Bacillus safensis LS01 provides biological control of potato common scab with potential effects from secondary metabolites.

Aims: Potato common scab (CS), caused by pathogenic Streptomyces, is a devastating disease affecting potato crops worldwide. Antagonistic microorganisms have been used as biological control agents to inhibit Streptomyces scabies and reduce the use of synthetic pesticides. However, identifying beneficial microorganisms for controlling CS remains undetermined.

Methods and results: Strain LS01 was isolated from the geocaulosphere soils of healthy potato tubers. In vitro and pot experiments demonstrated that strain LS01 significantly inhibited the mycelial growth and sporulation of S. scabies, thereby reducing the severity of CS. Sequencing of the 16S rRNA of LS01 indicated that the strain belonged to the species Bacillus safensis. Whole-genome sequencing, metabolomic analysis with liquid chromatograph mass spectrometer, and uultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry analyses indicated that hygromycin B and plantazolicin may be the active secondary metabolites by which B. safensis LS01 inhibits S. scabies.

Conclusions: Bacillus safensis LS01 is a potential biocontrol agent for CS, with its secondary metabolites exerting effective inhibitory effects.