Gluconic acid-producing Pseudomonas sp. prevent γ-actinorhodin biosynthesis by Streptomyces coelicolor A3(2)
- 488 Downloads
Streptomyces are ubiquitous soil bacteria well known for their ability to produce a wide range of secondary metabolites including antibiotics. In their natural environments, they co-exist and interact with complex microbial communities and their natural products are assumed to play a major role in mediating these interactions. Reciprocally, their secondary metabolism can be influenced by the surrounding microbial communities. Little is known about these complex interactions and the underlying molecular mechanisms. During pairwise co-culture experiments, a fluorescent Pseudomonas, Pseudomonas fluorescens BBc6R8, was shown to prevent the production of the diffusible blue pigment antibiotic γ-actinorhodin by Streptomyces coelicolor A3(2) M145 without altering the biosynthesis of the intracellular actinorhodin. A mutant of the BBc6R8 strain defective in the production of gluconic acid from glucose and consequently unable to acidify the culture medium did not show any effect on the γ-actinorhodin biosynthesis in contrast to the wild-type strain and the mutant complemented with the wild-type allele. In addition, when glucose was substituted by mannitol in the culture medium, P. fluorescens BBc6R8 was unable to acidify the medium and to prevent the biosynthesis of the antibiotic. All together, the results show that P. fluorescens BBc6R8 impairs the biosynthesis of the lactone form of actinorhodin in S. coelicolor by acidifying the medium through the production of gluconic acid. Other fluorescent Pseudomonas and the opportunistic pathogen Pseudomonas aeruginosa PAO1 also prevented the γ-actinorhodin production in a similar way. We propose some hypotheses on the ecological significance of such interaction.
KeywordsStreptomyces coelicolor Pseudomonas Interaction Gluconic acid γ-Actinorhodin biosynthesis
This work was founded by the French National Research Agency through the Laboratory of Excellence ARBRE (ANR-11-LABX-0002-01), by the French National Institute for Agricultural Research (INRA) and Région Lorraine. JG was supported by a CJS (Contrat Jeune Scientifique) Grant from INRA. We thank Jean-Selim Medot for his help in this work.
- Barker WW, Welch SA, Banfield JF (1997) Biogeochemical weathering of silicate minerals. Rev Mineral Geochem 35:391–428Google Scholar
- Deveau A, Brulé C, Palin B et al (2010) Role of fungal trehalose and bacterial thiamine in the improved survival and growth of the ectomycorrhizal fungus Laccaria bicolor S238 N and the helper bacterium Pseudomonas fluorescens BBc6R8: role of trehalose and thiamine in mutualistic interaction. Environ Microbiol Rep 2:560–568PubMedCrossRefGoogle Scholar
- Kamilova F, Kravchenko LV, Shaposhnikov AI et al (2006) Organic acids, sugars, and L-tryptophane in exudates of vegetables growing on stonewool and their effects on activities of rhizosphere bacteria. Mol Plant Microbe Interact MPMI 19:250–256Google Scholar
- Kieser T, Bibb MJ, Buttner MJ et al (2000) Practical streptomyces genetics. John Innes Fundation, Norwich, UKGoogle Scholar
- Sverdrup H, Warfvinge P (1995) Estimating field weathering rates using laboratory kinetics. Rev Mineral Geochem 31:485–541Google Scholar