Bacillus polymyxa, Pseudomonas cepacia and Pseudomonas fluorescens are present in the rhizosphere of many crop plants. Little is known about microbial interactions in the rhizosphere. We investigated the type of interaction between these species under iron limitation. We found that, in mixed batch cultures, P. cepacia stimulates the growth of B. polymyxa and this stimulation can be observed also in low iron medium. Cell-free supernatants of cultures of P. fluorescens with various amounts of the siderophore pyoverdine also stimulate the growth of B. polymyxa. In this case we observed a positive correlation between pyoverdine concentration and growth stimulation. Purified pyoverdine also affects positively the growth of B. polymyxa. © 1993 Springer Verlag.
All Science Journal Classification (ASJC) codes
- Molecular Biology