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Université de Neuchâtel

Synergies and trade-offs between insect and pathogen resistance in maize leaves and roots

Erb, Matthias ; Balmer, Yves ; de Lange, Elvira S. ; von Merey, Georg ; Planchamp, Chantal ; Robert, Christelle Aurélie Maud ; Röder, Gregory ; Sobhy, Islam ; Zwahlen, Claudia ; Mauch-Mani, Brigitte ; Turlings, Ted C. J.

In: Plant, Cell & Environment, 2011, vol. 34, no. 7, p. 1088-1103

Determining links between plant defence strategies is important to understand plant evolution and to optimize crop breeding strategies. Although several examples of synergies and trade-offs between defence traits are known for plants that are under attack by multiple organisms, few studies have attempted to measure correlations of defensive strategies using specific single attackers. Such links...

Université de Neuchâtel

Produire du lait, créer du sens : adaptations et résistances quotidiennes chez les producteurs de lait suisses romands

Forney, Jérémie ; Ghasarian, Christian (Dir.) ; Droz, Yvan (Codir.)

Thèse de doctorat : Université de Neuchâtel, 2010.

Produire du lait en Suisse romande, c’est exercer une activité économique conditionnée par un cadre politique omniprésent. Au tournant du siècle, ce cadre a subi une transformation profonde. D’un système protectionniste et productiviste, on est passé à une logique libérale, associée à une rhétorique de multifonctionnalité. Les éleveurs laitiers ont dû trouver les moyens de...

Université de Neuchâtel

Facteurs de résistance à l'oïdium (Erysiphe necator Schwein.) chez la vigne (Vitis vinifera L.)

Schnee, Sylvain ; Viret, Olivier (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2008 ; Th.2062.

Powdery mildew is one of the most important fungal diseases of cultivated grapevine (Vitis vinifera). The causal agent, Erysiphe necator, is an obligate biotrophic pathogen epiphyte producing specialized infectious structures in the host epidermal cells to take up nutrients. The occurrence of resistant species within the genus Vitis allows studying the role played by...

EPFL

The influence of cattle activity on tree regeneration in wood-pastures

Vandenberghe, Charlotte ; Buttler, Alexandre (Dir.)

Thèse sciences Ecole polytechnique fédérale de Lausanne EPFL : 2006 ; no 3649.

Université de Fribourg

Experimental evolution of field populations of Daphnia magna in response to parasite treatment

Zbinden, Marc ; Haag, Christoph R. ; Ebert, Dieter

In: Journal of Evolutionary Biology, 2008///doi:10.1111/j.1420-9101.2008.01541.x

Although there is little doubt that hosts evolve to reduce parasite damage, little is known about the evolutionary time scale on which host populations may adapt under natural conditions. Here we study the effects of selection by the microsporidian parasite Octosporea bayeri on populations of Daphnia magna. In a field study, we infected replicated populations of D. magna with the parasite,...

Université de Fribourg

Testing the Evolution of Increased Competitive Ability (EICA) hypothesis in a novel framework

Handley, Richard J. ; Steinger, Thomas ; Treier, Urs A. ; Müller-Schärer, Heinz

In: Ecology, 2008, vol. 89, no. 2, p. 407–417

The “evolution of increased competitive ability” (EICA) hypothesis proposes that escape from natural enemies, e.g., after transcontinental introductions, alters the selection regime because costly defenses no longer enhance fitness. Such an evolutionary loss of defenses enables resources to be directed toward growth or other traits improving performance. We tested the EICA hypothesis in a...

Université de Neuchâtel

Characterization of an Arabidopsis–Phytophthora Pathosystem: resistance requires a functional PAD2 gene and is independent of salicylic acid, ethylene and jasmonic acid signalling

Roetschi, Alexandra ; Si-Ammour, Azeddine ; Belbahri, Lassaâd ; Mauch, Felix ; Mauch-Mani, Brigitte

In: The Plant Journal, 2001, vol. 28, no. 2, p. 293-305

Arabidopsis accessions were screened with isolates of Phytophthora porri originally isolated from other crucifer species. The described Arabidopsis–Phytophthora pathosystem shows the characteristics of a facultative biotrophic interaction similar to that seen in agronomically important diseases caused by Phytophthora species. In susceptible accessions, extensive...

Université de Fribourg

Parasite-mediated selection in experimental metapopulations of Daphnia magna

Haag, Christoph R. ; Ebert, Dieter

In: Proceedings of the Royal Society of London: Biological Sciences, 2004, vol. 271, p. 2149-2155

In metapopulations, only a fraction of all local host populations may be infected with a given parasite species, and limited dispersal of parasites suggests that colonization of host populations by parasites may involve only a small number of parasite strains. Using hosts and parasites obtained from a natural metapopulation, we studied the evolutionary consequences of invasion by single strains...

Université de Fribourg

Variation in phenoloxidase activity and its relation to parasite resistance within and between populations of Daphnia magna

Mucklow, Patrick T. ; Vizoso, Dita B. ; Jensen, Knut Helge ; Refardt, Dominik ; Ebert, Dieter

In: Proceedings of the Royal Society of London: Biological Sciences, 2004, vol. 271, p. 1175-1183

Estimates of phenoloxidase (PO) activity have been suggested as a useful indicator of immunocompetence in arthropods, with the idea that high PO activity would indicate high immunocompetence against parasites and pathogens. Here, we test for variation in PO activity among clones of the planktonic crustacean Daphnia magna and its covariation with susceptibility to infections from four different...