Role of CbrB in the biocontrol strain Pseudomonas protegens Pf-5

Abstract:

[Objective] To explore the effects of CbrB from the carbon catabolite repression system on the biocontrol performance of Pseudomonas protegens Pf-5. [Methods] The mutant Pf5274 with the markerless deletion of the coding region of cbrB was constructed by a double-crossover recombination event based on pJQ200SK. Moreover, the complementary strain of cbrB and the control strains were constructed by the plasmid complementation method based on pBBR1Am. Lastly, the effects of CbrB on the growth, biofilm formation, motility, antifungal activity, and pyoluteorin synthesis of Pf-5 were analyzed by the measurement of OD₆₀₀, crystal violet staining, agar plate culture, plate confrontation method, and pltL'-'lacZ fusion report strains, respectively. [Results] CbrB greatly slowed the growth of Pf-5 in the natural medium LB, but greatly sped up the growth of Pf-5 in the basic medium M9-glucose. In addition, CbrB significantly promoted the motility but inhibited the biofilm formation, antifungal activity, and pyoluteorin synthesis of Pf-5. [Conclusion] CbrB plays a role in regulating the growth, biofilm formation, motility, antifungal activity, and pyoluteorin synthesis of P. protegens Pf-5, thus regulating the biocontrol performance of this strain. This study provides a theoretical basis for the biocontrol capabilities of strains by genetic engineering and lays a foundation for probing into the biosynthesis of pyoluteorin.