Isolation and characterization of Bacillus velezensis strain B19 for biocontrol of Panax notoginseng root rot

•Bacillus velezensi strain B19 from Sanqi rhizosphere inhibits pathogenic Fusarium.•B19 metabolizes autotoxic saponins and reduces Sanqi root rot incidence.•B19′s genome encodes 13 biosynthetic gene clusters.•B19 produces volatile organic compounds to inhibit pathogenic fungi.•Saponins enhance B19′s motility/chemotaxis and biofilm-forming ability.