26,643 research outputs found
Changing of flight phenology and ecotype expansion of the European corn borer (Ostrinia nubilalis Hbn.) in Hungary Part
The studies aimed to acquire the widest possible information on the annual flight in Hungary of the European corn borer (ECB), Ostrinia nubilalis Hübner (Lepidoptera: Pyralidae). The investigations used biomathematical (Part 1) and graphical (Part 2) evaluation to document changes in the individual population number.The study was conducted in Hungary using ECB moth capture records from the Plant Protection Information System black light trap system (1991–2004). We have drawn conclusions on the appearance of annual flights and the tendency of alterations in flight direction by means of light trap results in four different areas in Hungary. We calculated the flight peak quotients, the individual population numbers of the second flight peak, the distinctions of individual numbers of two flight peaks in this part.As previously published, alterations in flight direction of ECB flights began at different times in Hungary. In the current study, a gradual disappearance of the univoltine ecotype and gradual appearance of the bivoltine ecotype ECB in Hungary is confirmed by the data obtained between 1991–2004. Flight peak quotients and data concerning the second flight peak have confirmed change this process, too: the appearance of a second flight peak in Northwestern Hungary from 1995–1996 (FP = 1.27), the more significant appearance of flights in August in Western Hungary (FP = 1.05) and Northeastern Hungary (FP = 1.45), and a three and four times more individual number of the second flight peak in Southeastern Hungary (FP = 3.44). Flight peak quotients, individual population numbers of the second flight peak, the tendency towards a difference in population number of the two peaks, and size of increase of these values demonstrates the southeastern-northwestern presence of the bivoltine ecotype in Hungary
The role of the Cucumber mosaic virus 2b protein in viral movement and symptom induction
The Cucumber mosaic virus (CMV) 2b protein is a counter-defense factor and symptom determinant. Conserved domains in the 2b protein sequence were mutated in the 2b gene of strain Fny-CMV. The effects of these mutations were assessed by infection of Nicotiana tabacum, N. benthamiana, and Arabidopsis thaliana (ecotype Col-0) with mutant viruses and by expression of mutant 2b transgenes in A. thaliana. We confirmed that two nuclear localization signals were required for symptom induction and found that the N-terminal domain was essential for symptom induction. The C-terminal domain and two serine residues within a putative phosphorylation domain modulated symptom severity. Further infection studies were conducted using Fny-CMVΔ2b, a mutant that cannot express the 2b protein and that induces no symptoms in N. tabacum, N. benthamiana, or A. thaliana ecotype Col-0. Surprisingly, in plants of A. thaliana ecotype C24, Fny-CMVΔ2b induced severe symptoms similar to those induced by the wild-type virus. However, C24 plants infected with the mutant virus recovered from disease while those infected with the wild-type virus did not. Expression of 2b transgenes from either Fny-CMV or from LS-CMV (a mild strain) in Col-0 plants enhanced systemic movement of Fny-CMVΔ2b and permitted symptom induction by Fny-CMVΔ2b. Taken together, the results indicate that the 2b protein itself is an important symptom determinant in certain hosts. However, they also suggest that the protein may somehow synergize symptom induction by other CMV-encoded factors
Changes in Antioxidant Enzymes Activity and Oxidative Damage in Four Argania spinosa Ecotypes Under Water Stress Conditions
_Argania spinosa_ L. Skell, a tree endemic of Morocco, grows in semiarid and arid areas. Biochemical response to drought in four ecotypes of the _A. spinosa_ was compared. Choice of ecotypes was based on evident differences in geographical features in south-west Morocco: two coastal ecotypes (Essaouira and Agadir) and two paralittorale ecotypes (Aoulouz and Lakhssas). Lipid peroxidation (malonyldialdehyde (MDA)), content of endogenous hydrogen peroxide (H2O2) and antioxidant enzyme system (Catalase (CAT), Ascorbate peroxidase (APX), Total peroxidase (POD) and Polyphenoloxidase (PPO) were measured in control (100% relative humidity (RH) at field capacity (FC)) and water-stressed plants (50 and 25% RH at FC). For all ecotypes, drought stress significantly increased the contents of MDA and H2O2 and an ecotype effect was noted. According Two-way ANOVA analysis, the ecotype x watering regime interaction was highly significant. We found an increase in the activities of the four ROS-scavenging enzymes and an ecotype effect was noted. Ecotype x watering regime interaction shows that only the CAT and APX activities were significant. Highest values of POD and PPO activities were found in both paralittorale ecotypes. Increase in antioxidant enzyme activities appears to be an adaptive response to restore the reactive oxygen species in their homeostasis. The four study ecotypes were separated by two discriminant functions obtained by canonical discriminant analysis. Coastal ecotypes are separated from the paralittorale ecotypes mainly by POD and PPO activities and MDA content
Taxonomical revision of the Late Würm Sorex (Mammalia, Insectivora) remains of Hungary, for proving the presence of an alpine ecotype in the Pilisszántó Horizon
Fossil bone assemblages of 14 localities, ranged in the Pilisszántó Horizon (Late Würm), are stored in the collection of the Geological Museum of Hungary and Hungarian Natural History Museum. Sorex araneus findings were reported from five of them (Balla Cave, Bivak Cave, Peskő Cave, Petényi Cave, Pilisszántó Shelter). Taxonomic revision of S. araneus showed that several specimens belong to S. alpinus in Balla Cave and Petényi Cave. The presence of this form, supported by other Boreo-Alpine fauna elements, indicates not only a significantly cold climate in the Pilisszántó Horizon, but the development of a special ecotype in the named localities. However. as the sites are only 400–800 m above see level, mountainous relief and periglacial climate yielded open mountain vegetation above the zone of pine forests
Recommended from our members
Large-effect flowering time mutations reveal conditionally adaptive paths through fitness landscapes in Arabidopsis thaliana.
Contrary to previous assumptions that most mutations are deleterious, there is increasing evidence for persistence of large-effect mutations in natural populations. A possible explanation for these observations is that mutant phenotypes and fitness may depend upon the specific environmental conditions to which a mutant is exposed. Here, we tested this hypothesis by growing large-effect flowering time mutants of Arabidopsis thaliana in multiple field sites and seasons to quantify their fitness effects in realistic natural conditions. By constructing environment-specific fitness landscapes based on flowering time and branching architecture, we observed that a subset of mutations increased fitness, but only in specific environments. These mutations increased fitness via different paths: through shifting flowering time, branching, or both. Branching was under stronger selection, but flowering time was more genetically variable, pointing to the importance of indirect selection on mutations through their pleiotropic effects on multiple phenotypes. Finally, mutations in hub genes with greater connectedness in their regulatory networks had greater effects on both phenotypes and fitness. Together, these findings indicate that large-effect mutations may persist in populations because they influence traits that are adaptive only under specific environmental conditions. Understanding their evolutionary dynamics therefore requires measuring their effects in multiple natural environments
Winter Survival of Grasses and Legumes in Subarctic Alaska as Related to Latitudinal Adaptation, Pre-Winter Storage of Food Reserves, and Dry-Matter Concentration in Overwintering Tissues
similar experiments, were to (a) compare winter
hardiness in subarctic Alaska of numerous plant species
and ecotypes from various latitudinal sources
within most species, and (b) seek a better understanding
of certain aspects of pre-winter physiologic changes
in plants that are associated with successful or with
unsuccessful winter survival in this northern area.
Both experiments were conducted at the University of
Alaska’s Matanuska Research Farm (61.6°N) near
Palmer in southcentral Alaska
Characterization of Cynara cardunculus L. flower from Alentejo as a coagulant agent for cheesemaking
The cardoon (Cynara cardunculus L.) is a mandatory vegetable coagulant for certain Protected Designation
of Origin Portuguese cheeses. It grows wild in Portugal and is used without any type of control regarding
flower picking or extract preparation, representing some uncertainty in cheese manufacture. The variability in technological properties, in the context of traditional cheese manufacture, of cardoon flower
ecotypes from the Alentejo region was evaluated, including milk clotting and proteolytic activities,
coagulation properties and potential cheesemaking yield of flower extracts. Multivariate statistics
highlighted the variability of flower properties for cheesemaking, but allowed the aggregation of the
ecotypes into five groups under the major influence of milk clotting activity and effect on gel firmness
and micellar aggregation rate, followed by proteolytic activity. These differences may have an impact on
cheese properties and therefore can allow the selection of cardoon flower for the manufacture of
different types of cheese
Draft genome sequences of five new strains of methylophilaceae isolated from lake washington sediment.
We sequenced the genomes of five new Methylophilaceae strains isolated from Lake Washington sediment. We used the new sequences to sort these new strains into specific Methylophilaceae ecotypes, including one novel ecotype. The new genomes expand the known diversity of Methylophilaceae and provide new models for studying the ecology of methylotrophy
Exploring the utility of Brachypodium distachyon as a model pathosystem for the wheat pathogen Zymoseptoria tritici
peer-reviewedBackground
Zymoseptoria tritici, the causative organism of Septoria tritici blotch disease is a prevalent biotic stressor of wheat production, exerting substantial economic constraints on farmers, requiring intensive chemical control to protect yields. A hemibiotrophic pathogen with a long asymptomless phase of up to 11 days post inoculation (dpi) before a rapid switch to necrotrophy; a deficit exists in our understanding of the events occurring within the host during the two phases of infection. Brachypodium distachyon has demonstrated its potential as a model species for the investigation of fungal disease resistance in cereal and grass species. The aim of this study was to assess the physical interaction between Z. tritici (strain IPO323) and B. distachyon and examine its potential as a model pathosystem for Z. tritici.
Results
Septoria tritici blotch symptoms developed on the wheat cultivar Riband from 12 dpi with pycnidial formation abundant by 20 dpi. Symptoms on B. distachyon ecotype Bd21-1 were visible from 1 dpi: characteristic pale, water soaked lesions which developed into blotch-like lesions by 4 dpi. These lesions then became necrotic with chlorotic regions expanding up to 7 dpi. Sporulation on B. distachyon tissues was not observed and no evidence of fungal penetration could be obtained, indicating that Z. tritici was unable to complete its life cycle within B. distachyon ecotypes. However, observation of host responses to the Z. tritici strain IPO323 in five B. distachyon ecotypes revealed a variation in resistance responses, ranging from immunity to a chlorotic/necrotic phenotype.
Conclusions
The observed interactions suggest that B. distachyon is an incompatible host for Z. tritici infection, with STB symptom development on B. distachyon comparable to that observed during the early infection stages on the natural host, wheat. However first visible symptoms occurred more rapidly on B. distachyon; from 1 dpi in comparison to 12 dpi in wheat. Consequently, we propose that the interaction between B. distachyon and Z. tritici as observed in this study could serve as a suitable model pathosystem with which to investigate mechanisms underpinning an incompatible host response to Z. tritici.Teagasc Walsh Fellowship Programm
- …
