Rhizosphere competence and the role of root colonization in biocontrol

In order to efficiently protect the root system against the attack of phytopathogenic microorganism a biocontrol strain has to establish itself in the rhizosphere. After inoculation the biocontrol agent has to colonize the rhizosphere, in which processes such as growth, chemotaxis, motility, etc play essential roles. This chapter will focus on the mechanisms of Pseudomonas biocontrol strains, which are involved in rhizosphere competence and the role of root colonization in biological control. It will address experimental approaches to elucidate colonization genes and give a brief overview of genes and traits that are involved in root colonization.