Laboratoire d’Ecologie Microbienne de Lyon (LEM)
(UMR CNRS 5557) (CNRS, INRA, Université Lyon 1)

The Research Unit UMR 5557 works on Microbial Ecology, a discipline at the crossroads of two major research fields: ecology and microbiology. This allows to bring together teachers and researchers from various institutions : CNRS (Centre National de la Recherche Scientifique), Université Claude Bernard Lyon 1, and INRA (Institut National de la Recherche Agronomique) VetAgro Sup (Campus vétérinaire de Lyon). And to belong, among others, to the Federative Research Institute Bio-Environment and Health (FR 41).

Microbial ecology aims to understand the physiology of microorganisms and the influence of their activities on other organisms and the environment in general, and, symmetrically, to clarify the impact of biotic and abiotic factors of the environment of these organisms, from the individual to the community in an ecosystem. Working on some key functions for the operation of the global ecosystem as denitrification or nitrogen fixation, we describe the microbial populations involved, their diversity and their fluctuations, the effects of these populations on the function in question and especially the role of these functions in the selective advantage.

LEM is composed of eight research groups. One team of the LEM is involved in the REGARDS project: Team 5, Microbial functional groups and nitrogen cycle. Our research focuses mainly on 2 microbial functional groups involved in nitrogen cycle (nitrifiers and denitrifiers). These organisms are responsible for complementary processes of the N cycle: Nitrifiers oxidizing ammonia into nitrate and denitrifiers reducing nitrate into gaseous N forms (NO, N2O, N2). Our activity is organised in 4 main axes: 1) the study of the mechanisms and environmental drivers that control the levels of the activity insured by model microorganisms or model microbial functional groups. Our studies account for the different possible microbial regulation levels, namely changes in the abundance, diversity and specific activity of these organisms. An important objective is to elucidate how the expression of functional genes coding key enzymes (nitrite reductase, nitrite oxido-reductase…) is modulated in the environment, and to understand the determinants of the spatial distribution of corresponding functions and organisms. 2) the relationship between diversity and functioning among nitrifiers and denitrifiers, taking into account the respective roles of taxonomic vs functional diversity; 3) the impact of plant biodiversity on the functioning and the diversity of nitrifiers and denitrifiers considering direct impact via the root exsudats and indirect impacts on environmental factors; 4) the impact of various factors of global changes (climate changes and/or land use, extreme events, pollutants) on the activity, the abundances and the diversity of model microbial functional groups involved in the ecosystem functioning.

The LEM staff involved in REGARDS are:

Franck Poly (CR CNRS) franck.poly(at)univ-lyon1.fr
Thomas Pommier (CR INRA) thomas.pommier(at)univ-lyon1.fr
Nadine Guillaumaud (Tech Univ Lyon) guillau(at)univ-lyon1.fr
Catherine Lerondelle (IE INRA) lerondel(at)univ-lyon1.fr