Search results for "communauté"
showing 10 items of 137 documents
Infestation de Rhamphicarpa fistulosa (Hoschst.) Benth. en riziculture de bas-fonds au nord du Togo
2016
International audience; Le riz constitue de nos jours la base alimentaire de plus de 2,5 milliards de personnes en Afrique subsaharienne où sa demande ne cesse de croître. Pour faire face à cette demande qui dépasse souvent doublement les productions nationales, et pour diminuer ses importations sans cesse croissantes, le Togo à l’instar des pays ouest-Africains a élaboré un document stratégique qui mise sur l’extension et la productivité des rizières de bas-fond. Malheureusement, les bas-fonds rizicoles en Afrique tropicale sont souvent confrontés à la pression des adventices et plus particulièrement des adventices parasites de la famille des Orobanchaceae. Rhamphicarpa fistulosa, plante h…
Search for biological signature of the degradation of chlordecone in soil of the French West Indies
2015
The use of chlordecone (CLD) to eradicate the weevil populations in the banana plantations in the French West Indies (Guadeloupe and Martinique) between 1972 and 1993 led to the contamination of the soil and the environment. This very hydrophobic organochlorine insecticide persists in the soil where it slowly transfers not only to the water resources but also to terrestrial and aquatic biota (plants, animals, fishes, shellfishes). Deemed “non-degradable”, CLD is resistant to photolysis, hydrolysis and biodegradation. To date, there is no method to remediate the 20,000 hectares of polluted soil with this insecticide. Given the extent of CLD pollution, biological decontamination processes app…
Response of soil bacterial communities to the incorporation of crop residues : influence of agricultural practices and link with the soil biological …
2010
The effect of the location of wheat residues (soil surface vs. incorporated in soil) on their decomposition and on soil bacterial communities was investigated by the means of a field experiment. Bacterial-Automated Ribosomal Intergenic Spacer Analysis (B-ARISA) of DNA extracts from residues, detritusphere (soil adjacent to residues), and bulk soil evidenced that residues constitute the zone of maximal changes in bacterial composition. However, the location of the residues influenced greatly their decomposition and the dynamics of the colonizing bacterial communities. Sequencing of 16S rRNA gene in DNA extracts from the residues at the early, middle, and late stages of degradation confirmed …
DIAGSOL : development of a new functional marker of exposure to herbicides B-triketones in an agricultural soil
2020
Numerous herbicides target an enzyme found not only in weeds but also in « non-target organisms » such as microorganisms. This proof-of-concept study aims to use microbial gene encoding the targeted enzyme or the targeted enzyme itself as a marker for herbicide exposure in soils. The hppd gene and the encoded enzyme (HPPD; 4-hydroxyphenylpyruvate dioxygenase), targeted by B-triketone herbicides, are the subject of this study. In silico analyses reveal that the hppd gene is spread out in all bacterial phyla. Primers specific to this gene were designed. This primer pair is used to measure the abundance, the composition and the diversity of the hppd bacterial community in soil microcosms expos…
Response of soil bacterial communities to the incorporation of crop residues : influence of agricultural practices and link with the soil biological …
2010
The effect of the location of wheat residues (soil surface vs. incorporated in soil) on their decomposition and on soil bacterial communities was investigated by the means of a field experiment. Bacterial-Automated Ribosomal Intergenic Spacer Analysis (B-ARISA) of DNA extracts from residues, detritusphere (soil adjacent to residues), and bulk soil evidenced that residues constitute the zone of maximal changes in bacterial composition. However, the location of the residues influenced greatly their decomposition and the dynamics of the colonizing bacterial communities. Sequencing of 16S rRNA gene in DNA extracts from the residues at the early, middle, and late stages of degradation confirmed …
Metaproteomics: a new approach for studying functional microbial ecology
2008
Establishing the link between microbial diversity and ecosystem functioning constitutes one of the fundamental questions in microbial ecology. However, microbial biodiversity cannot be resolved in a single manner and the question arises about which of the genetic and/or taxonomic and/or functional components of biodiversity are the most relevant in such a problematic. To date, most researches in this field has focused on genetic diversity and few investigations have examined functional diversity, resulting in a poor understanding of the manner in which genetic and taxonomic diversity affect functional diversity or ecosystem properties. This can be explained by paucity of methods allowing an…
Distribution et déterminisme de la diversité des communautés de champignons telluriques à l'échelle de trois régions françaises
2009
aeres : C-ACTN; National audience; no abstract
Distribution and determinism of abundance, diversity and structure of microbial communities at different spatial scales to support agricultural devel…
2018
Les propriétés des sols déterminent notre capacité à produire des biens et des services en quantité et en qualité. Dans ce contexte, la composante microbienne des sols occupe une place prépondérante de part son abondance et son extrême diversité : on estime qu’un gramme de sol contient 109 bactéries et 105 champignons, pour environ 106 espèces bactériennes et 103 à 104 espèces de champignons. Cette diversité taxonomique des microorganismes du sol supporte une extraordinaire diversité fonctionnelle qui leur confère un rôle déterminant dans le fonctionnement du sol tant qualitativement (cycles biogéochimiques, structure du sol ; dégradation des composés exogènes, régulation biologique) que qu…
Lien entre la diversité microbienne, la stabilité des communautés microbiennes et le turnover des matières organiques du sol
2014
Soil microbial communities act as important agents of the biological soil functioning, particularly through their involvements in the transformations of biogeochemical cycles (C, N, P…). In agro-ecosystems, the diversity of these communities is affected by perturbations associated to agricultural practices, and the significance of these modifications in terms of preservation of biological functioning and sustainability of agricultural systems has emerged as a central issue in the environmental sciences. Whereas the role of biodiversity has been well studied for macroorganisms, in particular for plants; the biodiversity/activity relationship is still largely unknown for soil microorganisms. …
Apport des nouvelles générations de séquençage pour accéder à la diversité des communautés microbiennes du sol : nécessité d’un ‘pipeline’ bio-inform…
2012
National audience