Evaluation of the biocontrol potential of Bacillus sp. WB against Fusarium oxysporum f. sp. niveum

•Bacillus sp. WB, was isolated from healthy watermelon rhizosphere.•The strain WB exhibited biocontrol activity against Fusarium oxysporum f. sp. niveum.•Bacillus sp. WB changed structure of microbial community in the rhizosphere of watermelon.•Application of Bacillus sp. WB decreased the incidence of Fusarium wilt in watermelon.