Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Accueil du site → Doctorat → Argentine → Diversidad de las comunidades microbianas de los suelos pampeanos. Enfoques ecológicos y metagenómicos

Universidad de Buenos Aires (2014)

Diversidad de las comunidades microbianas de los suelos pampeanos. Enfoques ecológicos y metagenómicos

Carbonetto, María Belén

Titre : Diversidad de las comunidades microbianas de los suelos pampeanos. Enfoques ecológicos y metagenómicos

Diversity of soil microbial communities of the Pampas. Ecological and metagenomic approaches

Auteur : Carbonetto, María Belén

Université de soutenance : Universidad de Buenos Aires

Grade : Doctor Ciencias Biológicas 2014

Résumé
Soil is one of the most biodiverse and heterogeneous environments of Earth. Soil bio-chemical processes are essential for life and are carried out by microorganisms, mainly Bacteria and Archaea. Moreover soil is very important for humans, since it is the main source of food ; but as any other natural resource it is not limitless. Though studying the impact of agriculture on soil physical, chemical and biological characteristics, and hence on ecosystem processes is imperative. The 50% of Pampas surface is devoted to agriculture. The impact of agricultural practices on soil physical and chemical properties has been extensively studied in the region. However, beyond the great effort made, there is a debt yet to understand the consequences of agriculture on biodiversity and biological processes. The work presented here aims to repay part of this debt by studying the impact of agriculture on soil bacterial communities of the Pampas. We used an ecological approach and 50% of the surface of Pampas is devoted to agriculture. The impact of agricultural practices on soil physical and chemical characteristics has been extensively studied in the region. However, beyond the great effort made, there is a debt yet to understand the consequences of agricultural biodiversity and biological processes. The work presented here aims to repay this debt of studying the impact that agriculture on soil bacterial communities of the Pampas. We used an ecological approach and metagenomics. The first chapter was focused on the study of the impact of over 100 years of farming on the structure of microbial communities and their metabolic (metagenomic) profiles. Significant differences between communities of soils with and without a history of agricultural management were found. The second chapter is devoted to the comparison of two tillage systems. We studied the structure and metagenomic profiles of soil communities under conventional tillage and no-tillage. We found that communities differ in their taxonomical composition and metabolisms. The aim of the third chapter was to determine the regional pattern of bacterial distribution. This analysis was performed within the framework of the theory of metacommunities. We sampled soils with and without soil management history, in an East-West transect that spanned the entire climatic and edaphic gradient of the Pampas. The results showed that dispersion was more important than environmental contemporaneous effects at the regional level, thus masking local impacts generated by agricultural use.

Mots clés : ECOLOGIA MICROBIANA ; MICROBIOLOGIA DE SUELOS ; REGION PAMPEANA ; METAGENOMICA ; AGRICULTURA ; MICROBIAL ECOLOGY ; SOIL MICROBIOLOGY ; ARGENTINE PAMPAS ; METAGENOMICS ; AGRICULTURE

Présentation

Version intégrale

Page publiée le 24 janvier 2015, mise à jour le 3 juillet 2017