Secondary metabolites help biocontrol strain Pseudomonas fluorescens CHA0 to escape protozoan grazing.

ABSTRACT: In soil ecosystems, bacteria must cope with predation activity, which is attributed mainly to protists. The development of antipredation strategies may help bacteria maintain higher populations and persist longer in the soil. We analyzed the interaction between the root-colonizing and biocontrol strain Pseudomonas fluorescens CHA0 and three different protist isolates (an amoeba, a flagellate, and a ciliate). CHA0 produces a set of antibiotics, HCN, and an exoprotease. We observed that protists cannot grow on CHA0 but can multiply on isogenic regulatory mutants that do not produce the extracellular metabolites. The in vitro responses to CHA0 cells and its exoproducts included growth inhibition, encystation, paralysis, and cell lysis. By analyzing the responses of protists to bacterial super

SUBMITTER: Jousset A 

PROVIDER: S-EPMC1636139 | biostudies-literature | 2006 Nov

REPOSITORIES: biostudies-literature