The degradation fragments of gamma-glutamyl transpeptidase fromBacillus subtilisBU108 have antimicrobial activity againstStreptomyces scabiei

Bacillusspecies are often regarded as ideal biocontrol agents against plant pathogens, which can produce various antimicrobial peptides (AMPs). In this study, strain BU108 with good antimicrobial activity againstStreptomyces scabieiwas isolated from the rhizosphere soil of a potato field, which was then identified asBacillus subtilisthrough 16S rDNA sequence analysis. An antimicrobial protein was purified by ammonium sulfate precipitation, ion exchange chromatography and ultrafiltration. The active sample showed a single band on SDS-PAGE gel, which was identified by mass spectrometry as partial fragments of gamma-glutamyl transpeptidase (GGT). To verify this new finding, three potential AMPs (KT20, IF20 and AE26) were predicted based on the sequence and structure of GGT, and the antimicrobial activity test confirmed two AMPs (KT20 and IF20). As GGT was involved in the metabolism of glutathione in former references, in this study, we reported the antimicrobial activity of its degradation fragments for the first time, which not only enriched the antimicrobial substance ofBacillus subtilis, but also provided a new choice for potato common scab biocontrol.

Automated summary

In this study, a Bacillus subtilis strain with good antimicrobial activity against Streptomyces scabiei was isolated from the rhizosphere soil of a potato field, and an antimicrobial protein was purified from it. The protein was identified as partial fragments of gamma-glutamyl transpeptidase (GGT), and two antimicrobial peptides were confirmed based on its sequence and structure. This research not only enriched the antimicrobial substances of Bacillus subtilis, but also provided a new option for potato common scab biocontrol.