Search results for "Symbiosi"

Proteomes of arbuscular mycorrhizal symbiosis : past and present achievements

2008

High-troughput TILLING to identify symbiosis-related plant gene function in arbuscular mycorrhiza

2006

International audience

Legumes in 21st century Europe: present and future importance in agri-food systems? New challenges for reseach.

2013

Intensification of agriculture since 1950 has globally led to the decline of grain legume crops, which currently represent less than 3 % of arable crops in France and Europe. Nevertheless, legumes have several major assets (i) as plant proteins for animal feed and human food and (ii) as plants fixing atmospheric N2 and thereby saving nitrogen inputs in cropping systems, and (iii) as diversification crops. The analysis of forage and grain legume producing systems in France showed that the dominant system results in a lock-in of the different factors limiting legume insertion into the current systems. But legumes could have a major role to play in the agroecological transition towards more su…

Managing biotic interactions for ecological intensification of agroecosystems.

2014

9 pages; International audience; Agriculture faces the challenge of increasing food production while simultaneously reducing the use of inputs and delivering other ecosystem services. Ecological intensification of agriculture is a paradigm shift, which has recently been proposed to meet such challenges through the manipulation of biotic interactions. While this approach opens up new possibilities, there are many constraints related to the complexity of agroecosystems that make it difficult to implement. Future advances, which are essential to guide agricultural policy, require an eco-evolutionary framework to ensure that ecological intensification is beneficial in the long term.

Okadaic Acid, an Apoptogenic Toxin for Symbiotic/Parasitic Annelids in the Demosponge Suberites domuncula

2006

ABSTRACT The role of okadaic acid (OA) in the defense system of the marine demosponge Suberites domuncula against symbiotic/parasitic annelids was examined. Bacteria within the mesohyl produced okadaic acid at concentrations between 32 ng/g and 58 ng/g of tissue (wet weight). By immunocytochemical methods and by use of antibodies against OA, we showed that the toxin was intracellularly stored in vesicles. Western blotting experiments demonstrated that OA also existed bound to a protein with a molecular weight of 35,000 which was tentatively identified as a galectin (by application of antigalectin antibodies). Annelids that are found in S. domuncula undergo apoptotic cell death. OA is one ca…

Blue-green algalike cells associated with the tunic of Ciona intestinalis L.

1980

Certain organisms resembling blue-green algae embedded in the tunic of the solitary ascidian Ciona intestinalis L. are described. Their probable symbiotic role as related to the peculiar habitat of this ascidian is suggested.

Tempo and mode of early gene loss in endosymbiotic bacteria from insects

2006

Abstract Background Understanding evolutionary processes that drive genome reduction requires determining the tempo (rate) and the mode (size and types of deletions) of gene losses. In this study, we analysed five endosymbiotic genome sequences of the gamma-proteobacteria (three different Buchnera aphidicola strains, Wigglesworthia glossinidia, Blochmannia floridanus) to test if gene loss could be driven by the selective importance of genes. We used a parsimony method to reconstruct a minimal ancestral genome of insect endosymbionts and quantified gene loss along the branches of the phylogenetic tree. To evaluate the selective or functional importance of genes, we used a parameter that meas…

Shaping the antipredator strategy: flexibility, consistency, and behavioral correlations under varying predation threat

2014

9 pages; International audience; Recent ecological and evolutionary research emphasizes the importance of adaptive trait integration. For instance, antipredator defenses are built up of several morphological and behavioral components in many species, yet their functional relationships are still poorly documented. Using field-collected freshwater crustaceans Gammarus fossarum in a within-subject design, we investigated the flexibility and consistency of refuge use, photophobia, and exploration behavior as well as their associations, quantified both when predation risk was absent or artificially simulated. In agreement with the "threat-sensitivity" hypothesis, both refuge use and photophobia …

Mycorrhizal benefit differs among the sexes in a gynodioecious species

2010

Both plant sex and arbuscular mycorrhizal (AM) symbiosis influence resource acquisition and allocation in plants, but the interaction between these two components is not well established. As the different plant sexes differ in their resource needs and allocation patterns, it is logical to presume that they might differ in their relationship with AM as well. We investigate whether the association with AM symbiosis is different according to the host plant sex in the gynodioecious Geranium sylvaticum, of which, besides female and hermaphrodite plants, intermediate plants are also recognized. Specifically, we examine the effects of two different AM fungi in plant mass allocation and phosphorus …

The effect of host mycorrhizal status on host plant-parasitic plant interactions

2001

Two pot experiments were conducted to examine three-level interactions between host plants, mycorrhizal fungi and parasitic plants. In a greenhouse experiment, Poa annua plants were grown in the presence or absence of an AM fungus (either Glomus lamellosum V43a or G. mosseae BEG29) and in the presence or absence of a root hemiparasitic plant (Odontites vulgaris). In a laboratory experiment, mycorrhizal infection (Glomus claroideum BEG31) of Trifolium pratense host plants (mycorrhizal versus non-mycorrhizal) was combined with hemiparasite infection (Rhinanthus serotinus) of the host (parasitized versus non-parasitized). Infection with the two species of Glomus had no significant effect on th…