in different patterns of genetic admixture. Particularly, species pairs with large distribution ranges and long evolutionary history may have experienced several independent hybridization events over time in different zones of overlap. In birds, the diverse hybrid populations of the house sparrow (Passer domesticus) and the Spanish sparrow (Passer hispaniolensis) provide a striking example. Throughout their range of sympatry, these two species do not regularly interbreed; however, a stabilized hybrid form (Passer italiae) exists on the Italian Peninsula and on several Mediterranean islands. The spa…
Pseudomonas salomonii sp. nov., pathogenic on garlic, and Pseudomonas palleroniara sp. nov., isolated from rice
2002
International audience; A total of 26 strains, including 15 strains isolated from garlic plants with the typical symptoms of 'Café au lait' disease and 11 strains isolated from diseased or healthy rice seeds and sheaths infested by Pseudomonas fuscovaginae, were compared with 70 type or reference strains of oxidase-positive pathogenic or non-pathogenic fluorescent pseudomonads. The strains were characterized by using a polyphasic taxonomic approach. Numerical taxonomy of phenotypic characteristics showed that the garlic and rice strains were related to each other. However, they clustered into separate phenons, distinct from those of the other strains tested, and were different in several nu…