Regulation of PhoR/B system on utilization of phosphorus and Plt biosynthesis in Pseudomonas sp. H78

Abstract:

[Objective] Pseudomonas protegens H78 can secrete three antibiotics including pyoluteorin (Plt), pyrrolnitrin and 2,4-diacetylphloroglucinol. This study focused on regulation of the two component system PhoR/B on phosphorus absorption and utilization and Plt biosynthesis. [Methods] phoR and phoB genes were deleted using non-scar homologous recombination method. The lacZ reporter gene was used to assess the regulation of PhoR/B system on Pst phosphorus transport system. The cell growth of wild-type and mutant was determined, cultured in minimal medium containing different concentrations of phosphate. The production of Plt was determined in KB medium. [Results] The β-galactosidase activity of pstS′-′lacZ fusion in H78 was 15 times that in mutant. The growth of H78 was three times that in mutant when phosphate starvation. The production of Plt in H78 was two times that in mutant in KMB medium. [Conclusion] PhoR/B system positively regulates the expression of the Pst phosphorus transport system. PhoR/B facilitates phosphorus absorption and utilization during phosphate starvation and positively regulates the Plt biosynthesis as well.

Key words:Pseudomonas sp. H78, PhoR/B, Pst system, Phosphate starvation, Pyoluteorin