Two-Component Response Regulator DegU Controls the Expression of Bacilysin in Plant-Growth-Promoting Bacterium Bacillus amyloliquefaciens FZB42

Abstract

The plant-growth-promoting-rhizobacteria Bacillus amyloliquefaciens FZB42 possess an enormous potential to synthesize a wide range of antimicrobial, antiviral and nematocidal compounds. One of them, the dipeptide antibiotic bacilysin, is synthesized by FZB42 during exponential growth. Here, we have demonstrated that bacilysin is positively regulated by the two-component response regulator DegU at the transcriptional level. In addition, ScoC (Hpr), a transition state regulator, negatively controlled expression of the bacA gene, which is the first gene within the bacilysin operon. Both DegU and ScoC were bound directly at the bacA promoter region. Furthermore, a monocistronic gene located in close vicinity of the bac operon and essential for bacilysin production, ywfH, was also regulated by DegU. Transcription of the bac operon and of the ywfH gene in B. amyloliquefaciens FZB42 was positively controlled by the DegU global regulator protein. The role of interactions within a ternary complex formed by the antagonistically acting regulators DegU and ScoC as well as the bacA promoter sequence remains to be elucidated.

Biochemistry, genetics and regulation of bacilysin biosynthesis and its significance more than an antibiotic

“…ScoC box2 and CodY box overlap in bacABCDEF operon upstream [86]. As recently, reported, the putative binding sites of both DegU and ScoC are found in the bacA promoter region in B. amyloliquefaciens [85].…”

“…CcpA (catabolite control protein A) also positively regulates degU through binding directly to the degU upstream region [84]. DegU was shown to positively regulate bac operon as well as the monocistronic ywfH (bacG) at the transcriptional level in Bacillus amyloliquefaciens [85]. Another protein, the transition state regulator ScoC (Hpr), is known to negatively regulate protease production and sporulation.…”

Amylocyclicin, a Novel Circular Bacteriocin Produced by Bacillus amyloliquefaciens FZB42

“…Sequencing of the region next to the transposon insertion revealed that in mutant WY01, the RBAM_029230 gene was interrupted by the transposon insertion, while mutant RSpMarA2 harbored an interrupted degU gene, suggesting that synthesis of the antibacterial compound is strictly dependent on DegU. DegU, a global transcription regulator, activates the nonribosomal synthesis of the polyketide difficidin, the antifungal lipopeptide bacillomycin D, and bacilysin in FZB42 (23,24).…”

Complete Genome Sequence of Bacillus subtilis BAB-1, a Biocontrol Agent for Suppression of Tomato Gray Mold

“…As in other prokaryotes, two-component signal transduction systems of B. subtilis are important elements of the adaptive response to a variety of external conditions (9). A total of 35 two-component systems (TCS) were identified from the genome of strain BAB-1, including the biocontrol function-related TCS comP / comA (10), phoR / phoP (11), and degU / degS (12). Finally, we identified 86 transposons, 25 phage-like elements, and type III restriction modification systems in strain BAB-1 genome.…”