séminaire d'agroécologie

"Fungal-bacterial interactions as drivers of microbial community : structure and functioning in terrestrial ecosystems" - Prof. Hans Van Veen, directeur du Centre Hollandais d'Ecologie Terrestre, mardi 13 Octobre à 9h30, salle de conférence, INRA


Bacteria and fungi are the dominant components of the living soil. Together they are responsible for the majority of key ecosystem functions, including nutrient and energy cycling, sustaining plant growth, cleaning of percolating water, soil structuring, etc. In the water-unsaturated zone, bacteria and fungi may occupy similar niches and use similar substrates, which results in a large variety of interactions between the two groups of micro-organisms, including antagonism, competition and mutualism. Some of these interactions have been investigated extensively, for instance antagonism in the framework of biological control of pathogens. These studies were performed mainly at the level of specific populations. However, we have little information on the consequences of these interactions for the structure and functioning of the communities of both groups. Information will be presented from few case studies on how specific bacteria influence the structure and functioning of the fungal community and vice versa how the development of fungi is affecting the associated bacterial community. These cases are examples of the research within the NIOO-KNAW on this subject. Results are shown on i) the impact of a mycophagous (fungal-eating) bacterium on the fungal community structure in soil, ii) the selection of bacteria by white rot-fungi upon their invasion of wood, iii) the suppression of plant pathogenic fungi as a result of interspecies interactions of non-antagonistic bacteria and iv) the effects of saprotrophic fungi on the composition of rhizosphere bacteria. In all cases, considerable changes in the community structure and functioning were observed, even when measurable quantitative effects were absent due to the low abundance of the interactive populations. It shows the importance of these interactions for the composition and functioning of the fungal or bacterial communities in terrestrial ecosystems.

Prof. Hans Van Veen
Director of the NIOO-KNAW-Centre for Terrestrial Ecology
head of the Department of Plant-Micro-organism Interactions
The Netherlands
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