Search results for "COMMUNITIES"

Microalgae community structure analysis based on 18S rDNA amplification from DNA extracted directly from soil as a potential soil bioindicator

2005

International audience; Soil algae are photosynthetically active microorganisms showing changeable community structure, depending on the soil type, the agricultural practices and the application of pesticides. To characterise algal community structure, molecular approaches complementary to classical microbiological approaches based on the isolation and the culture of soil algae are required. Our study describes a polymerase chain reaction (PCR) approach targeting algal 18S rDNA sequences of desoxyribonucleic acid (DNA) samples extracted either from unialgal eukaryotic microalgae culture, complex assemblages of microalgae populations or natural soil communities. Our first results showed that…

Biogeography of soil microbial communities: a review and a description of the ongoing french national initiative

2010

International audience; Microbial biogeography is the study of the distribution of microbial diversity on large scales of space and time. This science aims at understanding biodiversity regulation and its link with ecosystem biological functioning, goods and services such as maintenance of productivity, of soil and atmospheric quality, and of soil health. Although the initial concept dates from the early 20th century (Beijerinck (1913) De infusies en de ontdekking der backterien, in: Jaarboek van de Knoniklijke Akademie van Wetenschappen, Muller, Amsterdam), only recently have an increasing number of studies have investigated the biogeographical patterns of soil microbial diversity. A such …

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…

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…

Plant genotype: a lever in the interactions between plant and its associated rhizosphere microbiome

2018

International audience; In the context of highly pressured agricultural production using low levels of inputs, cropping strategies could take advantage of existing plant-microbiome interactions that can improve both plant growth and health. We believe that plant genetics can provide some clues to better understand the mechanisms underlying microbiome recruitment by the plant.The aims of this work were (i) to assess plant genotype effect on the rhizosphere bacterial communities in relation to the plant nutritional strategies for a core collection of 155 genotypes of Medicago truncatula and (ii) to highlight the genetic determinisms potentially associated in these interactions. To achieve the…

Multiple-scale distribution and function of soil microorganisms

2011

Evolution of genetic degradation potential of pesticide-degrading bacterial communities

2009

International audience

Translation of metagenomics agroecosystems in ecological services

2011

National audience

Spatial distribution of ammonia oxidizing bacteria and archaea across a 44-hectare farm related to ecosystem functioning

2011

Use of functional traits to study microbial diversity

2012

Microbial communities have a central role in many ecosystem functions such as biogeochemical cycling, filtering and climate regulation. However, while functional trait-based approaches are commonly used for at least two decades in microbiology, most microbial ecology studies are still carried out with the rRNA genes. This talk will highlight the advantages of trait-based approaches for studying microbial diversity and its relationship with ecosystem functions. For this purpose, denitrification, a microbial process involved in N-cycling, was selected as a model functional trait. Using both naturally assembled and artificially manipulated communities, we will show how the diversity of the den…