NWO - Bacterial interactions in soil: the role of volatiles as infochemicals and competitive tools

Soil is a complex heterogenous and dynamic environment harbouring a huge diversity of bacteria which are often in competitive intra- and inter-specific interactions with each other. The importance of bacterial interactions in microbial ecology is increasingly recognized. However, little attention is paid to the role of bacterial volatiles in microbial interactions.
It is well known that soil microorganisms can produce a wide variety of chemical compounds, including volatiles. Volatiles can distribute well in the soil matrix as they are able to diffuse through both the water- and gas-filled pores in soil. Hence, volatiles are excellent candidates for the discovery of new modes of microbial communication, and could be important in interactions between relatively distantly distributed soil microorganisms. So far, little is known about the actual role of volatiles in soil microbial interactions.
In this project I test the hypothesis that bacterial volatiles are playing significant roles in bacterial inter-specific competitive interactions in soil. Volatiles could act as infochemicals providing information on the competing strains and as antimicrobial compounds directly suppressing competitors. Using soil model-systems and selected soil bacterial strains I will study the impact of bacterial volatiles on phenotypic changes, competitive ability and gene expression. The experiments have an increasing level of complexity i.e. from single model populations, via mixtures to whole soil microbial communities. A suite of state-of-the-art molecular and chemical methods and novel cultivation techniques will be used to study both the production and impact of volatiles.
The research will contribute to the understanding of ?communication? within soil microbial communities and, consequently, of the functioning of soil microbial communities. With respect to the latter, particular attention will be paid to the role of volatiles in natural suppression of plant-pathogenic fungi. An additional possible outcome of the research is the discovery of novel compounds, potentially with therapeutic value, produced as result of volatile mediated interactions.