Mediators of mutualistic microbe-microbe interactions.

The co-existence of different microbial species in one habitat is prerequisite for many ecosystem processes. To facilitate co-habitation of ecological niches, intricate mechanisms have evolved that regulate the growth and the behaviour of microbes. A crucial aspect for the establishment and maintenance of a microbial population is the communication among species. Whereas intraspecies communication processes have been widely studied, little is known about the molecular mechanisms underlying interspecies interactions. Through the advance of modern analytical and sequencing technologies, we are now beginning to gain deeper insights into these complex processes. A key feature of microbe-microbe interaction is the secretion of chemical mediators to influence either the microbial partner or co-occurring higher organisms to shape the specific microenvironment. Here we summarize recent advances in understanding the role of natural products as regulators of microbial interaction in various ecological niches. Special attention is paid to mutualistic relationships with relevance for ecology and agriculture as well as medicine.