Vidal, Stefan

[["dc.bibliographiccitation.firstpage","1358"],["dc.bibliographiccitation.issue","5"],["dc.bibliographiccitation.journal","Environmental Entomology"],["dc.bibliographiccitation.lastpage","1366"],["dc.bibliographiccitation.volume","44"],["dc.contributor.author","Alkhedir, Hussein"],["dc.contributor.author","Karlovsky, Petr"],["dc.contributor.author","Mashaly, Ashraf Mohamed Ali"],["dc.contributor.author","Vidal, Stefan"],["dc.date.accessioned","2018-11-07T09:50:53Z"],["dc.date.available","2018-11-07T09:50:53Z"],["dc.date.issued","2015"],["dc.description.abstract","Aphids have developed symbiotic associations with different bacterial species, and some morphological and molecular analyses have provided evidence of the host relationship between the primary symbiotic bacteria (Buchnera aphidicola) and the aphid while the contrary with the secondary symbiotic bacteria. In this study, we investigated the phylogenetic relationships of the bacterial endosymbionts in the aphid Sitobion avenae (F.). We characterized all bacterial endosymbionts in 10 genetically defined S. avenae clones by denaturing gradient gel electrophoresis and, from these clones, sequenced the 16S rRNA genes of both the primary endosymbiont, B. aphidicola (for the first time), and the secondary endosymbionts, Regiella insecticola and Hamiltonella defensa (for the first time). The phylogenetic analysis indicated that Buchnera from Sitobion related to those in Macrosiphoni. The analysis of the secondary endosymbionts indicated that there is no host relationship between H. defensa and R. insecticola from Sitobion and those from other aphid species. In this study, therefore, we identified further evidence for the relationship between Buchnera and its host and reported a relationship within the secondary endosymbionts of S. avenae from the same country, even though there were no relationships between the secondary bacteria and their host. We also discussed the diversity within the symbiotic bacteria in S. avenae clones."],["dc.description.sponsorship","Deanship of Scientific Research at King Saud University [RGPVPP-028]"],["dc.identifier.doi","10.1093/ee/nvv114"],["dc.identifier.isi","000362820900008"],["dc.identifier.pmid","26314016"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/35800"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Oxford Univ Press Inc"],["dc.relation.issn","1938-2936"],["dc.relation.issn","0046-225X"],["dc.title","Phylogenetic Relationships of the Symbiotic Bacteria in the Aphid Sitobion avenae (Hemiptera: Aphididae)"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","100"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Plant Pathology"],["dc.bibliographiccitation.lastpage","111"],["dc.bibliographiccitation.volume","59"],["dc.contributor.author","Jaeschke, D."],["dc.contributor.author","Dugassa-Gobena, Dereje"],["dc.contributor.author","Karlovsky, Petr"],["dc.contributor.author","Vidal, Stefan"],["dc.contributor.author","Ludwig-Mueller, Jutta"],["dc.date.accessioned","2018-11-07T08:46:34Z"],["dc.date.available","2018-11-07T08:46:34Z"],["dc.date.issued","2010"],["dc.description.abstract","This study investigated the ability of an endophytic fungus Acremonium alternatum to reduce clubroot formation in the model plant Arabidopsis thaliana, which is highly susceptible to Plasmodiophora brassicae. Quantitative PCR demonstrated that A. alternatum colonized the P. brassicae-infected roots and shoots of the host plant. When Arabidopsis plants were co-inoculated with P. brassicae and A. alternatum, gall formation was reduced as shown by the reduction of the disease index (DI) by up to 50% compared to plants only infected with P. brassicae, whereas the infection rate was lowered by about 20% only in several, but not all, experiments. Clubroot was similarly suppressed when plants were inoculated with autoclaved A. alternatum spores or spore extracts, showing that viable spores were not needed. However, A. alternatum spores did not inhibit P. brassicae resting spore germination. Compared to the normal root galls, the smaller root galls on A. alternatum-inoculated plants contained fewer resting spores of the clubroot pathogen. It was thus hypothesized that inoculation with A. alternatum delayed the development of P. brassicae. Using quantitative RT-PCR to monitor the expression of P. brassicae genes differentially expressed during the development of the disease, a delayed pathogen development was corroborated. Furthermore, greenhouse experiments identified a time window in which the endophyte had to be administered, where the latest effective time point was 5 days before inoculation with P. brassicae and the optimum treatment was to administer A. alternatum and P. brassicae at the same time. These results indicate that A. alternatum and perhaps similar endophytes could be useful for the management of clubroot disease."],["dc.identifier.doi","10.1111/j.1365-3059.2009.02199.x"],["dc.identifier.isi","000273477800012"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/20728"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-blackwell Publishing, Inc"],["dc.relation.issn","0032-0862"],["dc.title","Suppression of clubroot (Plasmodiophora brassicae) development in Arabidopsis thaliana by the endophytic fungus Acremonium alternatum"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1999"],["dc.bibliographiccitation.issue","12"],["dc.bibliographiccitation.journal","Journal of Insect Physiology"],["dc.bibliographiccitation.lastpage","2005"],["dc.bibliographiccitation.volume","56"],["dc.contributor.author","Alkhedir, Hussein"],["dc.contributor.author","Karlovsky, Petr"],["dc.contributor.author","Vidal, Stefan"],["dc.date.accessioned","2018-11-07T08:36:22Z"],["dc.date.available","2018-11-07T08:36:22Z"],["dc.date.issued","2010"],["dc.description.abstract","The grain aphid Sitobion avenae F one of the major pest aphids of cereals in Central Europe exhibits colour polymorphism even within the same clones Although there is evidence that green and brown morphs of S avenae contain different carotenoids the mechanisms determining the induction of colour morphs are unknown The common understanding is that the formation of colour morphs is controlled by light and affected by genetic and environmental factors and by host plant species So far there is no unequivocal evidence that light intensity photoperiod or a mixture of several variables are Involved in the induction of S avenae colour formation resulting in the induction of S avenae colour formation and carotenoid synthesis Here we determined the effect of light intensity on the colour formation and performance of ten clones of S avenae with experiments that controlled for the effects of host plant and genetic factors We found that some clones remained green under all test conditions In other clones colour morph formation was controlled by light The synthesis of carotenoids correlated with changes in colour formation Host plant did not affect colour formation in the ten clones studied Although colour of the aphid clones did not affect their performance high light intensity increased the fecundity and fresh weight of S avenae clones while low light intensity stimulated the production of alatae (C) 2010 Elsevier Ltd All rights reserved"],["dc.identifier.doi","10.1016/j.jinsphys.2010.08.025"],["dc.identifier.isi","000284568800037"],["dc.identifier.pmid","20826158"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/18294"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Pergamon-elsevier Science Ltd"],["dc.relation.issn","0022-1910"],["dc.title","Effect of light intensity on colour morph formation and performance of the grain aphid Sitobion avenae F (Homoptera Aphididae)"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","289"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Applied Entomology and Zoology"],["dc.bibliographiccitation.lastpage","295"],["dc.bibliographiccitation.volume","51"],["dc.contributor.author","Alkhedir, Hussein"],["dc.contributor.author","Karlovsky, Petr"],["dc.contributor.author","Mashaly, Ashraf Mohemed Ali"],["dc.contributor.author","Vidal, Stefan"],["dc.date.accessioned","2018-11-07T10:14:55Z"],["dc.date.available","2018-11-07T10:14:55Z"],["dc.date.issued","2016"],["dc.description.abstract","The performance of 10 clones of the grain aphid Sitobion avenae Fabricius was measured over three generations on three host plants (wheat, bluegrass and ryegrass). The tested clones belonged to six microsatellite genotypes; two genotypes were represented by three clonal lines each that had been collected from different host plants. The clones varied in body color and in the secondary endosymbionts they possessed (Hamiltonella, Regiella or none). The performance of aphids on host plants declined in the order wheat > bluegrass > ryegrass independently of the plant from which they were collected. We also found differences in performance among genotypes and clones of the aphids and among the generations at which the performance was measured. The performance was not affected by the collection site, clone's original host plant, body color or the presence of endosymbionts."],["dc.description.sponsorship","Deanship of Scientific Research at King Saud University [RGPVPP-028]"],["dc.identifier.doi","10.1007/s13355-016-0400-0"],["dc.identifier.isi","000374579300013"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/40717"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Springer"],["dc.relation.issn","1347-605X"],["dc.relation.issn","0003-6862"],["dc.title","Specialization and host plant use of the common clones of Sitobion avenae (Homoptera: Aphididae)"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1532"],["dc.bibliographiccitation.issue","5"],["dc.bibliographiccitation.journal","Environmental Entomology"],["dc.bibliographiccitation.lastpage","1538"],["dc.bibliographiccitation.volume","39"],["dc.contributor.author","Kurtz, Benedikt"],["dc.contributor.author","Karlovsky, Petr"],["dc.contributor.author","Vidal, Stefan"],["dc.date.accessioned","2018-11-07T08:38:23Z"],["dc.date.available","2018-11-07T08:38:23Z"],["dc.date.issued","2010"],["dc.description.abstract","A greenhouse experiment was conducted to evaluate the effect of soil-dwelling larvae of the western corn rootworm, Diabrotica virgifera virgifera LeConte, on infection of maize roots by the mycotoxin-producing plant-pathogenic fungus, Fusarium verticillioides (Saccardo) Nirenberg (synonym = Fusarium moniliforme Sheldon). The time and order of application of F. verticillioides and western corn rootworm were varied in three different treatments to investigate the influence of timing on root colonization of F. verticillioides and western corn rootworm larval development. Root feeding by western corn rootworm larvae increased root colonization by F. verticillioides (as determined by real-time polymerase chain reaction) up to 50-fold when a high inoculum (10(7) spores/plant) of F. verticillioides was applied before western corn rootworm eggs were added. This effect was stronger the earlier F. verticillioides was applied relative to the time of western corn rootworm egg application but was only significant for the high F. verticillioides inoculum density treatment; F. verticillioides colonization was not increased when a low F. verticillioides inoculum density (106 spores/plant) was applied. F. verticillioides slightly suppressed larval development in that the ratio of second- to third-instar larvae was higher in treatments with F. verticillioides than without F. verticillioides. F. verticillioides reduced western corn rootworm head capsule width when applied before or simultaneously with western corn rootworm. The results of this study are discussed focusing on conditions that favor root colonization by F. verticillioides and its influence on western corn rootworm larval development."],["dc.description.sponsorship","DFG (German Research Foundation)"],["dc.identifier.doi","10.1603/EN10025"],["dc.identifier.isi","000282852600017"],["dc.identifier.pmid","22546449"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/18755"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Entomological Soc Amer"],["dc.relation.issn","0046-225X"],["dc.title","Interaction Between Western Corn Rootworm (Coleoptera: Chrysomelidae) Larvae and Root-Infecting Fusarium verticillioides"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","40914"],["dc.bibliographiccitation.journal","Scientific Reports"],["dc.bibliographiccitation.volume","7"],["dc.contributor.author","Wemheuer, Franziska"],["dc.contributor.author","Kaiser, Kristin"],["dc.contributor.author","Karlovsky, Petr"],["dc.contributor.author","Daniel, Rolf"],["dc.contributor.author","Vidal, Stefan"],["dc.contributor.author","Wemheuer, Bernd"],["dc.date.accessioned","2018-11-07T10:28:18Z"],["dc.date.available","2018-11-07T10:28:18Z"],["dc.date.issued","2017"],["dc.description.abstract","Endophytic bacteria are critical for plant growth and health. However, compositional and functional responses of bacterial endophyte communities towards agricultural practices are still poorly understood. Hence, we analyzed the influence of fertilizer application and mowing frequency on bacterial endophytes in three agriculturally important grass species. For this purpose, we examined bacterial endophytic communities in aerial plant parts of Dactylis glomerata L., Festuca rubra L., and Lolium perenne L. by pyrotag sequencing of bacterial 16S rRNA genes over two consecutive years. Although management regimes influenced endophyte communities, observed responses were grass species-specific. This might be attributed to several bacteria specifically associated with a single grass species. We further predicted functional profiles from obtained 16S rRNA data. These profiles revealed that predicted abundances of genes involved in plant growth promotion or nitrogen metabolism differed between grass species and between management regimes. Moreover, structural and functional community patterns showed no correlation to each other indicating that plant species-specific selection of endophytes is driven by functional rather than phylogenetic traits. The unique combination of 16S rRNA data and functional profiles provided a holistic picture of compositional and functional responses of bacterial endophytes in agricultural relevant grass species towards management practices."],["dc.description.sponsorship","Open-Access-Publikationsfonds 2017"],["dc.identifier.doi","10.1038/srep40914"],["dc.identifier.isi","000392296200001"],["dc.identifier.pmid","28102323"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/14262"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/43397"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","PUB_WoS_Import"],["dc.relation.issn","2045-2322"],["dc.rights.access","openAccess"],["dc.title","Bacterial endophyte communities of three agricultural important grass species differ in their response towards management regimes"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","e54327"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","PLoS ONE"],["dc.bibliographiccitation.volume","8"],["dc.contributor.author","Alkhedir, Hussein"],["dc.contributor.author","Karlovsky, Petr"],["dc.contributor.author","Vidal, Stefan"],["dc.date.accessioned","2018-11-07T09:29:12Z"],["dc.date.available","2018-11-07T09:29:12Z"],["dc.date.issued","2013"],["dc.description.abstract","Aphids feed on plant phloem sap, rich in sugars but poor in essential amino acids. However, sugars cause osmotic regulation problems for aphids, which they overcome by hydrolysing the sugars in their gut and polymerising the hydrolysis products into oligosaccharides, excreted with honeydew. Aphids harbour primary bacterial endosymbionts, which supply them with essential amino acids necessary for survival. They also harbour secondary (facultative) endosymbionts (sfS), some of which have a positive impact on life history traits, although it is not yet known whether they also play a role in providing effective tolerance to differing levels of water soluble carbohydrates (WSCs). We investigated the relationship between WSC content of cocksfoot cultivars and performance of clones of the English grain aphid Sitobion avenae F. We evaluated how clone genotype and their sfS modulate performance on these different cultivars. We therefore examined the performance of genetically defined clones of S. avenae, collected from different host plants, harbouring different sfS. The performance was tested on 10 Dactylis glomerata L. cultivars with varying WSC content. D. glomerata is known as a wild host plant for S. avenae and is also commercially planted. We found that high WSCs levels are responsible for the resistance of D. glomerata cultivars to specific S. avenae clones. The minimum level of WSCs conferring resistance to D. glomerata cultivars was 1.7% dw. Cultivars with a WSC content of 2.2% or higher were resistant to S. avenae and did not allow reproduction. Our results further indicate that sfS modulate to some extend host plant cultivar adaptation in S. avenae. This is the first study revealing the importance of WSCs for aphid performance. Cocksfoot cultivars with a high content of WSCs might be therefore considered for aphid control or used for resistance breeding in this and other grass species, including cereals."],["dc.description.sponsorship","Open-Access-Publikationsfonds 2013"],["dc.identifier.doi","10.1371/journal.pone.0054327"],["dc.identifier.isi","000314759400149"],["dc.identifier.pmid","23342134"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/8519"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/30963"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Public Library Science"],["dc.relation.issn","1932-6203"],["dc.rights","CC BY 3.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/3.0/"],["dc.title","Relationship between Water Soluble Carbohydrate Content, Aphid Endosymbionts and Clonal Performance of Sitobion avenae on Cocksfoot Cultivars"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]